S-1/A

Use these links to rapidly review the document
TABLE OF CONTENTS
INDEX TO FINANCIAL STATEMENTS

As filed with the Securities and Exchange Commission on July 12, 2013

Registration No. 333-189109

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Amendment No. 2
to

FORM S-1
REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

Athlon Energy Inc.
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of
incorporation or organization) 1311
(Primary Standard Industrial
Classification Code Number) 46-2549833
(I.R.S. Employer
Identification Number)

420 Throckmorton Street, Suite 1200
Fort Worth, Texas 76102
(817) 984-8200
(Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)

Robert C. Reeves
President and Chief Executive Officer
420 Throckmorton Street, Suite 1200
Fort Worth, Texas 76102
(817) 984-8200
(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:
Sean T. Wheeler Divakar Gupta Latham & Watkins LLP 811 Main Street, Suite 3700 Houston, Texas 77002 (713) 546-5400	Gerald M. Spedale Jason A. Rocha Baker Botts L.L.P. 910 Louisiana Street Houston, Texas 77002 (713) 229-1234

         Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this Registration Statement.

         If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box: o

         If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

         If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

         If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

         Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer o Accelerated filer o Non-accelerated filer ý
(Do not check if a
smaller reporting company) Smaller reporting company o

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until this Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We and the selling stockholders may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state or other jurisdiction where the offer or sale is not permitted.

Subject to Completion, dated July 12, 2013

PROSPECTUS

               Shares

Athlon Energy Inc.

Common Stock
$      per share

        This is the initial public offering of our common stock. We are selling                 shares of our common stock. We expect the initial public offering price to be between $            and $            per share.

        The selling stockholders named in this prospectus have granted the underwriters an option to purchase up to                additional shares of common stock to cover over-allotments. We will not receive any of the proceeds from the sale of the shares by the selling stockholders.

        We have been approved to list our common stock on the New York Stock Exchange under the symbol "ATHL."

Investing in our common stock involves risks. See "Risk Factors" beginning on page 18.

        We are an emerging growth company as that term is used in the Jumpstart Our Business Startups Act of 2012, and as such, we have elected to take advantage of certain reduced public company reporting requirements for this prospectus and future filings. See "Risk Factors" and "Prospectus Summary—Emerging Growth Company Status."

        Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

	Per Share	Total
Initial Public Offering Price	$	$
Underwriting Discounts and Commissions	$	$
Proceeds to Athlon Energy Inc. (before expenses)	$	$

        The underwriters expect to deliver the shares to purchasers on or about                        , 2013 through the book-entry facilities of The Depository Trust Company.

Citigroup

                        , 2013

TABLE OF CONTENTS

Prospectus Summary	1
The Offering	10
Summary Consolidated Financial, Reserve and Operating Data	12
Risk Factors	18
Cautionary Note Regarding Forward-Looking Statements	49
Use of Proceeds	51
Dividend Policy	51
Capitalization	52
Dilution	53
Selected Historical Consolidated Financial Data	54
Management's Discussion and Analysis of Financial Condition and Results of Operations	55
Business	82
Management	105
Certain Relationships and Related Party Transactions	123
Corporate Reorganization	129
Principal and Selling Stockholders	131
Description of Capital Stock	133
Shares Eligible for Future Sale	140
Material U.S. Federal Income Tax Consequences to Non-U.S. Holders	142
Underwriting (Conflicts of Interest)	146
Legal Matters	153
Experts	153
Where You Can Find More Information	153
Glossary	G-1
Index to Financial Statements	F-1

You should rely only on the information contained in this prospectus and any free writing prospectus prepared by or on behalf of us or to which we have referred you. Neither we nor the underwriters have authorized anyone to provide you with information different from that contained in this prospectus and any free writing prospectus. We are offering to sell shares of common stock and seeking offers to buy shares of common stock only in jurisdictions where offers and sales are permitted. The information in this prospectus is accurate only as of the date of this prospectus, regardless of the time of delivery of this prospectus or any sale of the common stock.

Industry and Market Data

        The market data and certain other statistical information used throughout this prospectus are based on independent industry publications, government publications or other published independent sources. Some data is also based on our good faith estimates. Although we believe these third-party sources are reliable, neither we nor the underwriters have independently verified the information and cannot guarantee its accuracy and completeness. The industry in which we operate is subject to a high degree of uncertainty and risk due to a variety of factors, including those described in the section entitled "Risk Factors." These and other factors could cause results to differ materially from those expressed in these publications.

i

PROSPECTUS SUMMARY

This summary provides a brief overview of information contained elsewhere in this prospectus. Because it is abbreviated, this summary does not contain all of the information that you should consider before investing in our common stock. You should read the entire prospectus carefully before making an investment decision, including the information presented under the headings "Risk Factors," "Cautionary Note Regarding Forward-Looking Statements" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the historical consolidated financial statements and the related notes thereto appearing elsewhere in this prospectus. We have provided definitions for certain terms used in this prospectus in the "Glossary" appearing elsewhere in this prospectus. References to our estimated proved reserves and PV-10 are derived from our proved reserve reports prepared by Cawley, Gillespie & Associates, Inc.

In this prospectus, unless the context otherwise requires, the terms "we," "us," "our" and "Athlon" refer to Athlon Holdings LP and its subsidiaries before the completion of our corporate reorganization in April 2013 and Athlon Energy Inc. and its subsidiaries as of the completion of our corporate reorganization and thereafter. Please read "Corporate Reorganization." Unless otherwise indicated, the information contained in this prospectus assumes that the underwriters do not exercise their option to purchase additional shares from Apollo and that the New Holdings Units subject to the terms of the exchange agreement are not exchanged for shares of our common stock. The information throughout this prospectus assumes and gives effect to a                for 1 stock split that will be effected as of the effective date of the registration statement of which this prospectus forms a part.

Overview

        We are an independent exploration and production company focused on the acquisition, development and exploitation of unconventional oil and liquids-rich natural gas reserves in the Permian Basin. The Permian Basin spans portions of Texas and New Mexico and is composed of three primary sub-basins: the Delaware Basin, the Central Basin Platform and the Midland Basin. All of our properties are located in the Midland Basin. Our drilling activity is currently focused on the low-risk vertical development of stacked pay zones, including the Spraberry, Wolfcamp, Cline, Strawn, Atoka and Mississippian formations, which we refer to collectively as the Wolfberry play. We are a returns-focused organization and have targeted the Wolfberry play in the Midland Basin because of its favorable operating environment, consistent reservoir quality across multiple target horizons, long-lived reserve characteristics and high drilling success rates.

        We were founded in August 2010 by a group of former executives from Encore Acquisition Company following its acquisition by Denbury Resources, Inc. With an average of approximately 20 years of industry experience and over 10 years of history working together, our founding management has a proven track record of working as a team to acquire, develop and exploit oil and natural gas reserves in the Permian Basin as well as other resource plays in North America.

        Our acreage position was 124,925 gross (98,348 net) acres at May 31, 2013, which we group into three primary areas based on geographic location within the Midland Basin: Howard, Midland & Other and Glasscock. From the time we began operations in January 2011 through May 31, 2013, we have operated up to eight vertical drilling rigs simultaneously and have drilled 230 gross operated vertical Wolfberry wells with a 99% success rate across all three areas. This activity has allowed us to identify and de-risk our multi-year inventory of 4,902 gross (3,857 net) vertical drilling locations, while also identifying 1,079 gross (931 net) horizontal drilling locations in specific areas based on geophysical and technical data. As we continue to expand our vertical drilling activity to our undeveloped acreage, we expect to identify additional horizontal drilling locations.

1

        The following table summarizes our leasehold position and identified net drilling locations by primary geographic area as of May 31, 2013:

					Identified Drilling Locations1
					Vertical
	Acreage
					Net 40-acre2		Net 20-acre		Net Total		Drilling Inventory3 (years)		Net Horizontal4
	Gross		Net
Howard		69,661		51,556		1,140		1,291		2,431		37		403
Midland & Other		36,694		33,709		390		414		804		20		316
Glasscock		18,570		13,083		267		355		622		24		212
Total		124,925		98,348		1,797		2,060		3,857		30		931

¹

Represents locations specifically identified by management based on evaluation of applicable geologic, engineering and production data. The drilling locations on which we actually drill wells will ultimately depend on the availability of capital, regulatory approvals, oil and natural gas prices, costs, actual drilling results and other factors.

²

Includes 597 gross (560 net) locations booked as proved undeveloped locations in our proved reserve report as of December 31, 2012.

³

Based on our 2013 drilling program on a gross basis.

⁴

Includes horizontal drilling locations targeting Wolfcamp A, Wolfcamp B, Wolfcamp C, Cline and Mississippian intervals, which comprise 311 gross (272 net), 357 gross (317 net), 133 gross (125 net), 227 gross (193 net) and 51 gross (24 net) locations, respectively.

        Since our inception, we have completed two significant acquisitions and seven bolt-on acquisitions. At the time of each acquisition, based on internal engineering estimates, these properties collectively contributed approximately 3,600 BOE/D of production and approximately 43 MMBOE of proved reserves. We have significantly grown production and proved reserves on the properties we acquired through the successful execution of our low-risk vertical drilling program. From the time we began operations in January 2011 through May 31, 2013, we have drilled 230 gross operated vertical Wolfberry wells on our properties with a 99% success rate and grown our production to 10,971 BOE/D for April 2013.

        In 2012, our development capital was approximately $276 million and we drilled a total of 133 gross (124 net) vertical Wolfberry wells. In 2013, we plan to invest $317 million of development capital, including $15 million for infrastructure, leasing and capitalized workovers, and drill 162 gross (150 net) vertical Wolfberry wells. We also plan to invest $33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells. We currently operate seven vertical drilling rigs on our properties and have operated between five and eight vertical drilling rigs since October 2011. We expect to take delivery of our first horizontal rig in the third quarter of 2013.

        Our estimate of proved reserves is prepared by Cawley, Gillespie & Associates, Inc. ("CG&A"), our independent petroleum engineers. As of December 31, 2012, we had 86 MMBOE of proved reserves, which were 58% oil, 22% NGLs and 20% natural gas and 30% proved developed. As of December 31, 2012, the PV-10 of our proved reserves was approximately $867 million, 59% of which was attributed to proved developed reserves. Our proved undeveloped reserves, or PUDs, are composed of 597 gross (560 net) potential vertical drilling locations. The following table provides

2

information regarding our proved reserves and production by area as of December 31, 2012, except as otherwise noted below:

	Estimated Total Proved Reserves
														Average Net Daily Production3 (BOE/D)
	Oil (MMBbls)		NGLs (MMBbls)		Natural Gas (Bcf)		Total (MMBOE)		% Liquids1			PV-102 (in millions)				R/P Ratio (years)
Howard		20.2		7.3		36.3		33.5		82	%	$	365.4		4,160		22.1
Midland & Other		17.6		8.3		44.7		33.3		78	%		337.0		4,825		18.9
Glasscock		11.6		3.7		22.7		19.2		80	%		164.2		1,986		26.4
Total		49.4		19.3		103.7		86.0		80	%	$	866.6		10,971		21.5

¹

Includes both oil and NGLs.

²

PV-10 is a non-GAAP financial measure. Standardized Measure is the closest GAAP measure and our Standardized Measure was $850.9 million at December 31, 2012. For additional information about PV-10 and how it differs from the Standardized Measure, please read "Summary Consolidated Financial, Reserve and Operating Data—Non-GAAP Financial Measures."

³

During April 2013, inclusive of oil production of 6,345 Bbls/D in total.

Our Business Strategy

        We maintain a disciplined and analytical approach to investing in which we seek to direct capital in a manner that will maximize our rates of return as we develop our extensive resource base. Key elements of our strategy are:

•

Grow reserves, production and cash flow with our multi-year inventory of low-risk vertical drilling locations.  We have considerable experience managing large scale drilling programs and intend to efficiently develop our acreage position to maximize the value of our resource base. During 2012, we invested $276 million of development capital, drilled 133 gross (124 net) vertical Wolfberry wells and grew production by 4,204 BOE/D, or 93%, from 4,506 BOE/D in the fourth quarter of 2011 to 8,710 BOE/D in the fourth quarter of 2012. We also increased proved reserves by 40 MMBOE, or 86%, from 46 MMBOE at December 31, 2011 to 86 MMBOE at December 31, 2012. In 2013, we plan to invest approximately $317 million of development capital, including $15 million for infrastructure, leasing and capitalized workovers, and drill 162 gross (150 net) vertical Wolfberry wells. We also plan to invest $33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells in order to continue to grow our production and reserves.

•

Continuously improve capital and operating efficiency.  We continuously focus on optimizing the development of our resource base by seeking ways to maximize our recovery per well relative to the cost incurred and to minimize our operating cost per BOE produced. We apply an analytical approach to track and monitor the effectiveness of our drilling and completion techniques and service providers. Additionally, we seek to build infrastructure that allows us to achieve economies of scale and reduce operating costs. Specifically, we have:

•

achieved first six-month average daily production volumes on our operated wells in Howard County that outperformed average industry vertical well results by 102% since 2010, based on data from the Texas Railroad Commission;

•

achieved first six-month average daily production volumes on our operated wells in Midland County that outperformed average industry vertical well results by 68% since 2010, based on data from the Texas Railroad Commission;

3

•

reduced average development costs per gross well in our Midland & Other area from $2.4 million in the first quarter of 2012 to $2.1 million in the fourth quarter of 2012, an improvement of 9%;

•

reduced average development costs per gross well in our Howard and Glasscock areas from $2.0 million in the first quarter of 2012 to $1.8 million in the fourth quarter of 2012, an improvement of 12%;

•

reduced the time from spud to rig release in our Howard and Glasscock areas from 16 days in the fourth quarter of 2011 to 8 days in the first quarter of 2013, an improvement of 50%; and

•

reduced LOE from $13.82 per BOE for 2011 to $9.89 per BOE for 2012, an improvement of 28%.

•

Balance capital allocation between our lower risk vertical drilling program and horizontal development opportunities.  We have historically focused on optimizing our vertical drilling and completion techniques across our acreage position. Vertical drilling involves less operational, financial and other risk than horizontal drilling, and we view our vertical development drilling program as "low risk" because the drilling locations were selected based on our extensive delineation drilling and production history in the area and well-established industry activity surrounding our acreage. Many operators in the Midland Basin are actively drilling horizontal wells, which is more expensive than drilling vertical Wolfberry wells but potentially recovers disproportionately more hydrocarbons per well. We monitor industry horizontal drilling activity and intend to utilize the knowledge gained from the increase in industry horizontal drilling in the Midland Basin. In the second half of 2013, we intend to supplement our vertical drilling with horizontal drilling in circumstances where we believe that horizontal drilling should offer competitive rates of return.

•

Evaluate and pursue oil-weighted acquisitions where we can add value through our technical expertise and knowledge of the basin.  We have significant experience acquiring and developing oil-weighted properties in the Permian Basin, and we expect to continue to selectively acquire additional properties in the Permian Basin that meet our rate-of-return objectives. Since our formation, we have completed two significant acquisitions and seven bolt-on acquisitions that have given us a unique and highly attractive acreage position, underpinned by strong baseline production and proved reserves. We believe our experience as a leading operator and our infrastructure footprint in the Permian Basin provide us with a competitive advantage in successfully executing and integrating acquisitions.

•

Maintain a disciplined, growth-oriented financial strategy.  We intend to fund our growth predominantly with internally generated cash flows while maintaining ample liquidity and access to capital markets. Substantially all of our lease terms allow us to allocate capital among projects in a manner that optimizes both costs and returns, resulting in a highly efficient drilling program. In addition, these terms allow us to adjust our capital spending depending on commodity prices and market conditions. We expect our operating cash flows, availability under our credit agreement and the net proceeds of this offering to be sufficient to fund our capital expenditures and other obligations necessary to execute our business plan in 2013. Furthermore, we plan to hedge a significant portion of our expected production in order to stabilize our cash flows and maintain liquidity, allowing us to sustain a consistent drilling program, thereby preserving operational efficiencies that help us achieve our targeted rates of return.

4

Our Competitive Strengths

        We have a number of competitive strengths that we believe will help us to successfully execute our business strategies, including:

•

High caliber management team with substantial technical and operational expertise.  Our founding management team has an average of approximately 20 years of industry experience and over 10 years of history working together with a proven track record of value creation at publicly traded oil and natural gas companies, including Encore Acquisition Company, XTO Energy Inc., Apache Corporation and Anadarko Petroleum Corporation. As of May 31, 2013, we had 23 engineering, land and geosciences technical personnel in our Fort Worth and Midland offices, with personnel experienced in both conventional and unconventional drilling operations. We believe our management and technical team is one of our principal competitive strengths due to our team's industry experience and history of working together in the identification, execution and integration of acquisitions, cost efficient management of profitable, large scale drilling programs and disciplined allocation of capital focused on rates of return.

•

High quality asset base with significant oil exposure in the Midland Basin.  Our acreage is concentrated in Howard, Midland and Glasscock counties, which are some of the most active counties in the Midland Basin. Since 2010, more vertical wells have been drilled in each of Howard and Glasscock counties than any other county in the Midland Basin, and Midland County has been the fifth most active county, based on data from the Texas Railroad Commission. Of the 9,242 vertical wells drilled in the Midland Basin since 2010, 1,579 (17%) have been drilled in Howard County, 1,255 (14%) have been drilled in Glasscock County and 714 (8%) have been drilled in Midland county. Furthermore, we have intentionally focused on crude oil and liquids opportunities to benefit from the relative disparity between oil and natural gas prices on an energy-equivalent basis, which has persisted over the last several years and which we expect to continue in the future. Approximately 58% and 22% of our proved reserves were oil and NGLs, respectively, as of December 31, 2012.

•

De-risked Midland Basin acreage position with multi-year vertical drilling inventory.  Since our management team commenced our development program in January 2011 through May 31, 2013, we have drilled 230 gross operated vertical Wolfberry wells across our leasehold position with a 99% success rate. Based on our extensive analysis of geophysical and technical data gained as a result of our vertical drilling program and from offset operator activity, as of May 31, 2013, we have identified 2,298 gross (1,797 net) vertical drilling locations on 40-acre spacing and an additional 2,604 gross (2,060 net) vertical drilling locations on 20-acre spacing across our leasehold, all of which target crude oil and NGLs as the primary objectives across stacked pay zones. Together, these 4,902 gross (3,857 net) identified drilling locations represent over 30 years of drilling inventory based on our expected 2013 drilling program. We view this drilling inventory as de-risked because the drilling locations were selected based on our extensive delineation drilling and production history in the area and well-established industry activity surrounding our acreage.

•

Extensive horizontal development potential.  Operators have drilled hundreds of horizontal wells in the Wolfcamp, Cline and Mississippian formations in the Midland Basin, including numerous horizontal wells offsetting our acreage, and are continuing to accelerate horizontal drilling activity. Multiple Wolfcamp formations are prevalent across our entire leasehold position, and the Cline and Mississippian formations are present across portions of our leasehold position. Based on vertical well control information from our operations and the operations of offset operators, we have initially identified 311 gross (272 net) horizontal drilling locations in the Wolfcamp A formation, 357 gross (317 net) horizontal drilling locations in the Wolfcamp B formation, 133 gross (125 net) horizontal drilling locations in the Wolfcamp C formation,

5

227 gross (193 net) horizontal drilling locations in the Cline formation and 51 gross (24 net) horizontal drilling locations in the Mississippian formation. In addition, the subsurface data we have collected from our vertical drilling program also supports the potential for additional horizontal drilling in other formations, including the Strawn and Atoka formations. As we continue to expand our vertical drilling activity to our undeveloped acreage, we expect to identify additional horizontal drilling locations. Our vertical drilling has been designed to preserve these future horizontal drilling opportunities and optimize hydrocarbon recovery rates on our acreage. Beginning in the second half of 2013, we intend to supplement our vertical drilling with horizontal drilling in circumstances where we believe that horizontal drilling should offer competitive rates of return.

•

Large, concentrated acreage position with significant operational control.  Substantially all of our acreage is located in three counties in the Midland Basin. Our properties are characterized by large, contiguous acreage blocks, which has enabled us to implement more efficient and cost-effective operating practices and to capture economies of scale, including our installation of centralized production and fluid handling facilities, lowering of rig mobilization times and procurement of better vendor services. We seek to operate our properties so that we can continue to implement these efficient operating practices and control all aspects of our development program, including the selection of specific drilling locations, the timing of the development and the drilling and completion techniques used to efficiently develop our significant resource base. As of December 31, 2012, we operated approximately 99% of our proved reserves.

Our Capital Restructuring Program

        In the first quarter of 2013, we commenced a plan to enhance our overall capital structure and liquidity, including the execution of our amended and restated credit agreement in March 2013 that extends the maturity date of our reserve based lending facility to 2018. On April 17, 2013, we issued $500 million of 7³/8% senior notes due 2021 and used most of the net proceeds from the offering to reduce the outstanding borrowings under our credit agreement and repay in full and terminate our former second lien term loan, thereby extending a large portion of our then-existing debt maturity to 2021. This offering represents a continuation of our plan, as we intend to apply the estimated proceeds of this offering to further reduce the outstanding borrowings under our credit agreement, provide additional liquidity for use in our drilling program and for general corporate purposes, including potential acquisitions.

2013 Capital Budget

        In 2013, we plan to invest $317 million of development capital, including $15 million for infrastructure, leasing and capitalized workovers, and drill 162 gross (150 net) vertical Wolfberry wells. We also plan to invest $33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells.

        In Howard, we plan to invest $155 million and drill 89 gross (82 net) wells. This includes 25 gross (23 net) PUD locations to be drilled through the Atoka/Mississippian formations at depths of approximately 9,900 feet. Our EURs per well for Howard PUD locations to be drilled through the Atoka/Mississippian formations average 141 MBOE as estimated by CG&A in our proved reserve report as of December 31, 2012. In addition, we plan to drill 64 gross (59 net) unproved locations through the Atoka/Mississippian formations.

        In Midland & Other, we plan to invest $95 million and drill 44 gross (42 net) wells. This includes 19 gross (19 net) PUD locations to be drilled through the Strawn/Atoka formations at depths of approximately 11,300 feet. Our EURs per well for Midland & Other PUD locations to be drilled

6

through the Strawn/Atoka formations average 208 MBOE as estimated by CG&A in our proved reserve report as of December 31, 2012. In addition, we plan to drill 25 gross (23 net) unproved locations through the Strawn/Atoka formations.

        In Glasscock, we plan to invest $52 million and drill 29 gross (26 net) wells. This includes 8 gross (7 net) PUD locations to be drilled through the Atoka formation at depths of approximately 10,150 feet. Our EURs per well for Glasscock PUD locations to be drilled through the Atoka formation average 118 MBOE as estimated by CG&A in our proved reserve report as of December 31, 2012. In addition, we plan to drill 21 gross (19 net) unproved locations through the Atoka formation.

Risk Factors

        Investing in our common stock involves risks that include the speculative nature of oil and natural gas exploration, competition, volatile commodity prices and other material factors. For a discussion of these risks and other considerations that could negatively affect us, including risks related to this offering and our common stock, please read "Risk Factors" and "Cautionary Note Regarding Forward-Looking Statements."

Organizational Structure

        Athlon Energy Inc. is a holding company and its sole assets are controlling equity interests in Athlon Holdings LP and its subsidiaries. Athlon Energy Inc. operates and controls all of the business and affairs and consolidates the financial results of Athlon Holdings LP and its subsidiaries. Prior to our reorganization in April 2013, Apollo Investment Fund VII, L.P. and its parallel funds (the "Apollo Funds"), members of our management team and certain employees owned all of the Class A limited partner interests in Athlon Holdings LP and members of our management team and certain employees owned all of the Class B limited partner interests in Athlon Holdings LP. In the reorganization, the Apollo Funds entered into a number of distribution and contribution transactions pursuant to which the Apollo Funds exchanged their Class A limited partner interests in Athlon Holdings LP for common stock of Athlon Energy Inc. The remaining holders of Class A limited partner interests in Athlon Holdings LP have not exchanged their interests in the reorganization transactions. In addition, the holders of the Class B limited partner interests in Athlon Holdings LP exchanged their interests for common stock of Athlon Energy Inc. Upon closing of this offering, the limited partnership agreement of Athlon Holdings LP will be amended and restated to, among other things, modify Athlon Holdings LP's capital structure by replacing its different classes of interests with a single new class of units that we refer to as the "New Holdings Units." The members of our management team and certain employees that hold Class A limited partner interests of Athlon Holdings LP will own New Holdings Units and will enter into an exchange agreement under which (subject to the terms of the exchange agreement) they will have the right, under certain circumstances, to exchange their New Holdings Units for shares of common stock of Athlon Energy Inc. on a one-for-one basis, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications. All other New Holdings Units will be held by Athlon Energy Inc. Please read "Corporate Reorganization" and "Certain Relationships and Related Party Transactions—Exchange Agreement."

7

        The diagram below sets forth our simplified organizational structure after our corporate reorganization and this offering. This chart is provided for illustrative purposes only and does not represent all legal entities affiliated with us. The ownership percentages after this offering are based on an estimated valuation of Athlon using an assumed initial public offering price of $          per share, the midpoint of the price range set forth on the cover page of this propsectus.

¹

The Apollo Funds and the public stockholders will hold          % and          % of our shares of common stock, respectively, if the underwriters exercise in full their option to purchase additional shares of common stock from the Apollo Funds.

²

Borrowing base of $320 million as of July 12, 2013.

³

Co-Issuer of our 7³/8% senior notes due 2021.

⁴

Guarantors of our credit agreement and 7³/8% senior notes due 2021.

Principal Stockholders

        Our principal stockholders are the Apollo Funds. The Apollo Funds are affiliates of Apollo Global Management, LLC (together with its subsidiaries, "Apollo").

        Apollo, founded in 1990, is a leading global alternative investment manager with offices in New York, Los Angeles, Houston, London, Frankfurt, Luxembourg, Singapore, Mumbai and Hong Kong. As of March 31, 2013, Apollo had assets under management of over $114 billion in private equity, credit-oriented capital markets and real estate funds invested across a core group of nine

8

industries where Apollo has considerable knowledge and resources. Apollo's team of more than 250 seasoned investment professionals possesses a broad range of transactional, financial, managerial and investment skills, which has enabled the firm to deliver strong long-term investment performance throughout expansionary and recessionary economic cycles.

        Upon completion of this initial public offering and based on an estimated valuation of Athlon using an assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus), the Apollo Funds will beneficially own approximately          % of our common stock (or approximately          % if the underwriters' option to purchase additional shares of common stock from the Apollo Funds is exercised in full). We are also a party to certain other agreements with the Apollo Funds and certain of their affiliates. For a description of these agreements, please read "Certain Relationships and Related Party Transactions."

Corporate Information

        Our principal executive offices are located at 420 Throckmorton Street, Suite 1200, Fort Worth, Texas 76102, and our telephone number is (817) 984-8200. Our website is www.athlonenergy.com. We expect to make our periodic reports and other information filed with or furnished to the SEC available free of charge through our website as soon as reasonably practicable after those reports and other information are electronically filed with or furnished to the SEC. Information on our website or any other website is not incorporated by reference herein and does not constitute a part of this prospectus.

Emerging Growth Company Status

        We are an "emerging growth company" as defined in the Jumpstart Our Business Startups Act (the "JOBS Act"). For as long as we are an emerging growth company, unlike other public companies, we will not be required to:

•

provide an auditor's attestation report on management's assessment of the effectiveness of our system of internal control over financial reporting pursuant to Section 404 of the Sarbanes-Oxley Act of 2002 (the "Sarbanes-Oxley Act");

•

comply with any new requirements adopted by the Public Company Accounting Oversight Board, requiring mandatory audit firm rotation or a supplement to the auditor's report in which the auditor would be required to provide additional information about the audit and the financial statements of the issuer;

•

provide certain disclosure regarding executive compensation required of larger public companies; or

•

hold stockholder advisory votes on executive compensation.

        We will cease to be an emerging growth company upon the earliest of:

•

when we have $1.0 billion or more in annual revenues;

•

when we have at least $700 million in market value of our common equity securities held by non-affiliates as of any June 30;

•

when we issue more than $1.0 billion of non-convertible debt over a rolling three-year period; or

•

the last day of the fiscal year following the fifth anniversary of our initial public offering.

        As an emerging growth company, we can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. However, we have chosen to "opt out" of such extended transition period, and as a result, we will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for non-emerging growth companies. This decision is irrevocable.

9

THE OFFERING

Common stock offered by Athlon Energy Inc.	shares.
Common stock to be outstanding after the offering	shares.
New Holdings Units to be outstanding after the offering	units (                of which will be exchangeable for                 shares of our common stock).
Over-allotment option	The underwriters have a 30-day option to purchase                 shares of common stock from the Apollo Funds if the underwriters sell more than                 shares in this offering.
Use of proceeds	We expect to receive approximately $278.5 million of net proceeds from the sale of the common stock offered by us, based upon the assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus), after deducting estimated underwriting discounts and commissions and estimated offering expenses. Each $1.00 increase (decrease) in the public offering price would increase (decrease) our net proceeds by approximately $           million. We intend to use the net proceeds from this offering to purchase newly issued New Holdings Units from Athlon Holdings LP, which would subsequently use the net proceeds to repay outstanding indebtedness under our credit agreement, provide additional liquidity for use in our drilling program and for general corporate purposes, including potential acquisitions. We will not receive any proceeds from sales by the Apollo Funds pursuant to the underwriters' option to purchase additional shares of common stock.
	Affiliates of certain of the underwriters are lenders under our credit agreement and, accordingly, will receive a portion of the net proceeds from this offering. Please read "Use of Proceeds" and "Underwriting (Conflicts of Interest)."
Dividend policy	We do not anticipate paying any cash dividends on our common stock. In addition, our credit agreement and the indenture governing our senior notes place certain restrictions on our ability to pay cash dividends. Please read "Dividend Policy."
Risk factors	You should carefully read and consider the information beginning on page 18 of this prospectus set forth under the heading "Risk Factors" and all other information set forth in this prospectus before deciding to invest in our common stock.
Listing and trading symbol	We have been approved to list our common stock on the New York Stock Exchange ("NYSE") under the symbol "ATHL."

10

Conflicts of interest Apollo Global Securities, LLC is an affiliate of Apollo, our controlling stockholder. Since Apollo beneficially owns more than 10% of our outstanding common stock, a "conflict of interest" is deemed to exist under Rule 5121(f)(5)(B) of the Conduct Rules of the Financial Industry Regulatory Authority, or FINRA. In addition, if the Apollo Funds sell shares of common stock in this offering, the Apollo Funds, as selling stockholders, will likely receive more than 5% of the net proceeds of this offering, a "conflict of interest" also exists under Rule 5121(f)(5)(C)(ii). Accordingly, this offering will be made in compliance with the applicable provisions of Rule 5121. Since Apollo is not primarily responsible for managing this offering, the appointment of a "qualified independent underwriter" is not required pursuant to Rule 5121(a)(1). As such, any underwriter that has a conflict of interest pursuant to Rule 5121 will not confirm sales to accounts in which it exercises discretionary authority without the prior written consent of the customer. Please read "Underwriting (Conflicts of Interest)."

        The information above excludes                 shares of common stock initially reserved for issuance under the Athlon Energy Inc. 2013 Incentive Award Plan (which amount may be increased each year in accordance with the terms of the plan).

        If the New Holdings Units subject to the terms of the exchange agreement were exchanged in full upon completion of this offering for shares of our common stock, there would be a total of                  shares of our common stock outstanding,          % of which would be owned by purchasers in this offering (assuming the option to purchase additional shares of common stock from the Apollo Funds is not exercised).

11

SUMMARY CONSOLIDATED FINANCIAL, RESERVE AND OPERATING DATA

        The following summary consolidated financial, reserve and operating data of Athlon Holdings LP, our accounting predecessor, should be read in conjunction with, and are qualified by reference to, "Selected Historical Consolidated Financial Data," "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the consolidated financial statements and notes thereto included elsewhere in this prospectus.

        We derived the summary historical consolidated balance sheets data, statements of operations data and statements of cash flow data as of and for the years ended December 31, 2011 and 2012 of Athlon Holdings LP from the audited consolidated financial statements of Athlon Holdings LP, which are included elsewhere in this prospectus. We derived the summary historical consolidated balance sheet data as of March 31, 2013 and the historical consolidated statements of operations data and statements of cash flow data for the three months ended March 31, 2013 and 2012 of Athlon Holdings LP from the unaudited consolidated financial statements of Athlon Holdings LP, which are included elsewhere in this prospectus.

        The summary unaudited pro forma consolidated statements of operations data for the three months ended March 31, 2013 and for the year ended December 31, 2012 has been prepared to give pro forma effect to (i) our senior notes offering in April 2013, (ii) the reorganization transactions described under "Corporate Reorganization" and (iii) this offering and the application of the net proceeds from this offering as if they had been completed as of January 1, 2012. The summary unaudited pro forma consolidated balance sheet data as of March 31, 2013 has been prepared to give pro forma effect to these transactions as if they had been completed as of March 31, 2013. These data are subject and give effect to the assumptions and adjustments described in the notes accompanying the unaudited pro forma consolidated financial statements included elsewhere in this prospectus. The summary unaudited pro forma consolidated financial data are presented for informational purposes only and should not be considered indicative of actual results of operations that would have been achieved had the senior notes offering, the reorganization transactions and this offering been consummated on the dates indicated, and do not purport to be indicative of statements of financial position or results of operations as of any future date or for any future period.

12

Summary Consolidated Financial Data

						Historical Athlon Holdings LP
	Pro Forma Athlon Energy Inc.
						Three months ended March 31,						Year ended December 31,
	Three months ended March 31, 2013
			Year ended December 31, 2012
						2013			2012			2012			2011
	(unaudited)					(unaudited)
	(in thousands, except per share data)
Consolidated Statements of Operations Data:
Revenues:
Oil	$	45,659	$	128,081		$	45,659		$	27,433		$	128,081		$	51,193
Natural gas		3,367		8,415			3,367			1,448			8,415			3,521
NGLs		5,720		20,615			5,720			4,351			20,615			10,967
Total revenues		54,746		157,111			54,746			33,232			157,111			65,681
Expenses:
Production:
Lease operating		7,237		25,503			7,237			4,699			25,503			13,328
Production, severance and ad valorem taxes		3,694		10,438			3,694			2,350			10,438			4,727
Depletion, depreciation and amortization		18,053		54,456			18,053			9,614			54,456			19,747
General and administrative		3,282		9,678			3,282			2,597			9,678			7,724
Acquisition costs		57		876			57			—			876			9,519
Derivative fair value loss (gain)		6,849		(9,293	)		6,849			22,711			(9,293	)		7,959
Other operating		194		562			194			130			562			404
Total expenses		39,366		92,220			39,366			42,101			92,220			63,408
Operating income (loss)		15,380		64,891			15,380			(8,869	)		64,891			2,273
Interest expense		9,976		40,590			4,474			1,495			9,949			2,932
Income (loss) before income taxes		5,404		24,301			10,906			(10,364	)		54,942			(659	)
Income tax provision (benefit)		2,021		9,086			27			(364	)		1,928			470
Consolidated net income (loss)		3,383		15,215			10,879			(10,000	)		53,014			(1,129	)
Less: net income (loss) attributable to noncontrolling interest		168		753			—			—			—			—
Net income (loss) attributable to stockholders	$	3,215	$	14,462		$	10,879		$	(10,000	)	$	53,014		$	(1,129	)
Net income (loss) per common share:
Basic	$	*	$	*
Diluted	$	*	$	*
Weighted average common shares outstanding:
Basic		*		*
Diluted		*		*
Consolidated Statements of Cash Flows Data:
Cash provided by (used in):
Operating activities						$	30,397		$	20,723		$	95,302		$	18,872
Investing activities							(90,560	)		(58,498	)		(347,259	)		(465,475	)
Financing activities							54,671			12,982			228,798			471,627
Consolidated Balance Sheets Data (at period end):
Cash and cash equivalents	$	275,103				$	3,379					$	8,871		$	32,030
Total assets		1,197,926					916,535						852,298			561,823
Total debt		500,000					416,426						362,000			170,000
Total equity		612,848					433,330						420,877			327,452
Other Financial Data:
Adjusted EBITDA1	$	40,669	$	111,160		$	40,669		$	21,171		$	111,160		$	31,469
Development capital							71,791			49,241			276,182			89,232

*

To be completed by amendment.

¹

Adjusted EBITDA is a non-GAAP financial measure. For a definition of Adjusted EBITDA and a reconciliation to our most directly comparable financial measures calculated and presented in accordance with GAAP, please read "—Non-GAAP Financial Measures."

13

Summary Reserve Data

        The following table presents summary data with respect to our estimated net proved reserves as of the dates indicated. The reserve estimates presented in the table below are based on proved reserve reports prepared by CG&A, our independent petroleum engineers, in accordance with the rules and regulations of the SEC regarding oil and natural gas reserve reporting. For more information about our proved reserves as of December 31, 2012 and 2011, please read CG&A's proved reserve reports, which have been filed as exhibits to the registration statement of which this prospectus is a part.

	December 31,
	2012			2011
Reserves Data1:
Estimated proved reserves:
Oil (MBbls)		49,423			25,972
Natural gas (MMcf)		103,683			51,560
NGLs (MBbls)		19,275			11,549
Total estimated proved reserves (MBOE)		85,979			46,114
Proved developed reserves (MBOE)		25,698			13,496
% proved developed		30	%		29	%
Proved undeveloped reserves (MBOE)		60,281			32,618
PV-10 of proved reserves (in millions)2	$	866.6		$	591.4
Standardized Measure (in millions)3	$	850.9		$	581.2

¹

Our estimated proved reserves and related future net revenues, PV-10 and Standardized Measure were determined using index prices for oil and natural gas, without giving effect to commodity derivative contracts, and were held constant throughout the life of the properties. The unweighted arithmetic average first-day-of-the-month prices for the prior 12 months were $94.71 per Bbl for oil and $2.75 per Mcf for natural gas at December 31, 2012 and $96.19 per Bbl for oil and $4.11 per Mcf for natural gas at December 31, 2011. These prices were adjusted by lease for quality, transportation fees, historical geographic differentials, marketing bonuses or deductions and other factors affecting the price received at the wellhead.

²

PV-10 is a non-GAAP financial measure and generally differs significantly from Standardized Measure, the most directly comparable GAAP financial measure, because it does not include the effects of federal income taxes on future net revenues. As of December 31, 2012 and 2011, our accounting predecessor was a limited partnership not subject to federal income taxes. Accordingly, no provision for federal income taxes has been provided for in our Standardized Measure because taxable income was passed through to its partners. However, the PV-10 and the Standardized Measure differ as a result of the Texas margin tax. Had we been a Subchapter C Corporation subject to federal income taxation, our Standardized Measure would have been $602.5 million and $428.5 million as of December 31, 2012 and 2011, respectively, on a pro forma basis. Neither PV-10 nor Standardized Measure represents an estimate of the fair market value of our proved reserves. We and others in the industry use PV-10 as a measure to compare the relative size and value of proved reserves held by companies without regard to the specific tax characteristics of such entities. Please read "—Non-GAAP Financial Measures."

³

Standardized Measure represents the present value of estimated future cash inflows from proved reserves, less future development, production and income tax expenses, discounted at 10% per annum to reflect timing of future cash flows.

Non-GAAP Financial Measures

Adjusted EBITDA

        We include in this prospectus the non-GAAP financial measure Adjusted EBITDA. We provide a reconciliation of Adjusted EBITDA to its most directly comparable financial measures as calculated and presented in accordance with GAAP.

        We define Adjusted EBITDA as consolidated net income (loss):

Plus:

•

Interest expense;

•

Income tax provision;

14

•

Depreciation, depletion and amortization;

•

Acquisition costs;

•

Advisory fees;

•

Non-cash equity-based compensation expense;

•

Non-cash mark-to-market losses on derivative contracts;

•

Accretion of discount on asset retirement obligations;

•

Impairment of oil and natural gas properties, if any; and

•

Other non-cash operating items.

Less:

•

Interest income;

•

Income tax benefit; and

•

Non-cash mark-to-market gains on derivative contracts.

        Adjusted EBITDA is used as a supplemental financial measure by management and by external users of our consolidated financial statements, such as investors, lenders under our credit agreement, commercial banks, research analysts and others, to assess:

•

the financial performance of our assets without regard to financing methods, capital structure or historical cost basis;

•

our operating performance and return on capital as compared to those of other companies in the upstream energy sector, without regard to financing or capital structure; and

•

the attractiveness of capital projects and acquisitions and the overall rates of return on alternative investment opportunities.

        The GAAP measures most directly comparable to Adjusted EBITDA are cash flows provided by operating activities and consolidated net income (loss). Adjusted EBITDA should not be considered as an alternative to cash flows provided by operating activities or consolidated net income (loss). Adjusted EBITDA may not be comparable to similar measures used by other companies. You should not consider Adjusted EBITDA in isolation or as a substitute for analysis of our results as reported under GAAP. Adjusted EBITDA has limitations as an analytical tool and should not be considered as an alternative to, or more meaningful than, performance measures calculated in accordance with GAAP. Some of these limitations are:

•

certain items excluded from Adjusted EBITDA are significant components in understanding and assessing a company's financial performance, such as a company's cost of capital and tax structure, as well as the historical costs of depreciable assets;

•

Adjusted EBITDA does not reflect our cash expenditures or future requirements for capital expenditures or contractual commitments;

•

Adjusted EBITDA does not reflect changes in, or cash requirements for, our working capital needs;

•

although depreciation, depletion and amortization are non-cash charges, the assets being depreciated, depleted and amortized will often have to be replaced in the future, and Adjusted EBITDA does not reflect any cash requirements for such replacements; and

•

our computation of Adjusted EBITDA may not be comparable to other similarly titled measures of other companies.

15

        Management compensates for the limitations of Adjusted EBITDA as an analytical tool by reviewing the comparable GAAP measures, understanding the differences between the measures and incorporating these data points into their decision-making process.

        The following table presents a reconciliation of Adjusted EBITDA to the GAAP financial measure of consolidated net income (loss):

						Historical Athlon Holdings LP
	Pro Forma Athlon Energy Inc.
						Three months ended March 31,					Year ended December 31,
	Three months ended March 31, 2013
			Year ended December 31, 2012
						2013		2012			2012			2011
	(in thousands)
Consolidated net income (loss)	$	3,383	$	15,215		$	10,879	$	(10,000	)	$	53,014		$	(1,129	)
Interest expense		9,976		40,590			4,474		1,495			9,949			2,932
Income tax provision (benefit)		2,021		9,086			27		(364	)		1,928			470
Depreciation, depletion and amortization		18,053		54,456			18,053		9,614			54,456			19,747
Acquisition costs		57		876			57		—			876			9,519
Advisory fees1		405		493			405		213			493			411
Non-cash equity-based compensation		48		152			48		58			152			106
Non-cash mark-to-market derivative loss (gain)2		6,531		(10,367	)		6,531		20,013			(10,367	)		(2,400	)
Accretion3		149		478			149		106			478			344
Other non-cash operating items4		46		181			46		36			181			1,469
Adjusted EBITDA	$	40,669	$	111,160		$	40,669	$	21,171		$	111,160		$	31,469

¹

Represents the annual advisory fee paid to affiliates of Apollo pursuant to a Services Agreement. The Services Agreement will be terminated in connection with this offering. Please read "Certain Relationships and Related Party Transactions."

²

Represents the adjustment necessary to reflect derivative gains and losses on a realized cash basis in the period the derivatives settle rather than the period the unrealized mark-to-market gains and losses were recognized in earnings. Unrealized gains (losses) included on the consolidated balance sheet at March 31, 2013, March 31, 2012, December 31, 2012 and December 31, 2011 were approximately $4.0 million, $27.8 million, $(2.6) million and $(7.8) million, respectively. Realized gains (losses) for the quarters ended March 31, 2013 and 2012 and the years ended December 31, 2012 and 2011 were approximately $35,000, $(2.5) million, $(234,000) and $(2.7) million, respectively. The net cash receipts (payments) related to derivative settlements for the quarters ended March 31, 2013 and 2012 and the years ended December 31, 2012 and 2011 were approximately $(141,000), $(2.6) million, $(654,000) and $7.2 million, respectively. Please read "Management's Discussion and Analysis of Financial Condition and Results of Operations—Quantitative and Qualitative Disclosures About Market Risk" for additional discussion of our derivatives.

³

Represents the non-cash accretion of the discount on asset retirement obligations.

⁴

Includes deferred rent expenses and non-cash LOE.

        The following table presents a reconciliation of Adjusted EBITDA to the GAAP financial measure of cash flows provided by operating activities:

	Historical Athlon Holdings LP
	Three months ended March 31,						Year ended December 31,
	2013			2012			2012			2011
	(in thousands)
Adjusted EBITDA	$	40,669		$	21,171		$	111,160		$	31,469
Changes in operating assets and liabilities		(5,579	)		1,102			(5,639	)		1,115
Acquisition costs		(57	)		—			(876	)		(9,519	)
Non-cash LOE		—			—			—			(1,159	)
Cash interest expense		(4,231	)		(1,337	)		(8,850	)		(2,623	)
Advisory fees1		(405	)		(213	)		(493	)		(411	)
Cash flows provided by operating activities	$	30,397		$	20,723		$	95,302		$	18,872

¹

Represents the annual advisory fee paid to affiliates of Apollo pursuant to a Services Agreement. The Services Agreement will be terminated in connection with this offering. Please read "Certain Relationships and Related Party Transactions."

16

PV-10

        PV-10 is a non-GAAP financial measure and is derived from Standardized Measure, which is the most directly comparable GAAP financial measure. PV-10 is equal to the Standardized Measure of discounted future net cash flows at the applicable date, before deducting future income taxes, discounted at 10%. We believe that the presentation of PV-10 is relevant and useful to investors because it presents the relative monetary significance of our properties regardless of tax structure. Further, investors may utilize the measure as a basis for comparison of the relative size and value of our proved reserves to other companies. We use this measure when assessing the potential return on investment related to our oil, natural gas and NGL properties. However, PV-10 is not equal to, nor a substitute for, the Standardized Measure of discounted future net cash flows. Our PV-10 and the Standardized Measure of discounted future net cash flows do not purport to present the fair value of our proved reserves. The following table provides a reconciliation of PV-10 to the GAAP financial measure of Standardized Measure as of December 31, 2012 and 2011:

	As of December 31,
	2012			2011
	(in millions)
PV-10 of proved reserves	$	866.6		$	591.4
Present value of future income tax discounted at 10%		(15.7	)		(10.2	)
Standardized Measure	$	850.9		$	581.2

Summary Operating Data

        The following table sets forth summary data with respect to our production results, average realized prices and certain expenses on a per BOE basis for the periods presented:

	Three months ended March 31,				Year ended December 31,
	2013		2012		2012		2011
Total production volumes:
Oil (MBbls)		542		276		1,457		556
Natural gas (MMcf)		1,030		534		3,163		1,017
NGLs (MBbls)		183		102		595		239
Combined (MBOE)		896		468		2,579		964
Average daily production volumes:
Oil (Bbls/D)		6,023		3,036		3,981		1,523
Natural gas (Mcf/D)		11,446		5,871		8,641		2,786
NGLs (Bbls/D)		2,028		1,125		1,625		654
Combined (BOE/D)		9,959		5,140		7,047		2,641
Average realized prices:
Oil ($/Bbl) (excluding impact of cash settled derivatives)	$	84.23	$	99.29	$	87.90	$	92.08
Oil ($/Bbl) (after impact of cash settled derivatives)		83.97		89.91		87.45		91.27
Natural gas ($/Mcf)		3.27		2.71		2.66		3.46
NGLs ($/Bbl)		31.34		42.48		34.65		45.96
Combined ($/BOE) (excluding impact of cash settled derivatives)		61.08		71.05		60.91		68.13
Combined ($/BOE) (after impact of cash settled derivatives)		60.92		65.50		60.66		67.66
Expenses (per BOE):
Lease operating	$	8.07	$	10.05	$	9.89	$	13.82
Production, severance and ad valorem taxes		4.12		5.03		4.05		4.90
Depletion, depreciation and amortization		20.14		20.55		21.11		20.48
General and administrative		3.73		5.55		3.75		8.01

17

RISK FACTORS

An investment in our common stock involves a high degree of risk. You should carefully consider the following risks and all of the other information contained in this prospectus before deciding to invest in our common stock. Our business, financial condition and results of operations could be materially and adversely affected by any of these risks. The risks described below are not the only ones facing us. Additional risks not presently known to us or which we consider immaterial also may adversely affect us.

Risks Related to the Oil and Natural Gas Industry and Our Business

Our business is difficult to evaluate because we have a limited operating history.

        Athlon Holdings LP was formed in July 2011 and became the sole owner of Athlon Energy LP, which began operating our first properties after acquiring them in January 2011. As a result, there is only limited historical financial and operating information available upon which to base your evaluation of our performance.

Drilling for and producing oil and natural gas are high-risk activities with many uncertainties that may result in a total loss of investment or otherwise adversely affect our business, financial condition or results of operations.

        Our drilling activities are subject to many risks. For example, we cannot assure you that wells drilled by us will be productive or that we will recover all or any portion of our investment in such wells. Drilling for oil and natural gas often involves unprofitable efforts, not only from dry holes but also from wells that are productive but do not produce sufficient oil or natural gas to return a profit at then-realized prices after deducting drilling, operating and other costs. The seismic data and other technologies we use do not allow us to know conclusively prior to drilling a well that oil or natural gas is present or that it can be produced economically. The costs of exploration, exploitation and development activities are subject to numerous uncertainties beyond our control, and increases in those costs can adversely affect the economics of a project. In addition, the application of new techniques for us such as horizontal drilling, which we have not previously employed, may make it more difficult to accurately estimate these costs. Further, our drilling and producing operations may be curtailed, delayed, canceled or otherwise negatively impacted as a result of other factors, including:

•

unusual or unexpected geological formations;

•

loss of drilling fluid circulation;

•

title problems;

•

facility or equipment malfunctions;

•

unexpected operational events;

•

shortages or delivery delays or increases in the cost of equipment and services;

•

reductions in oil and natural gas prices;

•

lack of proximity to and shortage of capacity of transportation facilities;

•

the limited availability of financing at acceptable rates;

•

delays imposed by or resulting from compliance with environmental and other governmental or regulatory requirements, which may include limitations on hydraulic fracturing or the discharge of greenhouse gases; and

•

adverse weather conditions.

18

        Any of these risks can cause substantial losses, including personal injury or loss of life, damage to or destruction of property, natural resources and equipment, pollution, environmental contamination or loss of wells and other regulatory penalties.

Our development and exploratory drilling efforts and our well operations may not be profitable or achieve our targeted returns.

        We have acquired significant amounts of unproved property in order to further our development efforts and expect to continue to undertake acquisitions in the future. Development and exploratory drilling and production activities are subject to many risks, including the risk that no commercially productive reservoirs will be discovered. We acquire unproved properties and lease undeveloped acreage that we believe will enhance our growth potential and increase our results of operations over time. However, we cannot assure you that all prospects will be economically viable or that we will not abandon our investments. Additionally, we cannot assure you that unproved property acquired by us or undeveloped acreage leased by us will be profitably developed, that wells drilled by us in prospects that we pursue will be productive or that we will recover all or any portion of our investment in such unproved property or wells.

We may have difficulty managing growth in our business, which could adversely affect our financial condition and results of operations.

        As a recently formed company, growth in accordance with our business plan, if achieved, could place a significant strain on our financial, technical, operational and management resources. As we expand our activities and increase the number of projects we are evaluating or in which we participate, there will be additional demands on our financial, technical, operational and management resources. The failure to continue to upgrade our technical, administrative, operating and financial control systems or the occurrences of unexpected expansion difficulties, including the failure to recruit and retain experienced managers, geologists, engineers and other professionals in the oil and natural gas industry, could have a material adverse effect on our business, financial condition and results of operations and our ability to timely execute our business plan.

As of May 31, 2013, approximately 45% of our net leasehold acreage is undeveloped, and that acreage may not ultimately be developed or become commercially productive, which could cause us to lose rights under our leases as well as have a material adverse effect on our reserves and future production and, therefore, our future cash flow and income.

        As of May 31, 2013, approximately 45% of our net leasehold acreage is undeveloped, or acreage on which wells have not been drilled or completed to a point that would permit the production of commercial quantities of hydrocarbons regardless of whether such acreage contains proved reserves. In addition, many of our oil and natural gas leases require us to drill wells that are commercially productive, and if we are unsuccessful in drilling such wells, we could lose our rights under such leases. Our reserves and future production and, therefore, our future cash flow and income are highly dependent on successfully developing our undeveloped leasehold acreage.

Our development and exploration operations require substantial capital and we may be unable to obtain needed capital or financing on satisfactory terms or at all, which could lead to a loss of properties and a decline in our reserves.

        The oil and natural gas industry is capital intensive. We make and expect to continue to make substantial capital expenditures in our business and operations for the exploration for and development, production and acquisition of reserves. In 2012, our total development capital was approximately $276 million and expenditures for leasehold interest and property acquisitions were approximately $81 million. Our 2013 development capital budget for drilling, completion and infrastructure, including investments in water disposal infrastructure and gathering line projects, is approximately $350 million.

19

To date, we have financed capital expenditures primarily with funding from the Apollo Funds, our equity sponsor, borrowings under our credit agreement and cash flows from operations. Notwithstanding prior contributions to us by the Apollo Funds or their affiliates, you should not assume that any of them will provide any debt or equity funding to us in the future.

        In the near term, we intend to finance our capital expenditures with cash flows from operations and borrowings under our credit agreement. Our cash flows from operations and access to capital are subject to a number of variables, including:

•

our proved reserves;

•

the volume of hydrocarbons we are able to produce from existing wells;

•

the prices at which our production is sold;

•

the levels of our operating expenses; and

•

our ability to acquire, locate and produce new reserves.

        We cannot assure you that our operations and other capital resources will provide cash in sufficient amounts to maintain planned or future levels of capital expenditures. Further, our actual capital expenditures in 2013 could exceed our budget. In the event our capital expenditure requirements at any time are greater than the amount of capital we have available, we could be required to seek additional sources of capital, which may include traditional reserve base borrowings, debt financing, joint ventures, production payment financings, sales of assets, private or public offerings of debt or equity securities or other means. Our ability to access the private and public debt or equity markets is dependent upon a number of factors outside our control, including oil and natural gas prices as well as economic conditions in the financial markets. We cannot assure you that we will be able to obtain debt or equity financing on terms favorable to us, or at all.

        Our business and operating results can be harmed by factors such as the availability, terms and cost of capital, increases in interest rates or a reduction in our credit rating. Changes in any one or more of these factors could cause our cost of doing business to increase, limit our access to capital, limit our ability to pursue acquisition opportunities, reduce our cash flows available for drilling and place us at a competitive disadvantage. In addition, our ability to access the private and public debt or equity markets is dependent upon a number of factors outside our control, including oil and natural gas prices as well as economic conditions in the financial markets. Continuing disruptions and volatility in the global financial markets may lead to an increase in interest rates or a contraction in credit availability impacting our ability to finance our operations. We cannot assure you that we will be able to obtain debt or equity financing on terms favorable to us, or at all.

        If we are unable to fund our capital requirements, we may be required to curtail our operations relating to the exploration and development of our prospects, which in turn could lead to a possible loss of properties and a decline in our reserves, or may be otherwise unable to implement our development plan, complete acquisitions or otherwise take advantage of business opportunities or respond to competitive pressures, any of which could have a material adverse effect on our production, revenues and results of operations. In addition, a delay in or the failure to complete proposed or future infrastructure projects could delay or eliminate potential efficiencies and related cost savings.

Our success depends on finding, developing or acquiring additional reserves. Unless we replace our oil and natural gas reserves, our reserves and production will decline, which would adversely affect our business, financial condition and results of operations.

        Our future oil and natural gas reserves and production, and therefore our cash flows and income, highly depend on our ability to find, develop or acquire additional reserves that are economically recoverable. Our proved reserves will generally decline as reserves are depleted, except to the extent that we conduct successful exploration or development activities or acquire properties containing

20

proved reserves, or both. To increase reserves and production, we undertake development, exploration and other replacement activities or use third parties to accomplish these activities. We have made, and expect to make in the future, substantial capital expenditures in our business and operations for the development, production, exploration and acquisition of reserves. We may not have sufficient resources to undertake our exploration, development and production activities. In addition, the acquisition of reserves, our exploratory projects and other replacement activities may not result in significant additional reserves and we may not have success drilling productive wells at low finding and development costs. Furthermore, although our revenues may increase if prevailing commodity prices increase, our finding costs for additional reserves could also increase.

Our project areas, which are in various stages of development, may not yield oil or natural gas in commercially viable quantities.

        Our project areas are in various stages of development, ranging from project areas with current drilling or production activity to project areas that consist of recently acquired leasehold acreage or that have limited drilling or production history. From the time we began operations in January 2011 through May 31, 2013, we have drilled a total of 230 gross (220 net) wells and participated in an additional 8 gross (3 net) non-operated wells. In total, 216 gross (202 net) of these wells were completed as producing wells and 3 gross (3 net) wells were abandoned as dry holes. At May 31, 2013, 19 gross (19 net) wells were in various stages of completion. If the wells in the process of being completed do not produce sufficient revenues to return a profit or if we drill dry holes in the future, our business may be materially affected.

Our identified potential drilling locations, which are scheduled out over many years, are susceptible to uncertainties that could materially alter the occurrence or timing of their drilling.

        As of May 31, 2013, we had identified 2,298 gross (1,797 net) potential vertical drilling locations on our existing acreage based on 40-acre spacing and an additional 2,604 gross (2,060 net) potential vertical drilling locations based on 20-acre spacing. Only 597 gross (560 net) of these potential vertical drilling locations were attributed to PUDs in our December 31, 2012 reserve report. These drilling locations, including those without PUDs, represent a significant part of our growth strategy. Our ability to drill and develop these locations depends on a number of uncertainties, including the availability of capital, construction of infrastructure, inclement weather, regulatory changes and approvals, commodity prices, lease expirations, our ability to secure rights to drill at deeper formations, costs and drilling results.

        Further, our identified potential drilling locations are in various stages of evaluation, ranging from locations that are ready to drill to locations that will require substantial additional analysis of data. We cannot predict in advance of drilling and testing whether any particular drilling location will yield oil or natural gas reserves in sufficient quantities to recover drilling or completion costs or to be economically viable or whether wells drilled on 20-acre spacing will produce at the same rates as those on 40-acre spacing. The use of reliable technologies and the study of producing fields in the same area will not enable us to know conclusively prior to drilling whether oil or natural gas reserves will be present or, if present, whether oil or natural gas reserves will be present in sufficient quantities to be economically viable. Even if sufficient amounts of oil or natural gas reserves exist, we may damage the potentially productive hydrocarbon bearing formation or experience mechanical difficulties while drilling or completing the well, possibly resulting in a reduction in production from the well or abandonment of the well. If we drill dry holes in our current and future drilling locations, our drilling success rate may decline and materially harm our business. We cannot assure you that the analogies we draw from available data from other wells, more fully explored locations or producing fields will be applicable to our drilling locations. Further, initial production rates reported by us or other operators in the Permian Basin may not be indicative of future or long-term production rates.

21

        Because of these uncertainties, we do not know if the potential drilling locations we have identified will ever be drilled or if we will be able to produce oil or natural gas reserves from these or any other potential drilling locations. As such, our actual drilling activities may materially differ from those presently identified, which could adversely affect our business, financial condition and results of operations.

The development of our PUDs may take longer and may require higher levels of capital expenditures than we anticipate and may not be economically viable.

        Approximately 70% of our total proved reserves at December 31, 2012 were PUDs and may not be ultimately developed or produced. Recovery of PUDs requires significant capital expenditures and successful drilling operations. The reserve data included in the independent petroleum engineering firm's proved reserve report assumes that substantial capital expenditures are required to develop such reserves. We cannot be certain that the estimated costs of the development of these reserves are accurate, that development will occur as scheduled or that the results of such development will be as estimated. Delays in the development of our reserves or increases in costs to drill and develop such reserves will reduce future net revenues of our estimated PUDs and may result in some projects becoming uneconomic. In addition, delays in the development of reserves could cause us to have to reclassify our proved reserves as PUDs.

Our acreage must be drilled before lease expiration, generally within three to five years, in order to hold the acreage by production. In a highly competitive market for acreage, failure to drill sufficient wells to hold acreage may result in a substantial lease renewal cost, or if renewal is not feasible, loss of our lease and prospective drilling opportunities.

        Leases on oil and natural gas properties typically have a term of three to five years, after which they expire unless, prior to expiration, production is established within the spacing units covering the undeveloped acres. As of May 31, 2013, we had leases representing 9,639 gross (7,653 net) acres scheduled to expire in 2013, 5,362 gross (4,257 net) acres scheduled to expire in 2014, 9,213 gross (7,363 net) acres scheduled to expire in 2015, 27,224 gross (21,049 net) acres scheduled to expire in 2016 and no net acres scheduled to expire in 2017. The cost to renew such leases may increase significantly, and we may not be able to renew such leases on commercially reasonable terms or at all. Moreover, many of our leases require lessor consent to pool, which may make it more difficult to hold our leases by production. Any reduction in our current drilling program, either through a reduction in capital expenditures or the unavailability of drilling rigs, could result in the loss of acreage through lease expirations. In addition, in order to hold our current leases scheduled to expire in 2014 and 2015, we will need to operate at least a three-rig program. We cannot assure you that we will have the liquidity to deploy these rigs when needed, or that commodity prices will warrant operating such a drilling program. Any such losses of leases could materially and adversely affect the growth of our asset base, cash flows and results of operations.

The unavailability, high cost or shortages of rigs, equipment, raw materials, supplies or personnel may restrict our operations.

        The oil and natural gas industry is cyclical, which can result in shortages of drilling rigs, equipment, raw materials (particularly sand and other proppants), supplies and personnel. When shortages occur, the costs and delivery times of rigs, equipment and supplies increase and demand for, and wage rates of, qualified drilling rig crews also rise with increases in demand for oil and natural gas. In accordance with customary industry practice, we rely on independent third-party service providers to provide most of the services necessary to drill new wells. If we are unable to secure a sufficient number of drilling rigs at reasonable costs, our financial condition and results of operations could suffer, and we may not be able to drill all of our acreage before our leases expire. In addition, we do not have long-term contracts securing the use of our existing rigs, and the operator of those rigs may choose to cease providing services to us. We are currently operating seven vertical drilling rigs across our

22

properties and we expect to take delivery of our first horizontal rig in the third quarter of 2013. In 2014, we intend to expand to an eight-rig vertical drilling program. Shortages of drilling rigs, equipment, raw materials (particularly sand and other proppants), supplies, drilling rig crews and other personnel, trucking services, tubulars, fracking and completion services and production equipment, including equipment and personnel related to horizontal drilling activities, could delay or restrict our exploration and development operations, which in turn could impair our financial condition and results of operations.

The volatility of oil and natural gas prices due to factors beyond our control greatly affects our profitability.

        Our revenues, operating results, profitability, future rate of growth and the carrying value of our oil and natural gas properties depend primarily upon the prevailing commodity prices. Historically, oil and natural gas prices have been volatile and are subject to fluctuations in response to changes in supply and demand, market uncertainty and a variety of additional factors that are beyond our control, including:

•

the regional, domestic and foreign supply of oil and natural gas;

•

the level of commodity prices and expectations about future commodity prices;

•

the level of global oil and natural gas exploration and production;

•

localized supply and demand fundamentals, including the proximity and capacity of oil and natural gas pipelines and other transportation facilities, and other factors that result in differentials to benchmark prices from time to time;

•

the cost of exploring for, developing, producing and transporting reserves;

•

the price of foreign imports;

•

political and economic conditions in oil producing countries;

•

the ability of members of the Organization of Petroleum Exporting Countries to agree to and maintain oil price and production controls;

•

speculative trading in crude oil and natural gas derivative contracts;

•

the level of consumer product demand;

•

weather conditions and other natural disasters;

•

risks associated with operating drilling rigs;

•

technological advances affecting exploration and production operations and overall energy consumption;

•

domestic and foreign governmental regulations and taxes;

•

the continued threat of terrorism and the impact of military and other action, including U.S. military operations in the Middle East;

•

the price and availability of competitors' supplies of oil and natural gas and alternative fuels; and

•

overall domestic and global economic conditions.

        These factors and the volatility of the energy markets make it extremely difficult to predict future oil and natural gas price movements with any certainty. For example, during the past five years, the NYMEX prompt month contract price for WTI has ranged from a low of $33.87 per Bbl in December 2008 to a high of $145.29 per Bbl in July 2008, and the Henry Hub prompt month contract price of natural gas has ranged from a low of $1.91 per MMBtu in April 2012 to a high of $13.58 per MMBtu

23

in July 2008. During the first quarter of 2013, WTI prompt month contract ranged from $90.12 to $97.94 per Bbl and the Henry Hub prompt month contract price of natural gas ranged from $3.11 to $4.07 per MMBtu. During 2012, WTI prompt month contract ranged from $77.69 to $109.77 per Bbl and the Henry Hub prompt month contract price of natural gas ranged from $1.91 to $3.90 per MMBtu. On March 31, 2013, the WTI prompt month contract price for crude oil was $97.23 per Bbl and the Henry Hub prompt month contract price of natural gas was $4.02 per MMBtu. Any substantial decline in commodity prices will likely have a material adverse effect on our operations, financial condition and level of expenditures for the development of our reserves.

        As of December 31, 2012, NGLs comprised 22% of our estimated proved reserves and accounted for 23% of our 2012 production at an average price of $34.65 per Bbl, a 25% drop in average price from the prior year. Further, realized NGL prices have decreased principally due to significant supply. The terms of our sale contracts allow purchasers of our production to decline to purchase our produced ethane and instead pay dry natural gas prices for the ethane that we produce in the gas stream. NGLs are made up of ethane, propane, isobutane, normal butane and natural gasoline, all of which have different uses and different pricing characteristics. A further or extended decline in NGL prices could materially and adversely affect our future business, financial condition and results of operations.

        Substantially all of our production is sold to purchasers under contracts with market-based prices. Moreover, all of our oil contracts include the Midland-Cushing differential (the difference between Midland WTI and Cushing WTI), which widened in 2012 and in early 2013 due to difficulty transporting oil production from the Permian Basin to the Gulf Coast refineries as a result of lack of logistics and infrastructure. The Midland-Cushing differential has since narrowed. We may experience differentials to NYMEX in the future, which may be material. Lower oil, natural gas and NGL prices will reduce our cash flows and the present value of our reserves. If oil, natural gas and NGL prices deteriorate, we anticipate that the borrowing base under our credit agreement, which is revised periodically, may be reduced, which would negatively impact our borrowing ability. Additionally, prices could reduce our cash flows to a level that would require us to borrow to fund our current or future capital budgets. Lower oil, natural gas and NGL prices may also reduce the amount of oil, natural gas and NGLs that we can produce economically. Substantial decreases in oil, natural gas and NGL prices could render uneconomic a significant portion of our identified drilling locations. This may result in significant downward adjustments to our estimated proved reserves. If this occurs or if our production estimates change or our exploration or development results deteriorate, full cost accounting rules may require us to write down, as a non-cash charge to earnings, the carrying value of our oil and natural gas properties. As a result, a substantial or extended decline in oil, natural gas or NGL prices may materially and adversely affect our future business, financial condition, results of operations, liquidity or ability to finance planned capital expenditures.

We have entered into oil derivative contracts and may in the future enter into additional commodity derivative contracts for a portion of our production, which may result in future cash payments or prevent us from receiving the full benefit of increases in commodity prices.

        We use commodity derivative contracts to reduce price volatility associated with certain of our oil sales. Under these contracts, we receive a fixed price per Bbl of oil and pay a floating market price per Bbl of oil to the counterparty based on NYMEX WTI pricing. The fixed-price payment and the floating-price payment are offset, resulting in a net amount due to or from the counterparty. The extent of our commodity price exposure is related largely to the effectiveness and scope of our commodity derivative contracts. For example, some of the commodity derivative contracts we utilize are based on quoted market prices, which may differ significantly from the actual prices we realize in our operations for oil. In addition, our credit agreement limits the aggregate notional volume of commodities that can be covered under commodity derivative contracts we can enter into and, as a result, we will continue to have direct commodity price exposure on the unhedged portion of our production volumes. As of March 31, 2013, we have oil swaps covering: 6,000 Bbls/D at a weighted-

24

average price of $94.66 per Bbl for 2013; 5,950 Bbls/D at a weighted-average price of $92.76 per Bbl for 2014; and 1,300 Bbls/D at a weighted-average price of $93.18 per Bbl for 2015. We also have oil collars covering 150 Bbls/D for 2013 containing floors of $75.00 per Bbl and ceilings of $105.95 per Bbl. Our policy has been to hedge a significant portion of our estimated oil production. However, our price hedging strategy and future hedging transactions will be determined at our discretion. We are not under an obligation to hedge a specific portion of our production. The prices at which we hedge our production in the future will be dependent upon commodity prices at the time we enter into these transactions, which may be substantially higher or lower than current commodity prices. Accordingly, our price hedging strategy may not protect us from significant declines in commodity prices received for our future production, whether due to declines in prices in general or to widening differentials we experience with respect to our products. Conversely, our hedging strategy may limit our ability to realize cash flows from commodity price increases. It is also possible that a substantially larger percentage of our future production will not be hedged as compared with the next few years, which would result in our revenues becoming more sensitive to commodity price changes.

        In addition, our actual future production may be significantly higher or lower than we estimate at the time we enter into commodity derivative contracts for such period. If the actual amount is higher than we estimate, we will have greater commodity price exposure than we intended. If the actual amount is lower than the notional amount of our commodity derivative contracts, we might be forced to satisfy all or a portion of our commodity derivative contracts without the benefit of the cash flow from our sale or purchase of the underlying physical commodity, substantially diminishing our liquidity. There may be a change in the expected differential between the underlying commodity price in the commodity derivative contract and the actual price received, which may result in payments to our derivative counterparty that are not offset by our receipt of payments for our production in the field. Accordingly, our earnings may fluctuate significantly as a result of changes in the fair value of our commodity derivative contracts.

Our commodity derivative contracts expose us to counterparty credit risk.

        Our commodity derivative contracts expose us to risk of financial loss if a counterparty fails to perform under a contract. Disruptions in the financial markets could lead to sudden decreases in a counterparty's liquidity, which could make them unable to perform under the terms of the contract and we may not be able to realize the benefit of the contract. We are unable to predict sudden changes in a counterparty's creditworthiness or ability to perform. Even if we do accurately predict sudden changes, our ability to negate the risk may be limited depending upon market conditions.

        During periods of declining commodity prices, our derivative contract receivable positions generally increase, which increases our counterparty credit exposure. If the creditworthiness of our counterparties deteriorates and results in their nonperformance, we could incur a significant loss with respect to our commodity derivative contracts.

The inability of one or more of our customers to meet their obligations may adversely affect our financial results.

        In addition to credit risk related to receivables from commodity derivative contracts, our principal exposure to credit risk is through receivables from purchasers of our oil and natural gas production. For 2012, three purchasers accounted for more than 10% of our revenues: Pecos Gathering & Marketing (43%); Occidental Petroleum Corporation (29%); and DCP Midstream (12%). This concentration of customers may impact our overall credit risk in that these entities may be similarly affected by changes in economic and other conditions. Current economic circumstances may further increase these risks. We do not require our customers to post collateral. The inability or failure of our significant customers to meet their obligations to us or their insolvency or liquidation may materially adversely affect our financial condition and results of operations.

25

Our method of accounting for investments in oil and natural gas properties may result in impairment of asset value.

        We account for our oil and natural gas producing activities using the full cost method of accounting. Accordingly, all costs incurred in the acquisition, exploration and development of proved oil and natural gas properties, including the costs of abandoned properties, dry holes, geophysical costs and annual lease rentals are capitalized. We also capitalize direct operating costs for services performed with internally owned drilling and well servicing equipment. All general and administrative corporate costs unrelated to drilling activities are expensed as incurred. Sales or other dispositions of oil and natural gas properties are accounted for as adjustments to capitalized costs, with no gain or loss recorded unless the ratio of cost to proved reserves would significantly change. Depletion of evaluated oil and natural gas properties is computed on the units of production method based on proved reserves. The average depletion rate per BOE of production was $21.03 and $20.32 for 2012 and 2011, respectively. Total depletion expense for oil and natural gas properties was $54.2 million and $19.6 million for 2012 and 2011, respectively.

        The net capitalized costs of proved oil and natural gas properties are subject to a full cost ceiling limitation in which the costs are not allowed to exceed their related estimated future net revenues discounted at 10%. To the extent capitalized costs of evaluated oil and natural gas properties, net of accumulated depreciation, depletion, amortization and impairment exceed the discounted future net revenues of proved reserves, the excess capitalized costs are charged to expense.

        To date, we have not recorded any impairment on proved oil and natural gas properties. However, we may experience ceiling test write downs in the future. Please read "Management's Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies and Estimates—Impairment" for a more detailed description of our method of accounting.

Our estimated reserves are based on many assumptions that may turn out to be inaccurate. Any significant inaccuracies in these reserve estimates or underlying assumptions will materially affect the quantities and present value of our proved reserves.

        Oil and natural gas reserve engineering is not an exact science and requires subjective estimates of underground accumulations of reserves and assumptions concerning future commodity prices, production levels, EURs and operating and development costs. As a result, estimated quantities of proved reserves, projections of future production rates and the timing of development expenditures may be incorrect. Our estimates of proved reserves and related valuations as of December 31, 2012 and 2011 are based on proved reserve reports prepared by CG&A, our independent petroleum engineers. CG&A conducted a well-by-well review of all our properties for the periods covered by its proved reserve reports using information provided by us. Over time, we may make material changes to proved reserve estimates taking into account the results of actual drilling, testing and production. Also, certain assumptions regarding future commodity prices, production levels and operating and development costs may prove incorrect. Any significant variance from these assumptions to actual figures could greatly affect our estimates of proved reserves, the economically recoverable quantities of reserves attributable to any particular group of properties, the classifications of reserves based on risk of recovery and estimates of the future net cash flows. A substantial portion of our reserve estimates are made without the benefit of a lengthy production history, which are less reliable than estimates based on a lengthy production history. Numerous changes over time to the assumptions on which our reserve estimates are based, as described above, often result in the actual quantities of reserves we ultimately recover being different from our estimates.

26

        The estimates of proved reserves as of December 31, 2012 and 2011 included in this prospectus were prepared using an average price equal to the unweighted arithmetic average of hydrocarbon prices received on a field-by-field basis on the first day of each month within the 12 months ended December 31, 2012 and 2011, respectively, in accordance with GAAP. Reserve estimates do not include any value for probable or possible reserves that may exist, nor do they include any value for unproved acreage. The reserve estimates represent our net revenue interest in our properties.

        The timing of both our production and our incurrence of costs in connection with the development and production of reserves will affect the timing of actual future net cash flows from proved reserves.

SEC rules could limit our ability to book additional PUDs in the future.

        SEC rules require that, subject to limited exceptions, PUDs may only be booked if they relate to wells scheduled to be drilled within five years after the date of booking. This requirement has limited and may continue to limit our ability to book additional PUDs as we pursue our drilling program. Moreover, we may be required to write down our PUDs if we do not drill those wells within the required five-year timeframe.

The Standardized Measure of discounted future net cash flows from our proved reserves will not be the same as the current market value of our estimated oil and natural gas reserves.

        You should not assume that the Standardized Measure of discounted future net cash flows from our proved reserves is the current market value of our estimated oil and natural gas reserves. In accordance with SEC requirements in effect at December 31, 2012 and 2011, we based the discounted future net cash flows from our proved reserves on the 12-month first-day-of-the-month oil and natural gas average prices without giving effect to derivative transactions. Actual future net cash flows from our oil and natural gas properties will be affected by factors such as:

•

actual prices we receive for oil and natural gas;

•

actual cost of development and production expenditures;

•

the amount and timing of actual production; and

•

changes in governmental regulations or taxation.

        The timing of both our production and our incurrence of expenses in connection with the development and production of oil and natural gas properties will affect the timing and amount of actual future net revenues from proved reserves, and thus their actual present value. In addition, the 10% discount factor we use when calculating Standardized Measure may not be the most appropriate discount factor based on interest rates in effect from time to time and risks associated with us or the oil and natural gas industry in general. As a limited partnership, our predecessor was not subject to federal taxation. Accordingly, our Standardized Measure does not provide for federal corporate income taxes because taxable income was passed through to its partners. As a corporation, we will be treated as a taxable entity for federal income tax purposes and our future income taxes will be dependent on our future taxable income. Actual future prices and costs may differ materially from those used in the present value estimates included in this prospectus which could have a material effect on the value of our reserves.

All of our properties are located in the Permian Basin, making us vulnerable to risks associated with operating in one geographic area.

        All of our producing properties are located in the Permian Basin. As a result of this concentration, we may be disproportionately exposed to the impact of regional supply and demand factors, delays or interruptions of production from wells in this area caused by governmental regulation, processing or transportation capacity constraints, availability of equipment, facilities, personnel or services market

27

limitations or interruption of the processing or transportation of crude oil, natural gas or NGLs. In addition, the effect of fluctuations on supply and demand may become more pronounced within specific geographic oil and natural gas producing areas such as the Permian Basin, which may cause these conditions to occur with greater frequency or magnify the effects of these conditions. Due to the concentrated nature of our portfolio of oil and natural gas properties, a number of our properties could experience any of the same conditions at the same time, resulting in a relatively greater impact on our results of operations than they might have on other companies that have a more diversified portfolio of properties. Such delays or interruptions could have a material adverse effect on our financial condition and results of operations.

We depend upon a limited number of significant purchasers for the sale of most of our production. The loss of one or more of these purchasers could, among other factors, limit our access to suitable markets for the hydrocarbons we produce.

        The availability of a ready market for any hydrocarbons we produce depends on numerous factors beyond the control of our management, including but not limited to the extent of domestic production and imports of oil, the proximity and capacity of natural gas pipelines, the availability of skilled labor, materials and equipment, the effect of state and federal regulation of oil and natural gas production and federal regulation of natural gas sold in interstate commerce. In addition, we depend upon a limited number of significant purchasers for the sale of most of our production, and our contracts with those customers typically are on a month-to-month basis. The loss of these customers could adversely affect our revenues and have a material adverse effect on our financial condition and results of operations. We cannot assure you that any of our customers will continue to do business with us or that we will continue to have ready access to suitable markets for our future production.

Our operations are substantially dependent on the availability of water. Restrictions on our ability to obtain water may have an adverse effect on our financial condition, results of operations and cash flows.

        Water is an essential component of deep shale oil and natural gas production during both the drilling and hydraulic fracturing processes. Historically, we have been able to purchase water from local land owners for use in our operations. According to the Lower Colorado River Authority, during 2011, Texas experienced the lowest inflows of water of any year in recorded history. As a result of this severe drought, some local water districts have begun restricting the use of water subject to their jurisdiction for hydraulic fracturing to protect local water supply. If we are unable to obtain water to use in our operations from local sources, we may be unable to economically produce our reserves, which could have an adverse effect on our financial condition, results of operations and cash flows.

We may face unanticipated water and other waste disposal costs.

        We may be subject to regulation that restricts our ability to discharge water produced as part of our natural gas production operations. Productive zones frequently contain water that must be removed in order for the natural gas to produce, and our ability to remove and dispose of sufficient quantities of water from the various zones will determine whether we can produce natural gas in commercial quantities. The produced water must be transported from the lease and injected into disposal wells. The availability of disposal wells with sufficient capacity to receive all of the water produced from our wells may affect our ability to produce our wells. Also, the cost to transport and dispose of that water, including the cost of complying with regulations concerning water disposal, may reduce our profitability.

        Where water produced from our projects fails to meet the quality requirements of applicable regulatory agencies, our wells produce water in excess of the applicable volumetric permit limits, the disposal wells fail to meet the requirements of all applicable regulatory agencies, or we are unable to secure access to disposal wells with sufficient capacity to accept all of the produced water, we may have

28

to shut in wells, reduce drilling activities, or upgrade facilities for water handling or treatment. The costs to dispose of this produced water may increase if any of the following occur:

•

we cannot obtain future permits from applicable regulatory agencies;

•

water of lesser quality or requiring additional treatment is produced;

•

our wells produce excess water;

•

new laws and regulations require water to be disposed in a different manner; or

•

costs to transport the produced water to the disposal wells increase.

Declining general economic, business or industry conditions may have a material adverse effect on our results of operations, liquidity and financial condition.

        Concerns over global economic conditions, energy costs, geopolitical issues, inflation, the availability and cost of credit, the European debt crisis and the United States financial market have contributed to increased economic uncertainty and diminished expectations for the global economy. In addition, continued hostilities in the Middle East and the occurrence or threat of terrorist attacks in the United States or other countries could adversely affect the global economy. These factors, combined with volatile commodity prices, declining business and consumer confidence and increased unemployment, have precipitated an economic slowdown and a recession. Concerns about global economic growth have had a significant adverse impact on global financial markets and commodity prices. If the economic climate in the United States or abroad deteriorates, worldwide demand for petroleum products could diminish, which could impact the price at which we can sell our production, affect the ability of our vendors, suppliers and customers to continue operations and ultimately adversely impact our results of operations, liquidity and financial condition.

We have incurred losses from operations during certain periods since our inception and may do so in the future.

        We incurred a net loss of $1.1 million for 2011, our first full year of operation, and we may incur net losses in the future. Our development of and participation in an increasingly larger number of drilling locations has required and will continue to require substantial capital expenditures. The uncertainty and risks described in this prospectus may impede our ability to economically find, develop and acquire reserves. As a result, we may not be able to sustain profitability or positive cash flows provided by operating activities in the future.

Part of our strategy involves drilling in existing or emerging shale plays using the latest available horizontal drilling and completion techniques, which involve risks and uncertainties in their application.

        Our operations involve utilizing the latest drilling and completion techniques as developed by us and our service providers. While horizontal drilling is a significant part of our growth strategy, we have not previously drilled a horizontal well and therefore are subject to increased risks associated with horizontal drilling as compared to companies that have experience in horizontal drilling activities.

        Risks that we face while drilling include, but are not limited to, failing to land our wellbore in the desired drilling zone, not staying in the desired drilling zone while drilling horizontally through the formation, not running our casing the entire length of the wellbore and not being able to run tools and other equipment consistently through the horizontal wellbore. Risks that we face while completing our wells include, but are not limited to, not being able to fracture stimulate the planned number of stages, not being able to run tools the entire length of the wellbore during completion operations and not successfully cleaning out the wellbore after completion of the final fracture stimulation stage. We expect to face many of these similar risks when we commence our horizontal drilling program. In

29

addition, to the extent we engage in horizontal drilling, those activities may adversely affect our ability to successfully drill in one or more of our identified vertical drilling locations.

        Ultimately, the success of these drilling and completion techniques can only be evaluated over time as more wells are drilled and production profiles are established over a sufficiently long time period. If our drilling results are less than anticipated or we are unable to execute our drilling program because of capital constraints, lease expirations, access to gathering systems and/or commodity prices decline, the return on our investment in these areas may not be as attractive as we anticipate. Further, as a result of any of these developments we could incur material write-downs of our oil and natural gas properties and the value of our undeveloped acreage could decline in the future.

Our level of indebtedness may increase and reduce our financial flexibility.

        As of March 31, 2013, on a pro forma basis giving effect to our April 2013 senior notes offering and the application of the net proceeds therefrom, we would have had a total of $503.4 million in outstanding indebtedness and $264.1 million of borrowing capacity under our credit agreement. We may incur significant indebtedness in the future in order to make acquisitions or to develop our properties.

        Our level of indebtedness could affect our operations in several ways, including the following:

•

a significant portion of our cash flows could be used to service our indebtedness;

•

a high level of debt would increase our vulnerability to general adverse economic and industry conditions;

•

the covenants contained in the agreements governing our outstanding indebtedness limit our ability to borrow additional funds, dispose of assets, pay dividends and make certain investments;

•

a high level of debt may place us at a competitive disadvantage compared to our competitors that are less leveraged and therefore, may be able to take advantage of opportunities that our indebtedness would prevent us from pursuing;

•

our debt covenants may also affect our flexibility in planning for, and reacting to, changes in the economy and in our industry;

•

a high level of debt may make it more likely that a reduction in our borrowing base following a periodic redetermination could require us to repay a portion of our then-outstanding bank borrowings; and

•

a high level of debt may impair our ability to obtain additional financing in the future for working capital, capital expenditures, acquisitions, general corporate or other purposes.

        A high level of indebtedness increases the risk that we may default on our debt obligations. Our ability to meet our debt obligations and to reduce our level of indebtedness depends on our future performance. General economic conditions, commodity prices and financial, business and other factors affect our operations and our future performance. Many of these factors are beyond our control. We may not be able to generate sufficient cash flows to pay the interest on our debt and future working capital, borrowings or equity financing may not be available to pay or refinance such debt. Factors that will affect our ability to raise cash through an offering of our capital stock or a refinancing of our debt include financial market conditions, the value of our assets and our performance at the time we need capital.

30

The agreements governing our indebtedness contain restrictive covenants that may limit our ability to respond to changes in market conditions or pursue business opportunities.

        Our credit agreement and the indenture governing our senior notes contain restrictive covenants that limit our ability to, among other things:

•

incur additional indebtedness;

•

create additional liens;

•

sell assets;

•

merge or consolidate with another entity;

•

pay dividends or make other distributions;

•

engage in transactions with affiliates; and

•

enter into certain commodity derivative contracts.

        In addition, our credit agreement requires us to maintain certain financial ratios and tests. The requirement that we comply with these provisions may materially adversely affect our ability to react to changes in market conditions, take advantage of business opportunities we believe to be desirable, obtain future financing, fund needed capital expenditures or withstand a continuing or future downturn in our business.

If we are unable to comply with the restrictions and covenants in the agreements governing our indebtedness, there could be an event of default under the terms of such agreements, which could result in an acceleration of repayment.

        If we are unable to comply with the restrictions and covenants in our credit agreement or the indenture governing our senior notes, there could be an event of default. Our ability to comply with these restrictions and covenants, including meeting the financial ratios and tests under our credit agreement, may be affected by events beyond our control. As a result, we cannot assure that we will be able to comply with these restrictions and covenants or meet such financial ratios and tests. In the event of a default under our credit agreement or the indenture governing our senior notes, the lenders could terminate their commitments to lend or accelerate the loans and declare all amounts borrowed due and payable. If any of these events occur, our assets might not be sufficient to repay in full all of our outstanding indebtedness and we may be unable to find alternative financing. Even if we could obtain alternative financing, it might not be on terms that are favorable or acceptable to us. Additionally, we may not be able to amend our credit agreement or obtain needed waivers on satisfactory terms.

Our borrowings under our credit agreement expose us to interest rate risk.

        Our results of operations are exposed to interest rate risk associated with borrowings under our credit agreement, which bear interest at a rate elected by us that is based on the prime, LIBOR or federal funds rate plus margins ranging from 0.50% to 2.50% depending on the type of loan used and the amount of the loan outstanding in relation to the borrowing base. As of March 31, 2013, the weighted-average interest rate on outstanding borrowings under our credit agreement was approximately 2.5%. If interest rates increase, so will our interest costs, which may have a material adverse effect on our results of operations and financial condition.

31

Any significant reduction in our borrowing base under our credit agreement as a result of the periodic borrowing base redeterminations or otherwise may negatively impact our ability to fund our operations.

        Under our credit agreement, which currently provides for a $320 million borrowing base, we are subject to collateral borrowing base redeterminations based on our proved reserves. Any significant reduction in our borrowing base as a result of such borrowing base redeterminations or otherwise may negatively impact our liquidity and our ability to fund our operations and, as a result, may have a material adverse effect on our financial condition, results of operations and cash flows.

We rely on a few key employees whose absence or loss could adversely affect our business.

        Many key responsibilities within our business have been assigned to a small number of employees. The loss of their services could adversely affect our business. In particular, the loss of the services of one or more members of our management team, including our Chief Executive Officer, Robert C. Reeves, could disrupt our operations. We have employment agreements with these executives which contain restrictions on competition with us in the event they cease to be employed by us. However, as a practical matter, such employment agreements may not assure the retention of our employees. Further, we do not maintain "key person" life insurance policies on any of our employees. As a result, we are not insured against any losses resulting from the death of our key employees.

Operating hazards and uninsured risks may result in substantial losses and could prevent us from realizing profits.

        Our operations are subject to all of the hazards and operating risks associated with drilling for and production of oil and natural gas, including the risk of fire, explosions, blowouts, surface cratering, uncontrollable flows of natural gas, oil and formation water, pipe or pipeline failures, abnormally pressured formations, casing collapses and environmental hazards such as oil spills, natural gas leaks, ruptures or discharges of toxic gases. In addition, our operations are subject to risks associated with hydraulic fracturing, including any mishandling, surface spillage or potential underground migration of fracturing fluids, including chemical additives. The occurrence of any of these events could result in substantial losses to us due to injury or loss of life, severe damage to or destruction of property, natural resources and equipment, pollution or other environmental damage, clean-up responsibilities, regulatory investigation and penalties, suspension of operations and repairs to resume operations.

        We endeavor to contractually allocate potential liabilities and risks between us and the parties that provide us with services and goods, which include pressure pumping and hydraulic fracturing, drilling and cementing services and tubular goods for surface, intermediate and production casing. Under our agreements with our vendors, to the extent responsibility for environmental liability is allocated between the parties, (1) our vendors generally assume all responsibility for control and removal of pollution or contamination which originates above the surface of the land and is directly associated with such vendors' equipment while in their control and (2) we generally assume the responsibility for control and removal of all other pollution or contamination which may occur during our operations, including pre-existing pollution and pollution which may result from fire, blowout, cratering, seepage or any other uncontrolled flow of oil, natural gas or other substances, as well as the use or disposition of all drilling fluids. In addition, we generally agree to indemnify our vendors for loss or destruction of vendor-owned property that occurs in the well hole or as a result of the use of equipment, certain corrosive fluids, additives, chemicals or proppants. However, despite this general allocation of risk, we might not succeed in enforcing such contractual allocation, might incur an unforeseen liability falling outside the scope of such allocation or may be required to enter into contractual arrangements with terms that vary from the above allocations of risk. As a result, we may incur substantial losses which could materially and adversely affect our financial condition and results of operations.

32

        In accordance with what we believe to be customary industry practice, we maintain insurance against some, but not all, of our business risks. Our insurance may not be adequate to cover any losses or liabilities we may suffer. Also, insurance may no longer be available to us or, if it is, its availability may be at premium levels that do not justify its purchase. The occurrence of a significant uninsured claim, a claim in excess of the insurance coverage limits maintained by us or a claim at a time when we are not able to obtain liability insurance could have a material adverse effect on our ability to conduct normal business operations and on our financial condition, results of operations or cash flows. In addition, we may not be able to secure additional insurance or bonding that might be required by new governmental regulations. This may cause us to restrict our operations, which might severely impact our financial condition. We may also be liable for environmental damage caused by previous owners of properties purchased by us, which liabilities may not be covered by insurance.

        Since hydraulic fracturing activities are part of our operations, they are covered by our insurance against claims made for bodily injury, property damage and clean-up costs stemming from a sudden and accidental pollution event. However, we may not have coverage if we are unaware of the pollution event and unable to report the "occurrence" to our insurance company within the time frame required under our insurance policy. We have no coverage for gradual, long-term pollution events. In addition, these policies do not provide coverage for all liabilities, and we cannot assure you that the insurance coverage will be adequate to cover claims that may arise, or that we will be able to maintain adequate insurance at rates we consider reasonable. A loss not fully covered by insurance could have a material adverse effect on our financial condition, results of operations and cash flows. Please read "Business—Operational Hazards and Insurance" for a description of our insurance coverage.

Our failure to successfully identify, complete and integrate future acquisitions of properties or businesses could reduce our operating results and slow our growth.

        There is intense competition for acquisition opportunities in our industry and we may not be able to identify attractive acquisition opportunities. Even if we do identify attractive acquisition opportunities, we may not be able to complete the acquisition or do so on commercially acceptable terms. Competition for acquisitions may increase the cost of, or cause us to refrain from, completing acquisitions. Our ability to complete acquisitions is dependent upon, among other things, our ability to obtain debt and equity financing and, in some cases, regulatory approvals. Further, these acquisitions may be in geographic regions in which we do not currently operate, which could result in unforeseen operating difficulties and difficulties in coordinating geographically dispersed operations, personnel and facilities. In addition, if we enter into new geographic markets, we may be subject to additional and unfamiliar legal and regulatory requirements. Compliance with these regulatory requirements may impose substantial additional obligations on us and our management, cause us to expend additional time and resources in compliance activities and increase our exposure to penalties or fines for non-compliance with such additional legal requirements. Completed acquisitions could require us to invest further in operational, financial and management information systems and to attract, retain, motivate and effectively manage additional employees. The inability to effectively manage the integration of acquisitions could reduce our focus on subsequent acquisitions and current operations, which, in turn, could negatively impact our results of operations and growth. Our financial condition and results of operations may fluctuate significantly from period to period, based on whether or not significant acquisitions are completed in particular periods.

        Any acquisition involves potential risks, including, among other things:

•

the validity of our assumptions about estimated proved reserves, future production, commodity prices, revenues, capital expenditures, operating expenses and costs;

•

an inability to obtain satisfactory title to the assets we acquire;

33

•

a decrease in our liquidity by using a significant portion of our available cash or borrowing capacity to finance acquisitions;

•

a significant increase in our interest expense or financial leverage if we incur additional debt to finance acquisitions;

•

the assumption of unknown liabilities, losses or costs for which we obtain no or limited indemnity or other recourse;

•

the diversion of management's attention from other business concerns;

•

an inability to hire, train or retain qualified personnel to manage and operate our growing assets; and

•

the occurrence of other significant changes, such as impairment of oil and natural gas properties, goodwill or other intangible assets, asset devaluation or restructuring charges.

Properties we acquire may not produce as projected, and we may be unable to determine reserve potential, identify liabilities associated with the properties that we acquire or obtain protection from sellers against such liabilities.

        Acquiring oil and natural gas properties requires us to assess reservoir and infrastructure characteristics, including recoverable reserves, development and operating costs and potential environmental and other liabilities. Such assessments are inexact and inherently uncertain. In connection with the assessments, we perform a review of the subject properties, but such a review will not reveal all existing or potential problems. In the course of our due diligence, we may not inspect every well or pipeline. We cannot necessarily observe structural and environmental problems, such as pipe corrosion, when an inspection is made. We may not be able to obtain contractual indemnities from the seller for liabilities created prior to our purchase of the property. We may be required to assume the risk of the physical condition of the properties in addition to the risk that the properties may not perform in accordance with our expectations.

We may incur losses as a result of title defects in the properties in which we invest.

        It is our practice in acquiring oil and natural gas leases or interests not to incur the expense of retaining lawyers to examine the title to the mineral interest. Rather, we rely upon the judgment of oil and natural gas lease brokers or landmen who perform the fieldwork in examining records in the appropriate governmental office before attempting to acquire a lease in a specific mineral interest.

        Prior to the drilling of an oil or natural gas well, however, it is the normal practice in our industry for the person or company acting as the operator of the well to obtain a preliminary title review to ensure there are no obvious defects in title to the well. Frequently, as a result of such examinations, certain curative work must be done to correct defects in the marketability of the title, and such curative work entails expense. Our failure to cure any title defects may delay or prevent us from utilizing the associated mineral interest, which may adversely impact our ability in the future to increase production and reserves. Additionally, undeveloped acreage has greater risk of title defects than developed acreage. If there are any title defects or defects in assignment of leasehold rights in properties in which we hold an interest, we will suffer a financial loss.

Competition in the oil and natural gas industry is intense, which may adversely affect our ability to succeed.

        The oil and natural gas industry is intensely competitive, and we compete with other companies that have greater resources than us. Many of these companies not only explore for and produce oil and natural gas, but also carry on midstream and refining operations and market petroleum and other products on a regional, national or worldwide basis. These companies may be able to pay more for productive oil and natural gas properties and exploratory prospects or define, evaluate, bid for and purchase a greater number of properties and prospects than our financial or human resources permit. In addition, these companies may have a greater ability to continue exploration activities during periods of low oil and natural gas market prices. Our larger competitors may be able to absorb the burden of

34

present and future federal, state, local and other laws and regulations more easily than we can, which would adversely affect our competitive position. Our ability to acquire additional properties and to discover reserves in the future will be dependent upon our ability to evaluate and select suitable properties and to consummate transactions in a highly competitive environment. In addition, because we have fewer financial and human resources than many companies in our industry, we may be at a disadvantage in bidding for exploratory prospects and producing reserves.

        The oil and natural gas industry is characterized by rapid and significant technological advancements and introductions of new products and services using new technologies. As others use or develop new technologies, we may be placed at a competitive disadvantage or competitive pressures may force us to implement those new technologies at substantial costs. In addition, other oil and natural gas companies may have greater financial, technical and personnel resources that allow them to enjoy technological advantages and may in the future allow them to implement new technologies before we can. We may not be able to respond to these competitive pressures and implement new technologies on a timely basis or at an acceptable cost. If one or more of the technologies we use now or in the future were to become obsolete or if we are unable to use the most advanced commercially available technology, our business, financial condition and results of operations could be materially adversely affected.

Our use of 2-D and 3-D seismic data is subject to interpretation and may not accurately identify the presence of oil and natural gas, which could adversely affect the results of our drilling operations.

        Even when properly used and interpreted, 2-D and 3-D seismic data and visualization techniques are only tools used to assist geoscientists in identifying subsurface structures and hydrocarbon indicators and do not enable the interpreter to know whether hydrocarbons are, in fact, present in those structures. In addition, the use of 3-D seismic and other advanced technologies requires greater predrilling expenditures than traditional drilling strategies, and we could incur losses as a result of such expenditures. As a result, our drilling activities may not be successful or economical.

Conservation measures and technological advances could reduce demand for oil and natural gas.

        Fuel conservation measures, alternative fuel requirements, increasing consumer demand for alternatives to oil and natural gas, technological advances in fuel economy and energy generation devices could reduce demand for oil and natural gas. The impact of the changing demand for oil and natural gas services and products may have a material adverse effect on our business, financial condition, results of operations and cash flows.

The marketability of our production is dependent upon transportation and other facilities, certain of which we do not control. When these facilities are unavailable, our operations can be interrupted and our revenues reduced.

        The marketability of our production depends in part upon the availability, proximity and capacity of transportation facilities owned by third parties. Our oil production is transported from the wellhead to our tank batteries by our gathering system. Our purchasers then transport the oil by truck to a pipeline for transportation. Our natural gas production is generally transported by our gathering lines from the wellhead to an interconnection point with the purchaser. We do not control these trucks and other third-party transportation facilities and our access to them may be limited or denied. Insufficient production from our wells to support the construction of pipeline facilities by our purchasers or a significant disruption in the availability of our or third-party transportation facilities or other production facilities could adversely impact our ability to deliver to market or produce our production and thereby cause a significant interruption in our operations.

        In the past we have been required to flare a portion of our natural gas production for a number of reasons, including the fact that (1) our well is not yet tied into the third-party gathering system, (2) the pressures on the third-party gathering system are too high to allow additional production from our well to be transported or (3) our production is prorated due to high demand on the third-party gathering system. During the first quarter of 2013, we flared an average of approximately 2.0 MMcf/D, or

35

331 BOE/D, of natural gas, which included both residue gas and NGL production. We expect to continue flaring approximately 3.0 MMcf/D to 4.0 MMcf/D until further improvements can be made to certain gathering systems near our wells. These improvements are scheduled to come on line in mid-2013, although we cannot guarantee that this will be the case.

        Also, the transfer of our oil, natural gas and NGLs on third-party pipelines may be curtailed or delayed if it does not meet the quality specifications of the pipeline owners. Our access to transportation options, including trucks owned by third parties, can also be affected by U.S. federal and state regulation of oil and natural gas production and transportation, general economic conditions and changes in supply and demand. If, in the future, we are unable, for any sustained period, to implement acceptable delivery or transportation arrangements or encounter production-related difficulties, we may be required to shut in or curtail production. Any such shut in or curtailment, or an inability to obtain favorable terms for delivery of our production, would adversely affect our financial condition and results of operations.

Our operations are subject to various governmental regulations which require compliance that can be burdensome and expensive.

        Our operations are subject to various federal, state and local governmental regulations that may be changed from time to time in response to economic and political conditions. Matters subject to regulation include discharge permits for drilling operations, drilling bonds, reports concerning operations, the spacing of wells, unitization and pooling of properties and taxation. From time to time, regulatory agencies have imposed price controls and limitations on production by restricting the rate of flow of oil and natural gas wells below actual production capacity to conserve supplies of oil and natural gas. In addition, the production, handling, storage, transportation, remediation, emission and disposal of oil and natural gas, by-products thereof and other substances and materials produced or used in connection with oil and natural gas operations are subject to regulation under federal, state and local laws and regulations, primarily relating to protection of human health and the environment. Failure to comply with these laws and regulations may result in the assessment of sanctions, including administrative, civil or criminal penalties, permit revocations, requirements for additional pollution controls and injunctions limiting or prohibiting some or all of our operations. Moreover, these laws and regulations have continually imposed increasingly strict requirements for water and air pollution control and solid waste management. Significant expenditures may be required to comply with governmental laws and regulations applicable to us. We believe the trend of more expansive and stricter environmental legislation and regulations will continue for the foreseeable future. Please read "Business—Regulation" for a description of the laws and regulations that affect us.

Federal and state legislative and regulatory initiatives relating to hydraulic fracturing could result in increased costs and additional operating restrictions or delays.

        Hydraulic fracturing is an important common practice that is used to stimulate production of hydrocarbons, particularly natural gas, from tight formations, including shales. The process involves the injection of water, sand and chemicals under pressure into formations to fracture the surrounding rock and stimulate production. The federal Safe Drinking Water Act (the "SDWA") regulates the underground injection of substances through the Underground Injection Control ("UIC") program. Hydraulic fracturing is generally exempt from regulation under the UIC program, and the hydraulic fracturing process is typically regulated by state oil and natural gas commissions. The Environmental Protection Agency (the "EPA") however, has recently taken the position that hydraulic fracturing with fluids containing diesel fuel is subject to regulation under the UIC program, specifically as "Class II" UIC wells. At the same time, the EPA has commenced a study of the potential environmental impacts of hydraulic fracturing activities, and a committee of the U.S. House of Representatives is also conducting an investigation of hydraulic fracturing practices. Moreover, the EPA commenced a study regarding the environmental effects of hydraulic fracturing activities. The EPA issued a Progress Report in December 2012 and a final draft is anticipated by 2014 for peer review and public comment. As part of these studies, both the EPA and the House committee have requested that certain companies

36

provide them with information concerning the chemicals used in the hydraulic fracturing process. These studies, depending on their results, could spur initiatives to regulate hydraulic fracturing under the SDWA or otherwise. Legislation to amend the SDWA to repeal the exemption for hydraulic fracturing from the definition of "underground injection" and require federal permitting and regulatory control of hydraulic fracturing, as well as legislative proposals to require disclosure of the chemical constituents of the fluids used in the fracturing process, were proposed in recent sessions of Congress. The U.S. Congress continues to consider legislation to amend the SDWA.

        Federal agencies are also considering additional regulation of hydraulic fracturing. On October 20, 2011, the EPA announced its intention to propose federal Clean Water Act regulations by 2014 governing wastewater discharges from hydraulic fracturing and certain other natural gas operations.

        On August 16, 2012, the EPA published final regulations under the federal Clean Air Act, as amended, (the "CAA") that establish new air emission controls for oil and natural gas production and natural gas processing operations. Specifically, the EPA's rule package includes New Source Performance Standards to address emissions of sulfur dioxide and volatile organic compounds ("VOCs") and a separate set of emission standards to address hazardous air pollutants frequently associated with oil and natural gas production and processing activities. The final rule includes a 95% reduction in VOCs emitted by requiring the use of reduced emission completions or "green completions" on all hydraulically-fractured wells constructed or refractured after January 1, 2015. The rules also establish specific new requirements regarding emissions from compressors, controllers, dehydrators, storage tanks and other production equipment. The EPA received numerous requests for reconsideration of these rules from both industry and the environmental community, and court challenges to the rules were also filed. The EPA intends to issue revised rules in 2013 that are likely responsive to some of these requests. For example, on April 12, 2013, the EPA published a proposed amendment extending compliance dates for certain storage vessels. The final revised rules could require modifications to our operations or increase our capital and operating costs without being offset by increased product capture. At this point, we cannot predict the final regulatory requirements or the cost to comply with such requirements with any certainty. The U.S. Department of the Interior has also announced its intention to propose a new rule regulating hydraulic fracturing activities on federal lands, including requirements for disclosure, wellbore integrity and handling of flowback water.

        Several states, including Texas have adopted or are considering adopting regulations that could restrict or prohibit hydraulic fracturing in certain circumstances and/or require the disclosure of the composition of hydraulic fracturing fluids. The Texas Railroad Commission recently adopted rules and regulations requiring that the well operator disclose the list of chemical ingredients subject to the requirements of the federal Occupational Safety and Health Act ("OSHA") for disclosure on an internet website and also file the list of chemicals with the Texas Railroad Commission with the well completion report. The total volume of water used to hydraulically fracture a well must also be disclosed to the public and filed with the Texas Railroad Commission. We plan to use hydraulic fracturing extensively in connection with the development and production of certain of our oil and natural gas properties and any increased federal, state, local, foreign or international regulation of hydraulic fracturing could reduce the volume of reserves that we can economically recover, which could materially and adversely affect our revenues and results of operations.

        There has been increasing public controversy regarding hydraulic fracturing with regard to use of fracturing fluids, impacts on drinking water supplies, use of waters and the potential for impacts to surface water, groundwater and the environment generally. A number of lawsuits and enforcement actions have been initiated across the country implicating hydraulic fracturing practices. If new laws or regulations that significantly restrict hydraulic fracturing are adopted, such laws could make it more difficult or costly for us to perform fracturing to stimulate production from tight formations as well as make it easier for third parties opposing the hydraulic fracturing process to initiate legal proceedings based on allegations that specific chemicals used in the fracturing process could adversely affect groundwater. In addition, if hydraulic fracturing is further regulated at the federal or state level, our fracturing activities could become subject to additional permitting and financial assurance requirements,

37

more stringent construction specifications, increased monitoring, reporting and recordkeeping obligations, plugging and abandonment requirements and also to attendant permitting delays and potential increases in costs. Such legislative changes could cause us to incur substantial compliance costs, and compliance or the consequences of any failure to comply by us could have a material adverse effect on our financial condition and results of operations. At this time, it is not possible to estimate the impact on our business of newly enacted or potential federal or state legislation governing hydraulic fracturing.

Our operations may be exposed to significant delays, costs and liabilities as a result of environmental, health and safety requirements applicable to our business activities.

        We may incur significant delays, costs and liabilities as a result of federal, state and local environmental, health and safety requirements applicable to our exploration, development and production activities. These laws and regulations may require us to obtain a variety of permits or other authorizations governing our air emissions, water discharges, waste disposal or other environmental impacts associated with drilling, producing and other operations; regulate the sourcing and disposal of water used in the drilling, fracturing and completion processes; limit or prohibit drilling activities in certain areas and on certain lands lying within wilderness, wetlands, frontier and other protected areas; require remedial action to prevent or mitigate pollution from former operations such as plugging abandoned wells or closing earthen pits; and/or impose substantial liabilities for spills, pollution or failure to comply with regulatory filings. In addition, these laws and regulations may restrict the rate of oil or natural gas production. These laws and regulations are complex, change frequently and have tended to become increasingly stringent over time. Failure to comply with these laws and regulations may result in the assessment of administrative, civil and criminal penalties, imposition of cleanup and site restoration costs and liens, the suspension or revocation of necessary permits, licenses and authorizations, the requirement that additional pollution controls be installed and, in some instances, issuance of orders or injunctions limiting or requiring discontinuation of certain operations.

        Under certain environmental laws that impose strict as well as joint and several liability, we may be required to remediate contaminated properties currently or formerly operated by us or facilities of third parties that received waste generated by our operations regardless of whether such contamination resulted from the conduct of others or from consequences of our own actions that were in compliance with all applicable laws at the time those actions were taken. In addition, claims for damages to persons or property, including natural resources, may result from the environmental, health and safety impacts of our operations. In addition, the risk of accidental spills or releases from our operations could expose us to significant liabilities under environmental laws. Moreover, public interest in the protection of the environment has increased dramatically in recent years. The trend of more expansive and stringent environmental legislation and regulations applied to the oil and natural gas industry could continue, resulting in increased costs of doing business and consequently affecting profitability. To the extent laws are enacted or other governmental action is taken that restricts drilling or imposes more stringent and costly operating, waste handling, disposal and cleanup requirements, our business, prospects, financial condition or results of operations could be materially adversely affected.

Restrictions on drilling activities intended to protect certain species of wildlife may adversely affect our ability to conduct drilling activities in some of the areas where we operate.

        Oil and natural gas operations in our operating areas can be adversely affected by seasonal or permanent restrictions on drilling activities designed to protect various wildlife. Seasonal restrictions may limit our ability to operate in protected areas and can intensify competition for drilling rigs, oilfield equipment, services, supplies and qualified personnel, which may lead to periodic shortages when drilling is allowed. These constraints and the resulting shortages or high costs could delay our operations and materially increase our operating and capital costs. Permanent restrictions imposed to protect endangered species could prohibit drilling in certain areas or require the implementation of expensive mitigation measures. The designation of previously unprotected species in areas where we operate as threatened or endangered could cause us to incur increased costs arising from species

38

protection measures or could result in limitations on our exploration, development and production activities that could have an adverse impact on our ability to develop and produce our reserves.

The adoption of derivatives legislation by the U.S. Congress could have an adverse effect on our ability to use derivative instruments to reduce the effect of commodity price, interest rate and other risks associated with our business.

        The adoption of derivatives legislation by the U.S. Congress could have an adverse effect on our ability to use derivative instruments to reduce the effect of commodity price, interest rate and other risks associated with our business. The U.S. Congress adopted the Dodd-Frank Wall Street Reform and Consumer Protection Act (HR 4173), which, among other provisions, establishes federal oversight and regulation of the over-the-counter derivatives market and entities that participate in that market. The legislation was signed into law by the President on July 21, 2010, and required the Commodities Futures Trading Commission ("CFTC") and the SEC to promulgate rules and regulations implementing the legislation within 360 days from the date of enactment. In its rulemaking under the legislation, the CFTC proposed regulations to set position limits for certain futures and option contracts in the major energy markets and for swaps that are their economic equivalents. Certain bona fide hedging transactions or positions would be exempt from these position limits. Although the CFTC has promulgated numerous final rules based on its proposals, it is not possible at this time to predict when the CFTC will finalize its proposed regulations or the effect of such regulations on our business. The financial reform legislation may also require us to comply with margin requirements and with certain clearing and trade-execution requirements in connection with our existing or future derivative activities, although the application of those provisions to us is uncertain at this time. The financial reform legislation may also require the counterparties to our derivative instruments to spin off some of their derivatives activities to separate entities, which may not be as creditworthy as the current counterparties. This legislation and any new regulations could significantly increase the cost of derivative contracts (including through requirements to post collateral which could adversely affect our available liquidity), materially alter the terms of derivative contracts, reduce the availability of derivatives to protect against risks we encounter, reduce our ability to monetize or restructure our derivative contracts in existence at that time and increase our exposure to less creditworthy counterparties. If we reduce or change the way we use derivative instruments as a result of the legislation and regulations, our results of operations may become more volatile and our cash flows may be less predictable, which could adversely affect our ability to plan for and fund capital expenditures. Finally, the legislation was intended, in part, to reduce the volatility of oil and natural gas prices, which some legislators attributed to speculative trading in derivatives and commodity instruments related to oil and natural gas. Our revenues could therefore be adversely affected if a consequence of the legislation and regulations is to lower commodity prices. Any of these consequences could have a material adverse effect on our consolidated financial condition, results of operations or cash flows.

Proposed changes to U.S. tax laws, if adopted, could have an adverse effect on our business, financial condition, results of operations and cash flows.

        The U.S. President's Fiscal Year 2014 Budget Proposal includes provisions that would, if enacted, make significant changes to U.S. tax laws. These changes include, but are not limited to, eliminating the immediate deduction for intangible drilling and development costs, eliminating the deduction from income for domestic production activities relating to oil and natural gas exploration and development, repealing the percentage depletion allowance for oil and natural gas properties and extending the amortization period for certain geological and geophysical expenditures. These proposed changes in the U.S. tax laws, if adopted, or other similar changes that reduce or eliminate deductions currently available with respect to oil and natural gas exploration and development, could adversely affect our business, financial condition, results of operations and cash flows.

39

The adoption of climate change legislation by Congress could result in increased operating costs and reduced demand for the oil and natural gas we produce.

        Many nations have agreed to limit emissions of "greenhouse gases" ("GHGs") pursuant to the United Nations Framework Convention on Climate Change, also known as the "Kyoto Protocol." Methane, a primary component of natural gas, and carbon dioxide, a byproduct of the burning of oil, natural gas, and refined petroleum products, are GHGs regulated by the Kyoto Protocol. Although the United States is not participating in the Kyoto Protocol at this time, several states or geographic regions have adopted legislation and regulations to reduce emissions of GHGs. The EPA has adopted two sets of related rules, one of which purports to regulate emissions of GHGs from motor vehicles and the other of which regulates emissions of GHGs from certain large stationary sources of emissions such as power plants or industrial facilities. The EPA finalized the motor vehicle rule in April 2010 and it became effective in January 2011. The EPA adopted the stationary source rule, also known as the "Tailoring Rule," in May 2010, and it also became effective in January 2011. Additionally, in September 2009, the EPA issued a final rule requiring the reporting of GHG emissions from specified large GHG emission sources in the U.S., including NGLs fractionators and local natural gas/distribution companies, beginning in 2011 for emissions occurring in 2010. In November 2010, the EPA expanded its existing GHG reporting rule to include onshore and offshore oil and natural gas production and onshore processing, transmission, storage and distribution facilities, which may include certain of our facilities, beginning in 2012 for emissions occurring in 2011. In addition, the EPA has continued to adopt GHG regulations of other industries, such as the March 2012 proposed GHG rule restricting future development of coal-fired power plants. As a result of this continued regulatory focus, future GHG regulations of the oil and natural gas industry remain a possibility.

        In addition, the U.S. Congress has from time to time considered adopting legislation to reduce emissions of GHGs and almost one-half of the states have already taken legal measures to reduce emissions of GHGs primarily through the planned development of GHG emission inventories and/or regional GHG cap and trade programs. Although the U.S. Congress has not adopted such legislation at this time, it may do so in the future and many states continue to pursue regulations to reduce GHG emissions. Most of these cap and trade programs work by requiring major sources of emissions, such as electric power plants, or major producers of fuels, such as refineries and natural gas processing plants, to acquire and surrender emission allowances corresponding with their annual emissions of GHGs. The number of allowances available for purchase is reduced each year until the overall GHG emission reduction goal is achieved. As the number of GHG emission allowances declines each year, the cost or value of allowances is expected to escalate significantly.

        Restrictions on GHG emissions that may be imposed in various states could adversely affect the oil and natural gas industry. While we are subject to certain federal GHG monitoring and reporting requirements, our operations are not adversely impacted by existing federal, state and local climate change initiatives and, at this time, it is not possible to accurately estimate how future laws or regulations addressing GHG emissions would impact our business.

        In addition, there has been public discussion that climate change may be associated with extreme weather conditions such as more intense hurricanes, thunderstorms, tornados and snow or ice storms, as well as rising sea levels. Another possible consequence of climate change is increased volatility in seasonal temperatures. Some studies indicate that climate change could cause some areas to experience temperatures substantially colder than their historical averages. Extreme weather conditions can interfere with our production and increase our costs and damage resulting from extreme weather may not be fully insured. However, at this time, we are unable to determine the extent to which climate change may lead to increased storm or weather hazards affecting our operations.

40

We will be subject to certain requirements of Section 404 of the Sarbanes-Oxley Act. If we are unable to timely comply with Section 404 or if the costs related to compliance are significant, our profitability, stock price, results of operations and financial condition could be materially adversely affected.

        We will be required to comply with certain provisions of Section 404 of the Sarbanes-Oxley Act as early as December 31, 2013. Section 404 requires that we document and test our internal control over financial reporting and issue management's assessment of our internal control over financial reporting. This section also requires that our independent registered public accounting firm opine on those internal controls upon becoming a large accelerated filer, as defined in the SEC rules, or otherwise ceasing to qualify as an emerging growth company under the JOBS Act. We are evaluating our existing controls against the standards adopted by the Committee of Sponsoring Organizations of the Treadway Commission. During the course of our ongoing evaluation and integration of the internal control over financial reporting, we may identify areas requiring improvement, and we may have to design enhanced processes and controls to address issues identified through this review. For example, we anticipate the need to hire additional administrative and accounting personnel to conduct our financial reporting.

        We believe that the out-of-pocket costs, diversion of management's attention from running the day-to-day operations and operational changes caused by the need to comply with the requirements of Section 404 of the Sarbanes-Oxley Act could be significant. If the time and costs associated with such compliance exceed our current expectations, our results of operations could be adversely affected.

        We cannot be certain at this time that we will be able to successfully complete the procedures, certification and attestation requirements of Section 404 or that we or our independent registered public accounting firm will not identify material weaknesses in our internal control over financial reporting. If we fail to comply with the requirements of Section 404 or if we or our independent registered public accounting firm identify and report such material weaknesses, the accuracy and timeliness of the filing of our annual and quarterly reports may be materially adversely affected and could cause investors to lose confidence in our reported financial information, which could have a negative effect on the stock price of our common stock. In addition, a material weakness in the effectiveness of our internal control over financial reporting could result in an increased chance of fraud and the loss of customers, reduce our ability to obtain financing and require additional expenditures to comply with these requirements, each of which could have a material adverse effect on our business, results of operations and financial condition.

Loss of our information and computer systems could adversely affect our business.

        We are heavily dependent on our information systems and computer based programs, including our well operations information, seismic data, electronic data processing and accounting data. If any of such programs or systems were to fail or create erroneous information in our hardware or software network infrastructure, possible consequences include our loss of communication links, inability to find, produce, process and sell oil and natural gas and inability to automatically process commercial transactions or engage in similar automated or computerized business activities. Any such consequence could have a material adverse effect on our business.

A terrorist attack or armed conflict could harm our business.

        Terrorist activities, anti-terrorist efforts and other armed conflicts involving the United States or other countries may adversely affect the United States and global economies and could prevent us from meeting our financial and other obligations. If any of these events occur, the resulting political instability and societal disruption could reduce overall demand for oil and natural gas, potentially putting downward pressure on demand for our services and causing a reduction in our revenues. Oil and natural gas related facilities could be direct targets of terrorist attacks, and our operations could be adversely impacted if infrastructure integral to our customers' operations is destroyed or damaged. Costs for insurance and other security may increase as a result of these threats, and some insurance coverage may become more difficult to obtain, if available at all.

41

Risks Related to this Offering and Our Common Stock

Athlon Energy Inc.'s only material asset is its interest in Athlon Holdings LP, and Athlon Energy Inc. is accordingly dependent upon distributions from Athlon Holdings LP to pay taxes, make payments under the tax receivable agreement and pay dividends.

        Athlon Energy Inc. is a holding company and has no material assets other than its ownership of New Holdings Units in Athlon Holdings LP. Athlon Energy Inc. has no independent means of generating revenue. Athlon Energy Inc. intends to cause Athlon Holdings LP to make distributions to its unitholders, which include Athlon Energy Inc., members of our management team and certain employees, in an amount sufficient to cover all applicable taxes at assumed tax rates, payments under the tax receivable agreement and dividends, if any, declared by it. To the extent that Athlon Energy Inc. needs funds, and Athlon Holdings LP is restricted from making such distributions under applicable law or regulation or under the terms of its financing arrangements, or is otherwise unable to provide such funds, it could materially adversely affect our liquidity and financial condition.

        Athlon Holdings LP entered into an amended and restated credit agreement dated as of March 19, 2013, which we refer to as our credit agreement. In addition, Athlon Holdings LP entered into an indenture dated as of April 17, 2013 governing its 7³/8% senior notes due 2021. Each of these agreements includes a restricted payment covenant, which places certain restrictions on the ability of Athlon Holdings LP to make distributions to its unitholders, including Athlon Energy Inc.

Our largest stockholder controls a significant percentage of our common stock, and their interests may conflict with those of our other stockholders.

        Upon completion of this offering, assuming the Apollo Funds or their affiliates make no additional purchases of our common stock and based on an estimated valuation of Athlon using an assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus), the Apollo Funds will beneficially own in the aggregate approximately          % of the combined voting power of our common stock (or approximately          % if the underwriters option to purchase additional shares of common stock from the Apollo Funds is exercised in full). As a result, the Apollo Funds will be able to control matters requiring stockholder approval, including the election of directors, changes to our organizational documents and significant corporate transactions. This concentration of ownership makes it unlikely that any other holder or group of holders of our common stock will be able to affect the way we are managed or the direction of our business. In addition, the stockholders agreement that we will enter into in connection with this offering will provide that, except as otherwise required by applicable law, if the Apollo Funds hold: (a) at least 50% of our outstanding common stock, they will have the right to designate no fewer than that number of directors that would constitute a majority of our Board of Directors; (b) at least 30% but less than 50% of our outstanding common stock, they will have the right to designate up to three director nominees; (c) at least 20% but less than 30% of our outstanding common stock, they will have the right to designate up to two director nominees; and (d) at least 10% but less than 20% of our outstanding common stock, they will have the right to designate up to one director nominee. The agreement also provides that if the size of our Board of Directors is increased or decreased at any time to other than seven directors, Apollo's nomination rights will be proportionately increased or decreased, respectively, rounded up to the nearest whole number. In addition, the agreement provides that if the Apollo Funds hold at least 30% of our outstanding common stock, we will cause any committee of our Board of Directors to include in its membership at least one of the Apollo Funds nominees, except to the extent that such membership would violate applicable securities laws or stock exchange or stock market rules. The interests of the Apollo Funds with respect to matters potentially or actually involving or affecting us, such as future acquisitions, financings and other corporate opportunities and attempts to acquire us, may conflict with the interests of our other stockholders. Given this concentrated ownership, the Apollo Funds would have to approve any potential acquisition of us. In addition, certain of our directors are currently employees of Apollo. These directors' duties as employees of Apollo may conflict with their duties as our directors, and the resolution of these conflicts may not always be in our or your best interest.

42

We expect to be a "controlled company" within the meaning of the NYSE rules and, as a result, will qualify for, and intend to rely on, exemptions from certain corporate governance requirements.

        Upon the closing of this offering, the Apollo Funds will continue to control a majority of our voting common stock. As a result, we expect to qualify as a "controlled company" within the meaning of the NYSE corporate governance standards. Under the NYSE rules, a company of which more than 50% of the voting power for the election of directors is held by an individual, group or another company is a "controlled company" and may elect not to comply with certain NYSE corporate governance requirements, including:

•

the requirement that a majority of our Board of Directors consists of independent directors;

•

the requirement that we have a nominating and corporate governance committee that is composed entirely of independent directors with a written charter addressing the committee's purpose and responsibilities;

•

the requirement that we have a compensation committee that is composed entirely of independent directors with a written charter addressing the committee's purpose and responsibilities; and

•

the requirement for an annual performance evaluation of the nominating and corporate governance and compensation committees.

        Following this offering, we intend to utilize certain of these exemptions. As a result, we will not have a majority of independent directors nor will our nominating and corporate governance and compensation committees consist entirely of independent directors, and we will not be required to have an annual performance evaluation of the nominating and corporate governance and compensation committees. Please read "Management—Composition of Our Board of Directors." Accordingly, you will not have the same protections afforded to stockholders of companies that are subject to such corporate governance requirements.

The corporate opportunity provisions in our amended and restated certificate of incorporation could enable the Apollo Funds, our equity sponsor, to benefit from corporate opportunities that might otherwise be available to us.

        Subject to the limitations of applicable law, our amended and restated certificate of incorporation, among other things:

•

permits us to enter into transactions with entities in which one or more of our officers or directors are financially or otherwise interested;

•

permits any of our stockholders, officers or directors to conduct business that competes with us and to make investments in any kind of property in which we may make investments; and

•

provides that if any director or officer of one of our affiliates who is also one of our officers or directors becomes aware of a potential business opportunity, transaction or other matter (other than one expressly offered to that director or officer in writing solely in his or her capacity as our director or officer), that director or officer will have no duty to communicate or offer that opportunity to us, and will be permitted to communicate or offer that opportunity to such affiliates and that director or officer will not be deemed to have (1) acted in a manner inconsistent with his or her fiduciary or other duties to us regarding the opportunity or (2) acted in bad faith or in a manner inconsistent with our best interests.

        As a result, the Apollo Funds or their affiliates may become aware, from time to time, of certain business opportunities, such as acquisition opportunities, and may direct such opportunities to other businesses in which they have invested, in which case we may not become aware of or otherwise have the ability to pursue such opportunity. Further, such businesses may choose to compete with us for

43

these opportunities. As a result, our renouncing our interest and expectancy in any business opportunity that may be from time to time presented to the Apollo Funds and their affiliates could adversely impact our business or prospects if attractive business opportunities are procured by such parties for their own benefit rather than for ours. Please read "Description of Capital Stock."

We have engaged in transactions with our affiliates and expect to do so in the future. The terms of such transactions and the resolution of any conflicts that may arise may not always be in our or our stockholders' best interests.

        We have engaged in transactions and expect to continue to engage in transactions with affiliated companies, as described under the caption "Certain Relationships and Related Party Transactions." The resolution of any conflicts that may arise in connection with any related party transactions that we have entered into with the Apollo Funds or their affiliates, including pricing, duration or other terms of service, may not always be in our or our stockholders' best interests because the Apollo Funds may have the ability to influence the outcome of these conflicts. For a discussion of potential conflicts, please read "—Our largest stockholder controls a significant percentage of our common stock, and their interests may conflict with those of our other stockholders."

We will incur increased costs as a result of being a public company, which may significantly affect our financial condition.

        As a public company, we will incur significant legal, accounting and other expenses that we did not incur as a private company. We will incur costs associated with our public company reporting requirements. We also anticipate that we will incur costs associated with corporate governance requirements, including requirements under the Sarbanes-Oxley Act, as well as rules implemented by the SEC and the Financial Industry Regulatory Authority. We expect these rules and regulations to increase our legal and financial compliance costs and to make some activities more time-consuming and costly, particularly after we are no longer an "emerging growth company." We also expect these rules and regulations may make it more difficult and more expensive for us to obtain director and officer liability insurance and we may be required to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. As a result, it may be more difficult for us to attract and retain qualified individuals to serve on our Board of Directors or as executive officers.

        We will remain an "emerging growth company" for up to five years. After we are no longer an "emerging growth company," we expect to incur significant additional expenses and devote substantial management effort toward ensuring compliance with those requirements applicable to companies that are not "emerging growth companies," including Section 404 of the Sarbanes-Oxley Act. Please read "—Risks Related to the Oil and Natural Gas Industry and Our Business—We will be subject to certain requirements of Section 404 of the Sarbanes-Oxley Act. If we are unable to timely comply with Section 404 or if the costs related to compliance are significant, our profitability, stock price, results of operations and financial condition could be materially adversely affected."

We are an "emerging growth company" and we cannot be certain if the reduced disclosure requirements applicable to emerging growth companies will make our common stock less attractive to investors.

        We are an "emerging growth company," as defined in the JOBS Act, and we intend to take advantage of certain exemptions from various reporting requirements that are applicable to other public companies, including, but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder

44

approval of any golden parachute payments not previously approved. We intend to take advantage of these reporting exemptions until we are no longer an "emerging growth company." We cannot predict if investors will find our common stock less attractive because we will rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

        We will remain an emerging growth company for up to five years, although we will lose that status sooner if we have more than $1.0 billion of revenues in a fiscal year, have more than $700 million in market value of our common stock held by non-affiliates as of any June 30 or issue more than $1.0 billion of non-convertible debt over a rolling three-year period.

        Under the JOBS Act, "emerging growth companies" can delay adopting new or revised accounting standards until such time as those standards apply to private companies. We have irrevocably elected not to avail ourselves of this exemption from new or revised accounting standards and, therefore, we will be subject to the same new or revised accounting standards as other public companies that are not "emerging growth companies."

        To the extent that we rely on any of the exemptions available to emerging growth companies, you will receive less information about our executive compensation and internal control over financial reporting than issuers that are not emerging growth companies. If some investors find our common stock to be less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

There has been no public market for our common stock and if the price of our common stock fluctuates significantly, your investment could lose value.

        Prior to this offering, there has been no public market for our common stock. Although we have been approved to list our common stock on the NYSE, we cannot assure you that an active public market will develop for our common stock or that our common stock will trade in the public market subsequent to this offering at or above the initial public offering price. If an active public market for our common stock does not develop, the stock price and liquidity of our common stock will be materially and adversely affected. If there is a thin trading market or "float" for our common stock, the market price for our common stock may fluctuate significantly more than the stock market as a whole. Without a large float, our common stock is less liquid than the stock of companies with broader public ownership and, as a result, the stock price of our common stock may be more volatile. In addition, in the absence of an active public trading market, investors may be unable to liquidate their investment in us. The initial offering price, which will be negotiated between us and the underwriters, may not be indicative of the stock price for our common stock after this offering. In addition, the stock market is subject to significant price and volume fluctuations, and the price of our common stock could fluctuate widely in response to several factors, including:

•

our quarterly or annual operating results;

•

changes in our earnings estimates;

•

investment recommendations by securities analysts following our business or our industry;

•

additions or departures of key personnel;

•

changes in the business, earnings estimates or market perceptions of our competitors;

•

our failure to achieve operating results consistent with securities analysts' projections;

•

changes in industry, general market or economic conditions; and

•

announcements of legislative or regulatory change.

45

        The stock market has experienced extreme price and volume fluctuations in recent years that have significantly affected the quoted prices of the securities of many companies, including companies in our industry. The changes often appear to occur without regard to specific operating performance. The price of our common stock could fluctuate based upon factors that have little or nothing to do with our company and these fluctuations could materially reduce our stock price.

Future sales of our common stock, or the perception that such future sales may occur, may cause our stock price to decline.

        Sales of substantial amounts of our common stock in the public market after this offering, or the perception that these sales may occur, could cause the market price of our common stock to decline. Please read "Shares Eligible for Future Sale." In addition, the sale of these shares could impair our ability to raise capital through the sale of additional common or preferred stock. After this offering, we will have                 shares of common stock outstanding, excluding awards under the Athlon Energy Inc. 2013 Incentive Award Plan and New Holdings Units that are exchangeable for shares of our common stock. All of the shares sold in this offering, except for any shares purchased by our affiliates, will be freely tradable.

        The Apollo Funds and our directors and executive officers will be subject to agreements that limit their ability to sell our common stock held by them. These holders cannot sell or otherwise dispose of any shares for a period of at least 180 days after the date of this prospectus without the prior written approval of Citigroup Global Markets Inc. However, these lock-up agreements are subject to certain specific exceptions, including transfers of common stock as a bona fide gift or by will or intestate succession and transfers to such person's immediate family or to a trust or to an entity controlled by such holder, provided that the recipient of the shares agrees to be bound by the same restrictions on sales. In the event that one or more of our stockholders sells a substantial amount of our common stock in the public market, or the market perceives that such sales may occur, the price of our stock could decline.

        As soon as practicable after this offering, we intend to file a registration statement with the SEC on Form S-8 providing for the registration of                  shares of our common stock issued or reserved for issuance under the Athlon Energy Inc. 2013 Incentive Award Plan that we plan to adopt prior to the completion of this offering. Subject to the satisfaction of vesting conditions and the expiration of lock-up agreements, shares registered under our registration statement on Form S-8 will be available for resale immediately in the public market without restriction.

        We cannot predict the size of future issuances of shares of our common stock or the effect, if any, that future issuances and sales of shares of our common stock will have on the market price of our common stock. Sales of substantial amounts of our common stock (including shares issued in connection with an acquisition), or the perception that such sales could occur, may adversely affect prevailing market prices of our common stock.

The underwriters of this offering may waive or release parties to the lock-up agreements entered into in connection with this offering, which could adversely affect the price of our common stock.

        The Apollo Funds and our directors and executive officers have entered into lock-up agreements with respect to their common stock, pursuant to which they are subject to certain resale restrictions for a period of 180 days following the date of this prospectus. Citigroup Global Markets Inc., at any time and without notice, may release all or any portion of the common stock subject to the foregoing lock-up agreements. If the restrictions under the lock-up agreements are waived, then common stock will be available for sale into the public markets, which could cause the market price of our common stock to decline and impair our ability to raise capital.

46

If securities or industry analysts do not publish research or reports about our business, if they adversely change their recommendations regarding our common stock or if our operating results do not meet their expectations, our stock price could decline.

        The trading market for our common stock will be influenced by the research and reports that industry or securities analysts publish about us or our business. If one or more of these analysts cease coverage of our company or fail to publish reports on us regularly, we could lose visibility in the financial markets, which in turn could cause our stock price or trading volume to decline. Moreover, if one or more of the analysts who cover our company downgrades our common stock or if our operating results do not meet their expectations, our stock price could decline.

Purchasers in this offering will experience immediate dilution and will experience further dilution with the future exercise of stock options granted to certain of our executive officers under their respective employment agreements.

        The initial public offering price is substantially higher than the pro forma net tangible book value per share of our outstanding common stock. As a result, you will experience immediate and substantial dilution of approximately $          per share, representing the difference between our net tangible book value per share as of March 31, 2013 after giving effect to this offering and an assumed initial public offering price of $          per share (which is the midpoint of the price range set forth on the cover page of the prospectus). A $1.00 increase (decrease) in the assumed initial public offering price of $          per share (which is the midpoint of the price range set forth on the cover page of this prospectus) would increase (decrease) our net tangible book value per share after giving effect to this offering by $          per share, and increase (decrease) the dilution to new investors by $          per share, assuming the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. If the options granted to certain of our executive officers under their respective employment agreements are exercised in full, the investors in this offering will experience further dilution. Please read "Dilution."

We may issue preferred stock whose terms could adversely affect the voting power or value of our common stock.

        Our amended and restated certificate of incorporation authorizes us to issue, without the approval of our stockholders, one or more classes or series of preferred stock having such designations, preferences, limitations and relative rights, including preferences over our common stock respecting dividends and distributions, as our Board of Directors may determine. The terms of one or more classes or series of preferred stock could adversely impact the voting power or value of our common stock. For example, we might grant holders of preferred stock the right to elect some number of our directors in all events or on the happening of specified events or the right to veto specified transactions. Similarly, the repurchase or redemption rights or liquidation preferences we might assign to holders of preferred stock could affect the residual value of the common stock.

Provisions in our amended and restated certificate of incorporation and amended and restated bylaws and Delaware law make it more difficult to effect a change in control of our company, which could adversely affect the price of our common stock.

        The existence of some provisions in our amended and restated certificate of incorporation and amended and restated bylaws and the DGCL could delay or prevent a change in control of our company, even if that change would be beneficial to our stockholders. Our amended and restated

47

certificate of incorporation and amended and restated bylaws contain provisions that may make acquiring control of our company difficult, including:

•

a classified Board of Directors, so that only approximately one-third of our directors are elected each year;

•

provisions regulating the ability of our stockholders to nominate directors for election or to bring matters for action at annual meetings of our stockholders;

•

limitations on the ability of our stockholders to call a special meeting and act by written consent;

•

the ability of our Board of Directors to adopt, amend or repeal our bylaws;

•

the requirement that the affirmative vote of holders representing at least 66²/3% of the voting power of all outstanding shares of capital stock (or a majority of the voting power of all outstanding shares of capital stock if Apollo beneficially owns at least 33¹/3% of the voting power of all such outstanding shares and votes in favor of the proposed action) be obtained to amend our amended and restated bylaws, to remove directors or to amend our certificate of incorporation; and

•

the authorization given to our Board of Directors to issue and set the terms of preferred stock without the approval of our stockholders.

        These provisions also could discourage proxy contests and make it more difficult for you and other stockholders to elect directors and take other corporate actions. As a result, these provisions could make it more difficult for a third party to acquire us, even if doing so would benefit our stockholders, which may limit the price that investors are willing to pay in the future for our common stock.

We do not intend to pay cash dividends on our common stock in the foreseeable future, and therefore only appreciation of the price of our common stock will provide a return to our stockholders.

        We anticipate that we will retain all future earnings, if any, to finance the growth and development of our business. We do not intend to pay cash dividends in the foreseeable future. Any future determination as to the declaration and payment of cash dividends will be at the discretion of our Board of Directors and will depend upon our financial condition, results of operations, contractual restrictions, capital requirements, business prospects and other factors deemed relevant by our Board of Directors. In addition, the terms of our debt agreements prohibit us from paying dividends and making other distributions. As a result, only appreciation of the price of our common stock, which may not occur, will provide a return to our stockholders.

48

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

        This prospectus contains "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 (the "Securities Act") and Section 21E of the Securities and Exchange Act of 1934 (the "Exchange Act"). Forward-looking statements are subject to a number of risks and uncertainties, many of which are beyond our control. All statements, other than statements of historical fact included in this prospectus, are forward-looking statements. When used in this prospectus, the words "could," "should," "believe," "anticipate," "intend," "estimate," "expect," "may," "continue," "predict," "plan," "potential," "project," "forecast" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words.

        Forward-looking statements may include statements about:

•

our business strategy;

•

our estimated reserves and the present value thereof;

•

our technology;

•

our cash flows and liquidity;

•

our financial strategy, budget, projections and future operating results;

•

realized commodity prices;

•

timing and amount of future production of reserves;

•

availability of drilling and production equipment;

•

availability of pipeline capacity;

•

availability of oilfield labor;

•

the amount, nature and timing of capital expenditures, including future development costs;

•

availability and terms of capital;

•

drilling of wells, including statements made about future horizontal drilling activities;

•

competition;

•

government regulations;

•

marketing of production;

•

exploitation or property acquisitions;

•

costs of exploiting and developing our properties and conducting other operations;

•

general economic and business conditions;

•

competition in the oil and natural gas industry;

•

effectiveness of our risk management activities;

•

environmental and other liabilities;

•

counterparty credit risk;

•

taxation of the oil and natural gas industry;

•

developments in other countries that produce oil and natural gas;

•

uncertainty regarding future operating results;

49

•

plans and objectives of management or our sponsors; and

•

plans, objectives, expectations and intentions contained in this prospectus that are not historical.

        All forward-looking statements speak only as of the date of this prospectus. You should not place undue reliance on these forward-looking statements. Although we believe that our plans, intentions and expectations reflected in or suggested by the forward-looking statements we make in this prospectus are reasonable, we can give no assurance that these plans, intentions or expectations will be achieved when anticipated or at all. We disclose important factors that could cause our actual results to differ materially from our expectations under "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" and elsewhere in this prospectus. These factors include, but are not limited to risks related to:

•

variations in the market demand for, and prices of, oil, natural gas and NGLs;

•

uncertainties about our estimated reserves;

•

the adequacy of our capital resources and liquidity including, but not limited to, access to additional borrowing capacity under our credit agreement;

•

general economic and business conditions;

•

risks associated with negative developments in the capital markets;

•

failure to realize expected value creation from property acquisitions;

•

uncertainties about our ability to replace reserves and economically develop our current reserves;

•

drilling results;

•

potential financial losses or earnings reductions from our commodity price risk management programs;

•

potential adoption of new governmental regulations;

•

the availability of capital on economic terms to fund our capital expenditures and acquisitions;

•

risks associated with our substantial indebtedness; and

•

our ability to satisfy future cash obligations and environmental costs.

        These cautionary statements qualify all forward-looking statements attributable to us or persons acting on our behalf.

        There are numerous uncertainties inherent in estimating quantities of proved reserves and in projecting future rates of production and timing of development expenditures. Oil and natural gas reserve engineering is and must be recognized as a subjective process of estimating underground accumulations of oil and natural gas that cannot be measured in any exact way, and estimates of other engineers might differ materially from those included herein. The accuracy of any reserve estimate is a function of the quality of available data and of engineering and geological interpretation, and estimates may justify revisions based on the results of drilling, testing and production activities. Accordingly, reserve estimates are often materially different from the quantities of oil and natural gas that are ultimately recovered.

50

USE OF PROCEEDS

        We expect the net proceeds from this offering to be approximately $278.5 million, assuming an initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus) and after deducting estimated underwriting discounts and commissions and estimated offering expenses of approximately $21.5 million, in the aggregate. Each $1.00 increase (decrease) in the public offering price would increase (decrease) our net proceeds by approximately $           million.

        We intend to use the net proceeds of this offering, after deducting estimated underwriting discounts and comissions and estimated offering expenses, to purchase New Holdings Units from Athlon Holdings LP. The table below sets forth the anticipated use by Athlon Holdings LP of the net proceeds received by it as a result of our purchase of the New Holdings Units:

	Net Proceeds		Percentage of Net Proceeds
	(in thousands)
Reduce outstanding indebtedness under our credit agreement	$	62,500		22	%
Provide additional liquidity for use in our drilling program		216,000		78	%
Total	$	278,500		100	%

        Remaining net proceeds, if any, will be used for working capital and general corporate purposes, including potential acquisitions.

        As of July 12, 2013, we had $62.5 million of outstanding borrowings under our credit agreement. Our credit agreement matures on March 19, 2018 and bears interest at a variable rate, which was approximately 1.7% as of July 12, 2013. The borrowings to be repaid were incurred primarily to fund our acquisitions and development program. Amounts repaid under our credit agreement may be reborrowed at any time.

        We will not receive any proceeds from sales by the Apollo Funds pursuant to the underwriters' option to purchase additional shares of common stock.

        Affiliates of certain of the underwriters are lenders under our credit agreement and, accordingly, will receive a portion of the net proceeds from this offering. Please read "Underwriting (Conflicts of Interest)."

DIVIDEND POLICY

        We do not anticipate declaring or paying any cash dividends to holders of our common stock in the foreseeable future. We intend to retain future earnings, if any, to finance the expansion of our business. Our future dividend policy is within the discretion of our Board of Directors and will depend upon various factors, including our results of operations, financial condition, capital requirements and investment opportunities. In addition, our debt agreements restrict our ability to pay cash dividends to holders of our common stock.

51

CAPITALIZATION

        The following table sets forth the cash and capitalization as of March 31, 2013 of:

•

Athlon Holdings LP; and

•

Athlon Energy Inc. on a pro forma as adjusted basis to give effect to (1) the reorganization transactions described under "Corporate Reorganization," (2) the offering by Athlon Holdings LP of $500 million of 7³/8% senior notes due 2021 in April 2013, and the application of the net proceeds thereof, and (3) the sale of shares of our common stock in this offering at an assumed initial public offering price of $          per share (which is the midpoint of the price range set forth on the cover page of this prospectus), our receipt of an estimated $278.5 million of net proceeds from this offering after deducting estimated underwriting discounts and commissions and estimated offering expenses and the use of those net proceeds as described under the caption "Use of Proceeds."

        You should read the following table in conjunction with "Management's Discussion and Analysis of Financial Condition and Results of Operations" and our consolidated financial statements and related notes appearing elsewhere in this prospectus.

	As of March 31, 2013
	Athlon Holdings LP1 Actual		Athlon Energy Inc. Pro Forma As Adjusted1,2
	(in thousands)
Cash and cash equivalents	$	3,379	$	275,103
Debt:
Credit agreement3	$	291,426	$	—
Former second lien term loan agreement4		125,000		—
73/8% senior notes due 2021		—		500,000
Total debt		416,426		500,000
Partners' equity		433,330		—
Stockholders' equity:
Preferred stock, $0.01 per share; 50,000,000 shares authorized, no shares issued and outstanding (pro forma as adjusted)		—		—
Common stock, $0.01 par value; 500,000,000 shares authorized (pro forma as adjusted) ;                 shares issued and outstanding (pro forma as adjusted)		—		10
Additional paid-in capital		—		626,182
Accumulated deficit5		—		(22,773	)
Total stockholders' equity		—		606,419
Noncontrolling interest		—		9,429
Total equity		433,330		612,848
Total capitalization	$	849,756	$	1,112,848

¹

Athlon Energy Inc. was incorporated on April 1, 2013 in Delaware as a holding company and will not conduct any material business operations prior to the completion of this offering. The data in this table has been derived from the historical consolidated financial statements and other financial information included in this prospectus which pertain to the assets, liabilities, revenues and expenses of Athlon Holdings LP, our accounting predecessor.

²

Each $1.00 increase (decrease) in the public offering price would increase (decrease) our net proceeds from this offering by approximately $           million.

³

As of July 12, 2013, we had $62.5 million of outstanding borrowings under our credit agreement.

⁴

We used a portion of the net proceeds from the senior notes offering to repay in full and terminate our former second lien term loan agreement.

⁵

Upon completion of our corporate reorganization, we will recognize deferred tax liabilities and assets for temporary differences between the historical cost basis and tax basis of our assets and liabilities. Based on estimates of those temporary differences as of March 31, 2013, a net deferred tax liability of approximately $19.0 million will be recognized with a corresponding charge to earnings.

52

DILUTION

        Purchasers of our common stock in this offering will experience immediate and substantial dilution in the net tangible book value per share of the common stock for accounting purposes. Our net tangible book value (tangible assets less total liabilities) as of March 31, 2013, after giving pro forma effect to the transactions described under "Corporate Reorganization," and our senior notes offering, was approximately $           million, or $        per share of common stock. Pro forma net tangible book value per share is determined by dividing our pro forma net tangible book value by our shares of common stock that will be outstanding immediately prior to the closing of this offering, including giving effect to the reorganization transactions described under "Corporate Reorganization" and our senior notes offering. Assuming an initial public offering price of $          per share (which is the midpoint of the price range set forth on the cover page of this prospectus), after giving effect to the sale of the shares in this offering and further assuming the receipt of the estimated net proceeds (after deducting estimated underwriting discounts and commissions and estimated offering expenses), our adjusted pro forma net tangible book value as of March 31, 2013 would have been approximately $           million, or $          per share. This represents an immediate increase in the net tangible book value of $          per share to our existing stockholders and an immediate dilution to new investors purchasing shares in this offering of $          per share, resulting from the difference between the offering price and the pro forma as adjusted net tangible book value after this offering. The following table illustrates the per share dilution to new investors purchasing shares in this offering:

Assumed initial public offering price per share		$
Pro forma net tangible book value per share as of March 31, 2013 (prior to this offering)	$
Increase per share attributable to new investors in the offering
As adjusted pro forma net tangible book value per share (after this offering)
Dilution in pro forma net tangible book value per share to new investors in this offering1		$

¹

If the initial public offering price were to increase or decrease by $1.00 per share, then dilution in pro forma net tangible book value per share to new investors in this offering would equal $          or $          , respectively.

        The following table sets forth, as of March 31, 2013, the number of shares of common stock held by our existing stockholders immediately prior to the closing of this offering, and by the new investors at the assumed initial public offering price of $          per share (which is the midpoint of the price range set forth on the cover page of this prospectus), together with the total consideration paid and average price per share paid by each of these groups, before deducting estimated underwriting discounts and commissions and estimated offering expenses:

	Shares Purchased				Total Consideration
									Average Price Per Share
	Number	Percent			Amount	Percent
					(in millions)
Existing stockholders				%	$			%	$
New investors				%				%
Total			100.0	%	$		100.0	%

        The data in the table excludes                 shares of common stock initially reserved for issuance under the Athlon Energy Inc. 2013 Incentive Award Plan (which amount may be increased each year in accordance with the terms of the plan).

        If the underwriters' option to purchase additional shares of common stock from the Apollo Funds is exercised in full, the number of shares held by new investors will be increased to                 , or approximately          % of our outstanding shares of common stock.

53

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA

        The following selected consolidated balance sheets data, statements of operations data and statements of cash flows data as of and for the years ended December 31, 2012 and 2011 are derived from, and qualified by reference to, the audited consolidated financial statements of Athlon Holdings LP, our accounting predecessor, included elsewhere in this prospectus and should be read in conjunction with those financial statements and notes thereto as well as "Management's Discussion and Analysis of Financial Condition and Results of Operations." The following selected consolidated balance sheet data as of March 31, 2013 and the consolidated statements of operations data and statements of cash flow data for the three months ended March 31, 2013 and 2012 are derived from, and qualified by reference to, the unaudited consolidated financial statements of Athlon Holdings LP, our accounting predecessor, included elsewhere in this prospectus and should be read in conjunction with those financial statements and notes thereto as well as "Management's Discussion and Analysis of Financial Condition and Results of Operations." The financial information included in this prospectus may not be indicative of our future results of operations, financial position and cash flows.

	Three months ended March 31,						Year ended December 31,
	2013			2012			2012			2011
	(unaudited)
	(in thousands)
Consolidated Statements of Operations Data:
Revenues:
Oil	$	45,659		$	27,433		$	128,081		$	51,193
Natural gas		3,367			1,448			8,415			3,521
NGLs		5,720			4,351			20,615			10,967
Total revenues		54,746			33,232			157,111			65,681
Expenses:
Production:
Lease operating		7,237			4,699			25,503			13,328
Production, severance and ad valorem taxes		3,694			2,350			10,438			4,727
Depletion, depreciation and amortization		18,053			9,614			54,456			19,747
General and administrative		3,282			2,597			9,678			7,724
Acquisition costs		57			—			876			9,519
Derivative fair value loss (gain)		6,849			22,711			(9,293	)		7,959
Other operating		194			130			562			404
Total expenses		39,366			42,101			92,220			63,408
Operating income (loss)		15,380			(8,869	)		64,891			2,273
Interest expense		4,474			1,495			9,949			2,932
Income (loss) before income taxes		10,906			(10,364	)		54,942			(659	)
Income tax provision (benefit)		27			(364	)		1,928			470
Net income (loss)	$	10,879		$	(10,000	)	$	53,014		$	(1,129	)
Consolidated Statements of Cash Flows Data:
Cash provided by (used in):
Operating activities	$	30,397		$	20,723		$	95,302		$	18,872
Investing activities		(90,560	)		(58,498	)		(347,259	)		(465,475	)
Financing activities		54,671			12,982			228,798			471,627
Consolidated Balance Sheets Data (at period end):
Cash and cash equivalents	$	3,379					$	8,871		$	32,020
Total assets		916,535						852,298			561,823
Total debt		416,426						362,000			170,000
Partners' equity		433,330						420,877			327,452

54

MANAGEMENT'S DISCUSSION AND ANALYSIS OF
FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our consolidated financial statements and related notes appearing elsewhere in this prospectus. The following discussion and analysis contains forward-looking statements, including, without limitation, statements relating to our plans, strategies, objectives, expectations, intentions and resources. Actual results could differ materially from those discussed in these forward-looking statements. We do not undertake to update, revise or correct any of the forward-looking information unless required to do so under federal securities laws. Readers are cautioned that such forward-looking statements should be read in conjunction with our disclosures under "Cautionary Note Regarding Forward-Looking Statements" and "Risk Factors" appearing elsewhere in this prospectus.

Overview

        We are an independent exploration and production company focused on the acquisition, development and exploitation of unconventional oil and liquids-rich natural gas reserves in the Permian Basin. The Permian Basin spans portions of Texas and New Mexico and consists of three primary sub-basins: the Delaware Basin, the Central Basin Platform and the Midland Basin. All of our properties are located in the Midland Basin. Our drilling activity is currently focused on the low-risk vertical development of stacked pay zones, including the Spraberry, Wolfcamp, Cline, Strawn, Atoka and Mississippian formations, which we refer to collectively as the Wolfberry play. We are a returns-focused organization and have targeted the Wolfberry play in the Midland Basin because of its favorable operating environment, consistent reservoir quality across multiple target horizons, long-lived reserve characteristics and high drilling success rates.

        We were founded in August 2010 by a group of executives from Encore Acquisition Company following its acquisition by Denbury Resources, Inc. With an average of approximately 20 years of industry experience and over 10 years of history working together, our founding management has a proven track record of working as a team to acquire, develop and exploit oil and natural gas reserves in the Permian Basin as well as other resource plays in North America.

        Our acreage position was 124,925 gross (98,348 net) acres at May 31, 2013, which we group into three primary areas based on geographic location within the Midland Basin: Howard, Midland & Other and Glasscock. From the time we began operations in January 2011 through May 31, 2013, we have operated up to eight vertical drilling rigs simultaneously and have drilled 230 gross vertical Wolfberry wells with a 99% success rate across all three areas. This activity has allowed us to identify and de-risk our multi-year inventory of 4,902 gross (3,857 net) vertical drilling locations, while also identifying 1,079 gross (931 net) horizontal drilling locations in specific areas based on the geophysical and technical data as of May 31, 2013. As we continue to expand our vertical drilling activity to our undeveloped acreage, we expect to identify additional horizontal drilling locations.

        As of December 31, 2012, we had 86 MMBOE of proved reserves. In addition, we have grown our production to 10,971 BOE/D for April 2013. As of December 31, 2012, our estimated proved reserves were approximately 58% oil, 22% NGLs and 20% natural gas and approximately 30% were proved developed reserves. Our PUDs include 597 gross (560 net) potential vertical drilling locations.

Our Acquisition History

        A significant portion of our historical growth has been achieved through acquisitions. Since our inception in August 2010, we have completed two significant acquisitions and seven bolt-on acquisitions. At the time of each acquisition, based on internal engineering estimates, these properties collectively contributed approximately 3,600 BOE/D of production and approximately 43 MMBOE of proved reserves.

55

        On January 6, 2011, we acquired certain oil and natural gas properties and related assets, consisting of 19,210 gross (18,833 net) acres in the Permian Basin in West Texas, from SandRidge Exploration and Production, LLC ("SandRidge," and when discussing the transaction, the "SandRidge acquisition") for $156.0 million in cash, which was financed through borrowings under our credit agreement and capital contributions from partners. The SandRidge properties included approximately 1,600 BOE/D of production and approximately 19.1 MMBOE of proved reserves at the time of acquisition based on internal reserve reports.

        On October 3, 2011, we acquired certain oil and natural gas properties and related assets, consisting of 41,044 gross (34,400 net) acres in the Permian Basin in West Texas, from Element Petroleum, LP ("Element," and when discussing the transaction, the "Element acquisition") for $253.2 million in cash, which was financed through borrowings under our credit agreement and capital contributions from partners. The Element properties included approximately 1,400 BOE/D of production and approximately 16.4 MMBOE of proved reserves at the time of acquisition based on internal reserve reports.

Factors That Significantly Affect Our Financial Condition and Results of Operations

        Our revenues, cash flow from operations and future growth depend substantially on factors beyond our control, such as economic, political and regulatory developments and competition from other sources of energy. Oil and natural gas prices have historically been volatile and may fluctuate widely in the future due to a variety of factors, including but not limited to, prevailing economic conditions, supply and demand of hydrocarbons in the marketplace, actions by speculators and geopolitical events such as wars or natural disasters. Sustained periods of low prices for oil, natural gas or NGLs could materially and adversely affect our financial condition, our results of operations, the quantities of oil and natural gas that we can economically produce and our ability to access capital.

        We use commodity derivative instruments, such as swaps, puts and collars to manage and reduce price volatility and other market risks associated with our oil production. These arrangements are structured to reduce our exposure to commodity price decreases, but they can also limit the benefit we might otherwise receive from commodity price increases. Our risk management activity is generally accomplished through over-the-counter commodity derivative contracts with large financial institutions. We elected not to designate our current portfolio of commodity derivative contracts as hedges. Therefore, changes in fair value of these derivative instruments are recognized in earnings. Please read "—Quantitative and Qualitative Disclosures About Market Risk" for additional discussion of our commodity derivative contracts.

        The prices we realize on the oil we produce are affected by the ability to transport crude oil to the Cushing, Oklahoma transport hub and the Gulf Coast refineries. Periodically, logistical and infrastructure constraints at the Cushing, Oklahoma transport hub have resulted in an oversupply of crude oil at Midland, Texas and thus lower prices for Midland WTI. These lower prices have adversely affected the prices we realize on oil sales and increased our differential to NYMEX WTI. However, several projects have recently been implemented and several more are underway to ease these transportation difficulties which we believe could reduce our differentials to NYMEX in the future. We have also entered into Midland-Cushing differential swaps for 2013 to mitigate the adverse effects of any further widening of the Midland-Cushing WTI differential (the difference between Midland WTI and Cushing WTI).

        Like all businesses engaged in the exploration and production of oil and natural gas, we face the challenge of natural production declines. As initial reservoir pressures are depleted, oil and natural gas production from a given well naturally decreases. Thus, an oil and natural gas exploration and production company depletes part of its asset base with each unit of oil or natural gas it produces. We attempt to overcome this natural decline by drilling to find additional reserves and acquiring more

56

reserves than we produce. Our future growth will depend on our ability to enhance production levels from our existing reserves and to continue to add reserves in excess of production in a cost effective manner. Our ability to make capital expenditures to increase production from our existing reserves and to add reserves through drilling is dependent on our capital resources and can be limited by many factors, including our ability to access capital in a cost-effective manner and to timely obtain drilling permits and regulatory approvals.

        As with our historical acquisitions, any future acquisitions could have a substantial impact on our financial condition and results of operations. In addition, funding future acquisitions may require us to incur additional indebtedness or issue additional equity.

        The volumes of oil and natural gas that we produce are driven by several factors, including:

•

success in drilling wells, including exploratory wells, and the recompletion of existing wells;

•

the amount of capital we invest in the leasing and development of our oil and natural gas properties;

•

facility or equipment availability and unexpected downtime;

•

delays imposed by or resulting from compliance with regulatory requirements; and

•

the rate at which production volumes on our wells naturally decline.

Factors That Significantly Affect Comparability of Our Financial Condition and Results of Operations

        Our historical financial condition and results of operations for the periods presented may not be comparable, either from period to period or going forward, for the following reasons:

        Corporate Reorganization.    The historical consolidated financial statements included in this prospectus are based on the financial statements of Athlon Holdings LP, our accounting predecessor, prior to the reorganization transactions as described under "Corporate Reorganization." As a result, the historical financial data may not give you an accurate indication of what our actual results would have been if the reorganization transactions had been completed at the beginning of the periods presented or what our future results of operations are likely to be.

        Public Company Expenses.    Upon completion of this offering, we expect to incur direct, incremental general and administrative ("G&A") expenses as a result of being a publicly traded company, including, but not limited to, costs associated with annual and quarterly reports to stockholders, tax return preparation, independent auditor fees, investor relations activities, registrar and transfer agent fees, incremental director and officer liability insurance costs and independent director compensation. We estimate these direct, incremental G&A expenses initially to total approximately $2.0 million per year. These direct, incremental G&A expenses are not included in our historical results of operations.

        Income Taxes.    Athlon Holdings LP, our accounting predecessor, was a limited partnership not subject to federal income taxes. Accordingly, no provision for federal income taxes has been provided for in our historical results of operations because taxable income was passed through to Athlon Holdings LP's partners. However, we are a corporation under the Internal Revenue Code, subject to federal income taxes at a statutory rate of 35% of pretax earnings.

        Increased Drilling Activity.    We began operations in January 2011 and gradually added operated vertical drilling rigs. We currently operate seven vertical drilling rigs on our properties, and we have operated between five and eight drilling rigs since October 2011. Our 2013 development capital budget is approximately $317 million, including $15 million for infrastructure, leasing and capitalized workovers, and we expect to drill 162 gross (150 net) vertical Wolfberry wells. We also plan to invest

57

$33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells. We expect to take delivery of our first horizontal rig in the third quarter of 2013. In 2014, we intend to expand to an eight-rig vertical drilling program. In addition, we intend to implement a horizontal drilling program in the second half of 2013 which we expect will significantly increase our capital expenditures in future periods. The ultimate amount of capital that we expend may fluctuate materially based on market conditions and our drilling results in each particular year.

        Element Acquisition.    On October 3, 2011, we acquired certain oil and natural gas properties and related assets, consisting of 41,044 gross (34,400 net) acres in the Element acquisition for $253.2 million in cash, which was financed through borrowings under our credit agreement and capital contributions from partners. Only three months of production from the Element properties is included in our results of operations for 2011.

        Financing Arrangements.    Through March 31, 2013, we had incurred $416.4 million of indebtedness, including $291.4 million under our credit agreement and $125 million under a second lien term loan agreement, which we refer to as our former second lien term loan. In April 2013, we issued $500 million in aggregate principal amount of 7³/8% senior notes due 2021. We used the proceeds of our senior notes offering to repay a portion of the amounts outstanding under our credit agreement, to repay in full and terminate our former second lien term loan, to make a $75 million distribution to Class A limited partners of Athlon Holdings LP and for general corporate purposes. Our senior notes bear interest at a rate significantly higher than the rates under our credit agreement which will result in higher interest expense in future periods as compared to our historical interest expense. In the future, we may incur additional indebtedness to fund our acquisition and development activities. Please read "—Capital Commitments, Capital Resources, and Liquidity—Liquidity" for additional discussion of our financing arrangements.

Sources of Our Revenues

        Our revenues are derived from the sale of oil, natural gas and NGLs within the continental United States and do not include the effects of derivatives. For 2012, oil and NGLs represented approximately 80% of our total production volumes. Our revenues may vary significantly from period to period as a result of changes in volumes of production sold or changes in commodity prices.

        NYMEX WTI and Henry Hub prompt month contract prices are widely-used benchmarks in the pricing of oil and natural gas. The following table provides the high and low prices for NYMEX WTI and Henry Hub prompt month contract prices and our differential to the average of those benchmark prices for the periods indicated:

	Three months ended March 31,						Year ended December 31,
	2013			2012			2012			2011
Oil
NYMEX WTI High	$	97.94		$	109.77		$	109.77		$	113.93
NYMEX WTI Low		90.12			96.36			77.69			75.67
Differential to Average NYMEX WTI		(10.11	)		(3.66	)		(6.29	)		(3.03	)
Natural Gas
NYMEX Henry Hub High		4.07			3.10			3.90			4.85
NYMEX Henry Hub Low		3.11			2.13			1.91			2.99
Differential to Average NYMEX Henry Hub		(0.07	)		(0.03	)		(0.13	)		(0.54	)

        We normally sell production to a relatively small number of customers. In 2012, three purchasers individually accounted for more than 10% of our revenues: Pecos Gathering & Marketing (43%); Occidental Petroleum Corporation (29%); and DCP Midstream (12%). If any significant customer

58

decided to stop purchasing oil and natural gas from us, our revenues could decline and our operating results and financial condition could be harmed. However, based on the current demand for oil and natural gas, and the availability of other purchasers, we believe that the loss of any one or all of our significant customers would not have a material adverse effect on our financial condition and results of operations, as crude oil and natural gas are fungible products with well-established markets and numerous purchasers.

Principal Components of Our Cost Structure

        Lease Operating Expense.    LOE includes the daily costs incurred to bring crude oil and natural gas out of the ground and to the market, together with the daily costs incurred to maintain our producing properties. Such costs include field personnel compensation, utilities, maintenance and workover expenses related to our oil and natural gas properties.

        Production, Severance and Ad Valorem Taxes.    Production and severance taxes are paid on produced oil, natural gas and NGLs based on a percentage of revenues from production sold at fixed rates established by federal, state or local taxing authorities. In general, the production and severance taxes we pay correlate to the changes in oil and natural gas revenues. We are also subject to ad valorem taxes in the counties where our production is located. Ad valorem taxes are generally based on the valuation of our oil and natural gas properties and are assessed annually.

        Depreciation, Depletion and Amortization.    Depreciation, depletion and amortization ("DD&A") is the expensing of the capitalized costs incurred to acquire, explore and develop oil and natural gas. We use the full cost method of accounting for oil and natural gas activities. Please read "—Critical Accounting Policies and Estimates—Method of Accounting for Oil and Natural Gas Properties" for further discussion.

        General and Administrative Expense.    G&A expense consists of company overhead, including payroll and benefits for our corporate staff, costs of maintaining our headquarters, costs of managing our production and development operations, audit and other professional fees and legal compliance costs. Upon completion of this offering, G&A expense will also include public company expenses as described above under "—Factors That Significantly Affect Comparability of Our Financial Condition and Results of Operations—Public Company Expenses."

        Interest Expense.    We finance a portion of our working capital requirements, capital expenditures and acquisitions with borrowings under our credit agreement. As a result, we incur interest expense that is affected by both fluctuations in interest rates and our financing decisions. Interest incurred under our debt agreements, the amortization of deferred financing costs (including origination and amendment fees), commitment fees and annual agency fees are included in interest expense. Interest expense is net of capitalized interest on expenditures made in connection with exploration and development projects that are not subject to current amortization. Interest expense will also include interest incurred under our senior notes beginning April 2013 as described above under "—Factors That Significantly Affect Comparability of Our Financial Condition and Results of Operations—Financing Arrangements."

        Derivative Fair Value Loss (Gain).    We utilize commodity derivative contracts to reduce our exposure to fluctuations in the price of oil. We recognize unrealized gains and losses associated with our open commodity derivative contracts as commodity prices and the associated fair value of our commodity derivative contracts change. The commodity derivative contracts we have in place are not designated as hedges for accounting purposes. Consequently, these commodity derivative contracts are marked-to-market each quarter with fair value gains and losses, both realized and unrealized, recognized currently as a gain or loss in our results of operations. Cash flow is only impacted to the

59

extent the actual settlements under the contracts result in making a payment to or receiving a payment from the counterparty.

How We Evaluate Our Operations

        In evaluating our financial results, we focus on the mix of our revenues from oil, natural gas and NGLs, the average realized price from sales of our production, our production margins and our net income. Below are highlights of our financial and operating results for the first quarter of 2013:

•

Our oil, natural gas and NGLs revenues increased 65% to $54.7 million in the first quarter of 2013 as compared to $33.2 million in the first quarter of 2012.

•

Our average daily production volumes increased 94% to 9,959 BOE/D in the first quarter of 2013 as compared to 5,140 BOE/D in the first quarter of 2012. Oil and NGLs represented approximately 81% of our total production volumes in the first quarter of 2013.

•

Our average realized oil price decreased 15% to $84.23 per Bbl in the first quarter of 2013 as compared to $99.29 per Bbl in the first quarter of 2012. Our average realized natural gas price increased 21% to $3.27 per Mcf in the first quarter of 2013 as compared to $2.71 per Mcf in the first quarter of 2012. Our average realized NGL price decreased 26% to $31.34 per Bbl in the first quarter of 2013 as compared to $42.48 per Bbl in the first quarter of 2012.

•

Our production margin increased 67% to $43.8 million in the first quarter of 2013 as compared to $26.2 million in the first quarter of 2012. Total wellhead revenues per BOE decreased by 14% and total production expenses per BOE decreased by 19%. On a per BOE basis, our production margin decreased 13% to $48.84 per BOE in the first quarter of 2013 as compared to $55.92 per BOE for the first quarter of 2012.

•

Our net income was $10.9 million as compared to a net loss of $10.0 million for the first quarter of 2012.

•

We invested $80.9 million in oil and natural gas activities, of which $71.8 million was invested in development and exploration activities, yielding 35 gross (34 net) productive wells, and $9.1 million was invested in acquisitions.

        We also evaluate our rates of return on invested capital in our wells. We believe the quality of our assets combined with the technical capabilities of our management team can generate attractive rates of return as we develop our extensive resource base. Additionally, by focusing on concentrated acreage positions, we can build and own centralized production infrastructure, including saltwater disposal facilities, which enable us to reduce reliance on outside service companies, minimize costs and increase our returns.

        We measure the expected return of our wells based on EUR and the related costs of acquisition, development and production. Based on estimates prepared by our independent reserve engineers, as of December 31, 2012, the wells we expect to drill in 2013 through the Atoka formation in Howard, Midland & Other and Glasscock areas have an average EUR of 141 MBOE (87 MBbls of oil, 150 MMcf of natural gas and 30 MBbls of NGLs), 208 MBOE (95 MBbls of oil, 318 MMcf of natural gas and 60 MBbls of NGLs) and 118 MBOE (73 MBbls of oil, 141 MMcf of natural gas and 22 MBbls of NGLs), respectively. Our average drilling and completion cost per vertical well drilled in the Howard, Midland & Other and Glasscock areas in the fourth quarter of 2012 was $1.8 million, $2.15 million and $1.8 million, respectively, with average 30-day initial production rates of approximately 130 BOE/D, 190 BOE/D and 100 BOE/D, respectively. Assuming a benchmark crude oil price of $94.71 per Bbl and natural gas price of $2.75 per Mcf, the PUD wells we expect to drill in 2013 in the Howard, Midland & Other and Glasscock areas are targeted to produce an average rate of return of 34%, 43% and 21%, respectively.

60

Results of Operations

Comparison of Quarter Ended March 31, 2013 to Quarter Ended March 31, 2012

        Revenues.    The following table provides the components of our revenues for the periods indicated, as well as each period's respective production volumes and average prices:

	Three months ended March 31,				Increase / (Decrease)
	2013		2012		$			%
Revenues (in thousands):
Oil	$	45,659	$	27,433	$	18,226			66	%
Natural gas		3,367		1,448		1,919			133	%
NGLs		5,720		4,351		1,369			31	%
Total revenues	$	54,746	$	33,232	$	21,514			65	%
Average realized prices:
Oil ($/Bbl) (excluding impact of cash settled derivatives)	$	84.23	$	99.29	$	(15.06	)		-15	%
Oil ($/Bbl) (after impact of cash settled derivatives)	$	83.97	$	89.91	$	(5.94	)		-7	%
Natural gas ($/Mcf)	$	3.27	$	2.71	$	0.56			21	%
NGLs ($/Bbl)	$	31.34	$	42.48	$	(11.14	)		-26	%
Combined ($/BOE) (excluding impact of cash settled derivatives)	$	61.08	$	71.05	$	(9.97	)		-14	%
Combined ($/BOE) (after impact of cash settled derivatives)	$	60.92	$	65.50	$	(4.58	)		-7	%
Total production volumes:
Oil (MBbls)		542		276		266			96	%
Natural gas (MMcf)		1,030		534		496			93	%
NGLs (MBbls)		183		102		81			79	%
Combined (MBOE)		896		468		428			91	%
Average daily production volumes:
Oil (Bbls/D)		6,023		3,036		2,987			98	%
Natural gas (Mcf/D)		11,446		5,871		5,575			95	%
NGLs (Bbls/D)		2,028		1,125		903			80	%
Combined (BOE/D)		9,959		5,140		4,819			94	%

        The following table shows the relationship between our average oil and natural gas realized prices as a percentage of average NYMEX prices for the periods indicated. Management uses the realized price to NYMEX margin analysis to analyze trends in our oil and natural gas revenues.

	Three months ended March 31,
	2013			2012
Average realized oil price ($/Bbl)	$	84.23		$	99.29
Average NYMEX ($/Bbl)	$	94.34		$	102.95
Differential to NYMEX	$	(10.11	)	$	(3.66	)
Average realized oil price to NYMEX percentage		89	%		96	%
Average realized natural gas price ($/Mcf)	$	3.27		$	2.71
Average NYMEX ($/Mcf)	$	3.34		$	2.74
Differential to NYMEX	$	(0.07	)	$	(0.03	)
Average realized natural gas price to NYMEX percentage		98	%		99	%

61

        Our average realized oil price as a percentage of the average NYMEX price was 89% for the first quarter of 2013 as compared to 96% for the first quarter of 2012. All of our oil contracts include the Midland-Cushing differential, which widened to a negative $7.78 per Bbl in the first quarter of 2013 as compared to a negative $1.51 per Bbl in the first quarter of 2012 primarily due to difficulty transporting oil from the Permian Basin to the Gulf Coast refineries due to lack of logistics and infrastructure. However, several projects have recently been implemented and several more are underway to ease these transportation difficulties which we believe will reduce our differentials to NYMEX in the future. We began to see a tightening of our oil differentials in March and have continued to see improvement into the second quarter of 2013 where the differential has decreased to a negative $0.18 per Bbl average for May 2013. Our average realized natural gas price as a percentage of the average NYMEX price remained stable at 98% for the first quarter of 2013 as compared to 99% for the first quarter of 2012.

        Oil revenues increased 66% from $27.4 million in the first quarter of 2012 to $45.7 million in the first quarter of 2013 as a result of an increase in our oil production volumes of 266 MBbls, partially offset by a $15.06 per Bbl decrease in our average realized oil price. Our higher oil production increased oil revenues by $26.4 million and was primarily the result of our development program in the Permian Basin. Our lower average realized oil price decreased oil revenues by $8.2 million and was primarily due to a lower average NYMEX price, which decreased from $102.95 per Bbl in the first quarter of 2012 to $94.34 per Bbl in the first quarter of 2013, and the widening of our oil differentials as previously discussed.

        Natural gas revenues increased 133% from $1.4 million in the first quarter of 2012 to $3.4 million in the first quarter of 2013 as a result of an increase in our natural gas production volumes of 496 MMcf and a $0.56 per Mcf increase in our average realized natural gas price. Our higher natural gas production increased natural gas revenues by $1.4 million and was primarily the result of our development program in the Permian Basin, partially offset by flaring a portion of our natural gas production as either (1) our well is not yet tied into the third-party gathering system, (2) the pressures on the third-party gathering system are too high to allow additional production from our well to be transported or (3) our production is prorated due to high demand on the third-party gathering system. During the first quarter of 2013, we flared an average of approximately 2.0 MMcf/D, or 331 BOE/D, of natural gas, which included both residue gas and NGL production. We expect to continue flaring approximately 3.0 MMcf/D to 4.0 MMcf/D until further improvements can be made to various gathering systems near our wells, which is scheduled to occur in mid-2013. Our higher average realized natural gas price increased natural gas revenues by $0.6 million and was primarily due to a higher average NYMEX price, which increased from $2.74 per Mcf in the first quarter of 2012 to $3.34 per Mcf in the first quarter of 2013.

        NGL revenues increased 31% from $4.4 million in the first quarter of 2012 to $5.7 million in the first quarter of 2013 as a result of an increase in our NGL production volumes of 81 MBbls, partially offset by an $11.14 per Bbl decrease in our average realized NGL price. Our higher NGL production increased NGL revenues by $3.4 million and was primarily the result of our development program in the Permian Basin, partially offset by flaring a portion of our natural gas as described above. Our lower average realized NGL price decreased NGL revenues by $2.0 million and was primarily due to increased supplies of NGLs from NGL-rich shales in the Permian Basin and other basins including the Eagle Ford and the Williston.

62

        Expenses.    The following table summarizes our expenses for the periods indicated:

	Three months ended March 31,					Increase / (Decrease)
	2013		2012			$			%
Expenses (in thousands):
Production:
Lease operating	$	7,237	$	4,699		$	2,538			54	%
Production, severance and ad valorem taxes		3,694		2,350			1,344			57	%
Processing, gathering and overhead		45		24			21			88	%
Total production expenses		10,976		7,073			3,903			55	%
Other:
Depletion, depreciation and amortization		18,053		9,614			8,439			88	%
General and administrative		3,339		2,597			742			29	%
Derivative fair value loss—cash settlements		141		2,593			(2,452	)		-95	%
Derivative fair value loss—non-cash mark-to-market		6,708		20,118			(13,410	)		-67	%
Accretion		149		106			43			41	%
Total operating		39,366		42,101			(2,735	)		-6	%
Interest		4,474		1,495			2,979			199	%
Income tax provision (benefit)		27		(364	)		391			-107	%
Total expenses	$	43,867	$	43,232		$	635			1	%
Expenses (per BOE):
Production:
Lease operating	$	8.07	$	10.05		$	(1.98	)		-20	%
Production, severance and ad valorem taxes		4.12		5.03			(0.91	)		-18	%
Processing, gathering and overhead		0.05		0.05			—			0	%
Total production expenses		12.24		15.13			(2.89	)		-19	%
Other:
Depletion, depreciation and amortization		20.14		20.55			(0.41	)		-2	%
General and administrative		3.73		5.55			(1.82	)		-33	%
Derivative fair value loss—cash settlements		0.16		5.54			(5.38	)		-97	%
Derivative fair value loss—non-cash mark-to-market		7.48		43.01			(35.53	)		-83	%
Accretion		0.17		0.23			(0.06	)		-26	%
Total operating		43.92		90.01			(46.09	)		-51	%
Interest		4.99		3.20			1.79			56	%
Income tax provision (benefit)		0.03		(0.78	)		0.81			-104	%
Total expenses	$	48.94	$	92.43		$	(43.49	)		-47	%

        Production expenses.    Production expenses attributable to LOE increased 54% from $4.7 million in the first quarter of 2012 to $7.2 million in the first quarter of 2013 as a result of an increase in production volumes from wells drilled, which contributed $4.3 million of additional LOE, partially offset by a $1.98 decrease in the average per BOE rate, which reduced LOE by $1.8 million. The decrease in our average LOE per BOE rate was attributable to wells we successfully drilled and completed in 2012 and the first quarter of 2013 where we are experiencing economies of scale from our drilling program and from savings achieved through 2012 infrastructure projects that have resulted in material efficiencies in our field operations and, in particular, our disposal of water.

        Production expenses attributable to production, severance and ad valorem taxes increased 57% from $2.4 million in the first quarter of 2012 to $3.7 million in the first quarter of 2013 primarily due

63

to higher wellhead revenues, which exclude the effects of commodity derivative contracts, resulting from increased production from our drilling activity. As a percentage of wellhead revenues, production, severance, and ad valorem taxes decreased to 6.7% in the first quarter of 2013 as compared to 7.1% in the first quarter of 2012 primarily due to (1) an increase in oil revenues as a percentage of our total revenues, which are taxed at a lower rate than natural gas and NGLs, and (2) an increase in the number of wells brought on production in the first quarter of 2013 as compared to the first quarter of 2012 as we continue to utilize more efficient drilling rigs and reduce our time from spud to rig release. Wells brought on production during the first quarter of 2013 contributed to our production, but will not have ad valorem taxes assessed until 2014.

        DD&A expense.    DD&A expense increased 88% from $9.6 million in the first quarter of 2012 to $18.1 million in the first quarter of 2013 primarily due to an increase in production volumes and an increase in our asset base subject to amortization as a result of our drilling activity in 2012 and the first quarter of 2013.

        G&A expense.    G&A expense increased 29% from $2.6 million in the first quarter of 2012 to $3.3 million in the first quarter of 2013 primarily due to higher payroll and payroll-related costs as we continued to add employees in order to manage our growing asset base.

        Derivative fair value loss.    During the first quarter of 2013, we recorded a $6.8 million derivative fair value loss as compared to a loss of $22.7 million in the first quarter of 2012. The change in our derivative fair value loss was a result of additional oil swaps and basis differential swaps entered into during the first quarter of 2013 and the decrease in the future commodity price outlook during the first quarter of 2013 as compared to the first quarter of 2012, which favorably impacted the fair values of our commodity derivative contracts.

        Interest expense.    Interest expense increased 199% from $1.5 million in the first quarter of 2012 to $4.5 million in the first quarter of 2013 primarily due to higher weighted-average outstanding borrowings under our credit agreement and the issuance of $125 million of debt under our former second lien term loan in September 2012. Our weighted-average outstanding borrowings under our credit agreement were $272.0 million for the first quarter of 2013 as compared to $169.4 million for the first quarter of 2012. Our weighted-average interest rate for total indebtedness was 4.6% for the first quarter of 2013 as compared to 3.5% for the first quarter of 2012. Our weighted-average outstanding borrowings increased in the first quarter of 2013 as compared to the first quarter of 2012 in order to fund our higher level of development and exploration activities during 2012 and the first quarter of 2013.

        The following table provides the components of our interest expense for the periods indicated:

	Three months ended March 31,
						Increase / (Decrease)
	2013			2012
	(in thousands)
Credit agreement	$	1,923		$	1,359	$	564
Former second lien term loan agreement		2,350			—		2,350
Other		243			136		107
Less: interest capitalized		(42	)		—		(42	)
Total	$	4,474		$	1,495	$	2,979

64

Comparison of 2012 to 2011

        Revenues.    The following table provides the components of our revenues for the periods indicated, as well as each period's respective production volumes and average prices:

	Year ended December 31				Increase/(Decrease)
	2012		2011		$			%
Revenues (in thousands):
Oil	$	128,081	$	51,193	$	76,888			150	%
Natural gas		8,415		3,521		4,894			139	%
NGLs		20,615		10,967		9,648			88	%
Total revenues	$	157,111	$	65,681	$	91,430			139	%
Average realized prices:
Oil ($/Bbl) (excluding impact of cash settled derivatives)	$	87.90	$	92.08	$	(4.18	)		-5	%
Oil ($/Bbl) (after impact of cash settled derivatives)	$	87.45	$	91.27	$	(3.82	)		-4	%
Natural gas ($/Mcf)	$	2.66	$	3.46	$	(0.80	)		-23	%
NGLs ($/Bbl)	$	34.65	$	45.96	$	(11.31	)		-25	%
Combined ($/BOE) (excluding impact of cash settled derivatives)	$	60.91	$	68.13	$	(7.22	)		-11	%
Combined ($/BOE) (after impact of cash settled derivatives)	$	60.66	$	67.66	$	(7.00	)		-10	%
Total production volumes:
Oil (MBbls)		1,457		556		901			162	%
Natural gas (MMcf)		3,163		1,017		2,146			211	%
NGLs (MBbls)		595		239		356			149	%
Combined (MBOE)		2,579		964		1,615			168	%
Average daily production volumes:
Oil (Bbls/D)		3,981		1,523		2,458			161	%
Natural gas (Mcf/D)		8,641		2,786		5,855			210	%
NGLs (Bbls/D)		1,625		654		971			148	%
Combined (BOE/D)		7,047		2,641		4,406			167	%

        The following table shows the relationship between our average oil and natural gas realized prices as a percentage of average NYMEX prices for the periods indicated. Management uses the realized price to NYMEX margin analysis to analyze trends in our oil and natural gas revenues.

	Year ended December 31,
	2012			2011
Average realized oil price ($/Bbl)	$	87.90		$	92.08
Average NYMEX ($/Bbl)		94.19			95.11
Differential to NYMEX		(6.29	)		(3.03	)
Average realized oil price to NYMEX percentage		93	%		97	%
Average realized natural gas price ($/Mcf)	$	2.66		$	3.46
Average NYMEX ($/Mcf)		2.79			4.00
Differential to NYMEX		(0.13	)		(0.54	)
Average realized natural gas price to NYMEX percentage		95	%		87	%

        Our average realized oil price as a percentage of the average NYMEX price was 93% for 2012 as compared to 97% for 2011. All of our oil contracts include the Midland-Cushing differential, which widened in 2012 due to difficulty transporting oil production from the Permian Basin to the Gulf Coast refineries as a result of lack of logistics and infrastructure. However, several projects have recently been

65

implemented and several more are underway to ease these transportation difficulties which we believe could reduce our differentials to NYMEX in the future. Our average realized natural gas price as a percentage of the average NYMEX price improved to 95% for 2012 as compared to 87% for 2011 as a result of a full year of production from the properties acquired from Element, which have a higher percentage of their natural gas contracts weighted to an index that trades closer to the average NYMEX price than the natural gas contracts related to the properties acquired from SandRidge.

        Oil revenues increased 150% from $51.2 million in 2011 to $128.1 million in 2012 as a result of an increase in our oil production volumes of 901 MBbls, partially offset by a $4.18 per Bbl decrease in our average realized oil price. Our higher oil production increased oil revenues by $83.0 million and was primarily the result of a full year of production from our Element acquisition in October 2011, as well as our development program in the Permian Basin. The properties initially acquired from Element contributed approximately 113 MBbls ($10.1 million in revenue) of additional oil production in 2012 as compared to 2011 while our development program contributed approximately 788 MBbls ($72.9 million in revenue) of additional oil production. Our lower average realized oil price decreased oil revenues by $6.1 million and was primarily due to a lower average NYMEX price, which decreased from $95.11 per Bbl in 2011 to $94.19 per Bbl in 2012, and the widening of our oil differentials as previously discussed.

        Natural gas revenues increased 139% from $3.5 million in 2011 to $8.4 million in 2012 as a result of an increase in our natural gas production volumes of 2,146 MMcf, partially offset by a $0.80 per Mcf decrease in our average realized natural gas price. Our higher natural gas production increased natural gas revenues by $7.4 million and was primarily the result of a full year of production from our Element acquisition in October 2011, as well as our development program in the Permian Basin. The properties initially acquired from Element contributed approximately 299 MMcf ($0.8 million in revenue) of additional natural gas production in 2012 as compared to 2011 while our development program contributed approximately 1,847 MMcf ($6.6 million in revenue) of additional natural gas production. Our lower average realized natural gas price decreased natural gas revenues by $2.5 million and was primarily due to a lower average NYMEX price, which decreased from $4.00 per Mcf in 2011 to $2.79 per Mcf in 2012, partially offset by the improvement in our natural gas differentials as previously discussed.

        NGL revenues increased 88% from $11.0 million in 2011 to $20.6 million in 2012 as a result of an increase in our NGL production volumes of 356 MBbls, partially offset by an $11.31 per Bbl decrease in our average realized NGL price. Our higher NGL production increased NGL revenues by $16.4 million and was primarily the result of a full year of production from our Element acquisition in October 2011, as well as our development program in the Permian Basin. The properties initially acquired from Element contributed approximately 50 MBbls ($1.5 million in revenue) of additional NGL production in 2012 as compared to 2011 while our development program contributed approximately 306 MBbls ($14.9 million in revenue) of additional NGL production. Our lower average realized NGL price decreased NGL revenues by $6.7 million and was primarily due to increased supplies of NGLs from NGL-rich shales in the Permian Basin and other basins including the Eagle Ford and the Williston.

66

        Expenses.    The following table summarizes our expenses for the periods indicated:

	Year ended December 31,					Increase/(Decrease)
	2012			2011		$			%
Expenses (in thousands):
Production:
Lease operating	$	25,503		$	13,328	$	12,175			91	%
Production, severance and ad valorem taxes		10,438			4,727		5,711			121	%
Processing, gathering and overhead		84			60		24			40	%
Total production expenses		36,025			18,115		17,910			99	%
Other:
Depletion, depreciation and amortization		54,456			19,747		34,709			176	%
General and administrative		9,678			7,724		1,954			25	%
Acquisition costs		876			9,519		(8,643	)		-91	%
Derivative fair value loss (gain)		(9,293	)		7,959		(17,252	)		-217	%
Accretion		478			344		134			39	%
Total operating expenses		92,220			63,408		28,812			45	%
Interest		9,949			2,932		7,017			239	%
Income tax provision		1,928			470		1,458			310	%
Total expenses	$	104,097		$	66,810	$	37,287			56	%
Expenses (per BOE):
Production:
Lease operating	$	9.89		$	13.82	$	(3.93	)		-28	%
Production, severance and ad valorem taxes		4.05			4.90		(0.85	)		-17	%
Processing, gathering and overhead		0.03			0.06		(0.03	)		-50	%
Total production expenses		13.97			18.78		(4.81	)		-26	%
Other:
Depletion, depreciation and amortization		21.11			20.48		0.63			3	%
General and administrative		3.75			8.01		(4.26	)		-53	%
Acquisition costs		0.34			9.87		(9.53	)		-97	%
Derivative fair value loss (gain)		(3.60	)		8.26		(11.86	)		-144	%
Accretion		0.19			0.36		(0.17	)		-47	%
Total operating		35.76			65.76		(30.00	)		-46	%
Interest		3.86			3.04		0.82			27	%
Income tax provision		0.75			0.49		0.26			53	%
Total expenses	$	40.37		$	69.29	$	(28.92	)		-42	%

        Production expenses.    Production expenses attributable to LOE increased $12.2 million from $13.3 million in 2011 to $25.5 million in 2012 as a result of an increase in production volumes from drilled wells and a full year of LOE from our Element acquisition, which contributed $22.3 million of additional LOE, partially offset by a $3.93 decrease in the average per BOE rate, which reduced LOE by $10.1 million. The decrease in our average LOE per BOE rate was attributable to wells we successfully drilled and completed in 2012 where we are experiencing economies of scale from our drilling program and from savings achieved through 2012 infrastructure projects that have resulted in material efficiencies in our field operations and, in particular, our disposal of water.

        Production expenses attributable to production, severance and ad valorem taxes increased $5.7 million from $4.7 million in 2011 to $10.4 million in 2012 primarily due to higher wellhead

67

revenues, which exclude the effects of commodity derivative contracts, resulting from increased production from our acquisitions and drilling activity. As a percentage of wellhead revenues, production, severance and ad valorem taxes decreased to 6.6% in 2012 as compared to 7.2% in 2011 primarily due to an increase in oil revenues as a percentage of our total revenues, which are taxed at a lower rate than natural gas and NGLs, and because wells drilled in 2012 that contributed to our 2012 production will not have ad valorem taxes assessed until 2013.

        DD&A expense.    DD&A expense increased $34.7 million from $19.7 million in 2011 to $54.5 million in 2012 primarily due to a full year of production from the properties acquired in our Element acquisition and an increase in our asset base subject to amortization as a result of our 2012 drilling activity.

        G&A expense.    G&A expense increased $2.0 million from $7.7 million in 2011 to $9.7 million in 2012 primarily due to higher payroll and payroll-related costs as we added additional employees to manage our growing asset base.

        Acquisition costs.    Acquisition costs decreased $8.6 million from $9.5 million in 2011 to $0.9 million in 2012. We are party to a Transaction Fee Agreement, dated August 23, 2010, which requires us to pay a fee to Apollo equal to 2% of the total equity contributed to us, as defined in the agreement, in exchange for consulting and advisory services provided by Apollo. Upon the closing of the SandRidge acquisition in January 2011, we incurred a transaction fee payable to Apollo of $2.3 million. Upon the closing of the Element acquisition in October 2011, we incurred a transaction fee payable to Apollo of $4.3 million. In addition, we incurred other transaction costs associated with those significant acquisitions in 2011.

        Derivative fair value loss (gain).    During 2012, we recorded a $9.3 million derivative fair value gain as compared to an $8.0 million derivative fair value loss in 2011, the components of which were as follows:

	Year ended December 31,
						Increase/ (Decrease)
	2012			2011
	(in thousands)
Mark-to-market loss (gain)	$	(9,947	)	$	7,509	$	(17,456	)
Cash settlements		654			450		204
Total derivative fair value loss (gain)	$	(9,293	)	$	7,959	$	(17,252	)

        The change in our derivative fair value loss (gain) was a result of additional oil swaps entered into during 2012 and the decrease in the future commodity price outlook during 2012, which favorably impacted the fair values of our commodity derivative contracts.

        Interest expense.    Interest expense increased $7.0 million from $2.9 million in 2011 to $9.9 million in 2012 primarily due to higher weighted-average outstanding borrowings under our credit agreement and the issuance of $125 million of debt under our former second lien term loan in September 2012. Our weighted-average outstanding borrowings under credit agreements were $196.5 million for 2012 as compared to $78.4 million for 2011. Our weighted-average interest rate for total indebtedness was 4.3% for 2012 as compared to 3.8% for 2011. Our weighted-average outstanding borrowings increased in 2012 in order to fund the closing of the Element acquisition in October 2011 and our higher level of development and exploration activities during 2012.

68

        The following table provides the components of our interest expense for the periods indicated:

	Year ended December 31,
						Increase/ (Decrease)
	2012			2011
	(in thousands)
Credit agreements	$	5,932		$	2,387	$	3,545
Former second lien term loan		3,081			—		3,081
Other		1,155			545		610
Less: interest capitalized		(219	)		—		(219	)
Total	$	9,949		$	2,932	$	7,017

Capital Commitments, Capital Resources, and Liquidity

Capital commitments

        Our primary uses of cash are:

•

Development and exploration of oil and natural gas properties;

•

Acquisitions of oil and natural gas properties;

•

Funding of working capital; and

•

Contractual obligations.

        Development and exploration of oil and natural gas properties.    The following table summarizes our costs incurred related to development and exploration activities for the periods indicated:

	Three months ended March 31,				Year ended December 31,
	2013		2012		2012		2011
	(in thousands)
Development	$	49,238	$	24,370	$	201,174	$	71,403
Exploration		22,553		24,871		75,008		17,829
Total	$	71,791	$	49,241	$	276,182	$	89,232

        Our development capital primarily relates to drilling development and infill wells, workovers of existing wells and field related facilities. Our exploration expenditures primarily relate to drilling exploratory wells, seismic costs, delay rentals and geological and geophysical costs.

        Our development capital for the first quarter of 2013 yielded 19 gross (19 net) productive wells and no dry holes. Our exploration capital for the first quarter of 2013 yielded 16 gross (15 net) productive wells and no dry holes. The level of our development and exploration activities in the first quarter of 2013 were higher than in the first quarter of 2012 primarily due to our utilization of more efficient vertical drilling rigs that have significantly reduced the time from spud to rig release allowing us to drill more wells.

        Our development capital for 2012 yielded 102 gross (94 net) productive wells and two gross (two net) dry holes. Our exploration capital for 2012 yielded 29 gross (28 net) productive wells and no dry holes. The level of our development and exploration activities in 2012 were higher than in 2011 due to the increase in our operated drilling rigs from three to six upon the closing of the Element acquisition in October 2011.

        In 2013, we plan to invest approximately $317 million of development capital, including $15 million for infrastructure, leasing and capitalized workovers, and drill 162 gross (150 net) vertical Wolfberry

69

wells. We also plan to invest $33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells. Our 2013 development capital consists of:

•

$335 million of drilling and completion capital;

•

$5 million for infrastructure and other non-drilling capital projects as well as workovers of existing wells; and

•

$10 million for expanding our leasehold position.

        Acquisitions of oil and natural gas properties.    The following table summarizes our costs incurred related to oil and natural gas property acquisitions for the periods indicated:

	Year ended December 31,
	2012		2011
	(in thousands)
Acquisitions of proved properties	$	42,122	$	287,400
Acquisitions of unproved properties		38,908		130,273
Total	$	81,030	$	417,673

        We did not have any significant acquisitions during either the first quarter of 2013 or the first quarter of 2012.

        In the fourth quarter of 2012, we acquired certain oil and natural gas properties and related assets in the Permian Basin from three different sellers totaling for $74.9 million in cash.

        In January 2011, we acquired certain oil and natural gas properties and related assets in the Permian Basin from SandRidge for $156.0 million in cash. In October 2011, we acquired certain oil and natural gas properties and related assets in the Permian Basin from Element for $253.2 million in cash.

        Funding of working capital.    As of March 31, 2013 and December 31, 2012, our working capital deficit (defined as total current assets less total current liabilities) was $20.0 million and $22.2 million, respectively. Through 2013, we expect to continue to have working capital deficits primarily due to amounts accrued related to our extensive development activities. We expect our operating cash flows and availability under our credit agreement after application of the estimated net proceeds from this offering, as described under "Use of Proceeds," will be sufficient to fund our working capital needs, capital expenditures and other obligations for at least the next 12 months. We expect that our production volumes, commodity prices and differentials to NYMEX prices for our oil and natural gas production will be the largest variables affecting our working capital.

70

        Contractual obligations.    The following table provides our contractual obligations and commitments as of December 31, 2012:

	Payments Due by Period
Contractual Obligations and Commitments	Total		2013		2014 - 2015		2016 - 2017		Thereafter
	(in thousands)
Credit agreement1	$	265,370	$	6,468	$	12,936	$	245,966	$	—
Former second lien term loan1		170,848		9,375		18,750		142,723		—
Development commitments2		39,483		39,483		—		—		—
Operating leases and commitments3		1,787		471		938		378		—
Asset retirement obligations4		29,405		—		—		—		29,405
Total	$	506,893	$	55,797	$	32,624	$	389,067	$	29,405

¹

Includes principal and projected interest payments. Please read "—Liquidity" for additional information regarding our long-term debt.

²

Represents authorized purchases for work in process related to our drilling activities.

³

Represents operating leases that have non-cancelable lease terms in excess of one year.

⁴

Represents the undiscounted future plugging and abandonment expenses on oil and natural gas properties and related facilities disposal at the end of field life. Because these costs typically extend many years into the future, estimating these future costs requires management to make estimates and judgments that are subject to future revisions based upon numerous factors.

        The above table does not reflect our April 2013 senior notes offering and the application of the net proceeds therefrom.

        As of December 31, 2012, the fair value of our commodity derivative contracts, the ultimate settlement of which are unknown because they are subject to continuing market risk, was a net asset of $4.0 million. Please read "—Quantitative and Qualitative Disclosures about Market Risk" for additional information regarding our commodity derivative contracts.

        Off-balance sheet arrangements.    We have no investments in unconsolidated entities or persons that could materially affect our liquidity or the availability of capital resources. We do not have any off-balance sheet arrangements that have, or are reasonably likely to have, an effect on our financial condition or results of operations.

Capital resources

        The following table summarizes our cash flows for the periods indicated:

	Three months ended March 31,						Year ended December 31,
	2013			2012			2012			2011
	(in thousands)
Net cash provided by operating activities	$	30,397		$	20,723		$	95,302		$	18,872
Net cash used in investing activities		(90,560	)		(58,498	)		(347,259	)		(465,475	)
Net cash provided by financing activities		54,671			12,982			228,798			471,627
Net increase (decrease) in cash	$	(5,492	)	$	(24,793	)	$	(23,159	)	$	25,024

        Cash flows from operating activities.    Cash provided by operating activities increased $9.7 million from $20.7 million in the first quarter of 2012 to $30.4 million in the first quarter of 2013, primarily due to an increase in our production margin due to a 91% increase in production as a result of wells

71

drilled, partially offset by increased expenses as a result of having more producing wells in the first quarter of 2013 as compared to the first quarter of 2012.

        Cash provided by operating activities increased $76.4 million from $18.9 million in 2011 to $95.3 million in 2012, primarily due to an increase in our production margin as a result of a full year of production from our Element acquisition and wells drilled, partially offset by increased expenses as a result of our increased drilling activities in 2012 as compared to 2011.

        Cash flows used in investing activities.    Cash used in investing activities increased $32.1 million from $58.5 million in the first quarter of 2012 to $90.6 million in the first quarter of 2013, primarily due to a $24.5 million increase in amounts paid to develop oil and natural gas properties as we utilized more efficient vertical drilling rigs that have significantly reduced the time from spud to rig release allowing us to drill and complete more wells over the same time period.

        Cash used in investing activities decreased $118.2 million from $465.5 million in 2011 to $347.3 million in 2012, primarily due to a $334.2 million decrease in amounts paid to acquire oil and natural gas properties, which in 2011 included our SandRidge and Element acquisitions, partially offset by a $208.8 million increase in amounts paid to develop oil and natural gas properties as we utilized at least six rigs for the majority of 2012. In January 2011, we terminated certain oil puts that were in place at December 31, 2010 and received net proceeds of $7.6 million, which are included in cash used in investing activities for 2011.

        Cash flows from financing activities.    Our cash flows from financing activities consist primarily of net proceeds from and payments on long-term debt and contributions from partners. We periodically draw on our credit agreement and seek funding from partners to fund acquisitions and other capital commitments.

        During the first quarter of 2013, we received net cash of $54.7 million from financing activities, including net borrowings of $54.4 million under our credit agreement, which were used primarily to finance the first quarter of 2013 development activities. Net borrowings increased the outstanding borrowings under our credit agreement from $237 million at December 31, 2012 to $291.4 million at March 31, 2013.

        During the first quarter of 2012, we received net cash of $13.0 million from financing activities, consisting primarily of net borrowings under our credit agreement.

        During 2012, we received net cash of $228.8 million from financing activities, including $122.9 million of net proceeds from the issuance of our former second lien term loan, which were used to replace outstanding borrowings under our credit agreement, net borrowings of $67 million under our credit agreement and $40.2 million of partner contributions, which were used primarily to finance 2012 acquisitions. Net borrowings increased the outstanding borrowings under our credit agreements from $170 million at December 31, 2011 to $237 million at December 31, 2012.

        During 2011, we received net cash of $471.6 million from financing activities, including net borrowings of $170 million under our credit agreement and $304.0 million of partner contributions.

Liquidity

        Our primary sources of liquidity historically have been internally generated cash flows, the borrowing capacity under our credit agreement and partner contributions, including from our equity sponsor, the Apollo Funds. Since we operate a majority of our wells, we also have the ability to adjust our capital expenditures. We may use other sources of capital, including the issuance of debt or equity securities, to fund acquisitions or maintain our financial flexibility. We believe that our internally generated cash flows and expected future availability under our credit agreement after giving effect to the issuance of the securities offered hereby and the application of the estimated net proceeds from

72

this offering as described under "Use of Proceeds" will be sufficient to fund our operations and planned capital expenditures for at least the next 12 months. However, should commodity prices decline for an extended period of time or the capital/credit markets become constrained, the borrowing capacity under our credit agreement could be adversely affected. In the event of a reduction in the borrowing base under our credit agreement, we may be required to prepay some or all of our indebtedness, which would adversely affect our capital expenditure program. In addition, because wells funded in the next 12 months represent only a small percentage of our identified net drilling locations, we will be required to generate or raise multiples of this amount of capital to develop our entire inventory of identified drilling locations should we elect to do so.

        In 2013, we plan to invest approximately $350 million of development capital. The level of these and other future expenditures is largely discretionary, and the amount of funds devoted to any particular activity may increase or decrease significantly, depending on available opportunities, timing of projects and market conditions. We plan to finance our ongoing expenditures using internally generated cash flow and availability under our credit agreement.

        Internally generated cash flows.    Our internally generated cash flows, results of operations and financing for our operations are largely dependent on oil, natural gas and NGLs prices. During the first quarter of 2013, our average realized oil and NGLs prices decreased by 15% and 26%, respectively, as compared to the first quarter of 2012, while our average realized natural gas price increased by 21%. During 2012, our average realized oil, natural gas and NGLs prices decreased by 5%, 23% and 25%, respectively, as compared to 2011. Realized commodity prices fluctuate widely in response to changing market forces. If commodity prices decline or we experience a significant widening of our differentials to NYMEX prices, then our results of operations, cash flows from operations and borrowing base under our credit agreement may be adversely impacted. Prolonged periods of lower commodity prices or sustained wider differentials to NYMEX prices could cause us to not be in compliance with financial covenants under our credit agreement and thereby affect our liquidity. To offset reduced cash flows in a lower commodity price environment, we have established a portfolio of commodity derivative contracts consisting primarily of oil swaps that will provide stable cash flows on a portion of our oil production. As of March 31, 2013, our hedged oil volumes for 2013, 2014 and 2015 represent 99%, 96% and 21%, respectively, of our March 2013 oil production at weighted average prices of $94.18, $92.76 and $93.18, respectively. An increase in oil prices above the ceiling prices in our commodity derivative contracts limits cash inflows because we would be required to pay our counterparties for the difference between the market price for oil and the ceiling price of the commodity derivative contract resulting in a loss. Please read "—Quantitative and Qualitative Disclosures About Market Risk" for additional information regarding our commodity derivative contracts.

        Credit agreement.    We are a party to an amended and restated credit agreement dated March 19, 2013, which we refer to as our credit agreement, which matures on March 19, 2018. Our credit agreement provides for revolving credit loans to be made to us from time to time and letters of credit to be issued from time to time for the account of us or any of our restricted subsidiaries. The aggregate amount of the commitments of the lenders under our credit agreement is $1.0 billion. Availability under our credit agreement is subject to a borrowing base, which is redetermined semi-annually and upon requested special redeterminations.

        As of March 31, 2013, the borrowing base was $360 million and there were $291.4 million of outstanding borrowings, $68.6 million of borrowing capacity and no outstanding letters of credit under our credit agreement. In conjunction with the offering of our senior notes in April 2013 as discussed below, the borrowing base under our credit agreement was reduced to $267.5 million. We used a portion of the net proceeds from the offering of the senior notes to reduce the outstanding borrowings under our credit agreement. In May 2013, we amended our credit agreement to, among other things, increase the borrowing base to $320 million. As of July 12, 2013, there were $62.5 million of outstanding borrowings under our credit agreement.

73

        Obligations under our credit agreement are secured by a first-priority security interest in substantially all of our proved reserves and in the equity interests of our operating subsidiaries. In addition, obligations under our credit agreement are guaranteed by our operating subsidiaries.

        Loans under our credit agreement are subject to varying rates of interest based on (1) outstanding borrowings in relation to the borrowing base and (2) whether the loan is a Eurodollar loan or a base rate loan. Eurodollar loans under our credit agreement bear interest at the Eurodollar rate plus the applicable margin indicated in the following table, and base rate loans under our credit agreement bear interest at the base rate plus the applicable margin indicated in the following table. We also incur a quarterly commitment fee on the unused portion of our credit agreement indicated in the following table:

Ratio of Outstanding Borrowings to Borrowing Base	Unused Commitment Fee			Applicable Margin for Eurodollar Loans			Applicable Margin for Base Rate Loans
Less than or equal to .30 to 1		0.375	%		0.50	%		1.50	%
Greater than .30 to 1 but less than or equal to .60 to 1		0.375	%		0.75	%		1.75	%
Greater than .60 to 1 but less than or equal to .80 to 1		0.50	%		1.00	%		2.00	%
Greater than .80 to 1 but less than or equal to .90 to 1		0.50	%		1.25	%		2.25	%
Greater than .90 to 1		0.50	%		1.50	%		2.50	%

        The "Eurodollar rate" for any interest period (either one, two, three or six months, as selected by us) is the rate equal to the LIBOR for deposits in dollars for a similar interest period. The "Base Rate" is calculated as the highest of: (1) the annual rate of interest announced by Bank of America, N.A. as its "prime rate"; (2) the federal funds effective rate plus 0.5%; or (3) except during a "LIBOR Unavailability Period," the Eurodollar rate (for dollar deposits for a one-month term) for such day plus 1.0%.

        Any outstanding letters of credit reduce the availability under our credit agreement. Borrowings under our credit agreement may be repaid from time to time without penalty.

        Our credit agreement contains customary covenants including, among others, the following:

•

a prohibition against incurring debt, subject to permitted exceptions;

•

a restriction on creating liens on our assets and the assets of our operating subsidiaries, subject to permitted exceptions;

•

restrictions on merging and selling assets outside the ordinary course of business;

•

restrictions on use of proceeds, investments, transactions with affiliates or change of principal business;

•

a requirement that we maintain a ratio of consolidated total debt to EBITDAX (as defined in our credit agreement and as presented under "Summary Consolidated Financial, Reserve and Operating Data—Non-GAAP Financial Measures—Adjusted EBITDA") of not more than 4.75 to 1.0 (which ratio changes to 4.5 to 1.0 beginning with the quarter ended June 30, 2014); and

•

a provision limiting commodity derivative contracts to a volume not exceeding 85% of projected production from proved reserves for a period not exceeding 66 months from the date the commodity derivative contract is entered into.

        Our credit agreement contains customary events of default, including our failure to comply with our financial ratios described above, which would permit the lenders to accelerate the debt if not cured within applicable grace periods. If an event of default occurs and is continuing, lenders with a majority of the aggregate commitments may require Bank of America, N.A. to declare all amounts outstanding

74

under our credit agreement to be immediately due and payable, which would materially and adversely affect our financial condition and liquidity.

        Certain of the lenders underwriting our credit agreement are also counterparties to our commodity derivative contracts. Please read "—Quantitative and Qualitative Disclosures About Market Risk" for additional discussion.

        We expect to reduce outstanding borrowings under our credit agreement with a portion of the net proceeds from this offering.

        Senior notes.    In April 2013, we issued $500 million aggregate principal amount of 7³/8% senior notes due 2021. The net proceeds from the senior notes offering were used to repay a portion of the outstanding borrowings under our credit agreement, to repay in full and terminate our former second lien term loan, to make a $75 million distribution to Class A limited partners of Athlon Holdings LP and for general corporate purposes. The indenture governing the senior notes contains covenants, including, among other things, covenants that restrict our ability to:

•

make distributions, investments or other restricted payments if our fixed charge coverage ratio is less than 2.0 to 1.0;

•

incur additional indebtedness if our fixed charge coverage ratio would be less than 2.0 to 1.0; and

•

create liens, sell assets, consolidate or merge with any other person or engage in transactions with affiliates.

These covenants are subject to a number of important qualifications, limitations and exceptions. In addition, the indenture contains other customary terms, including certain events of default upon the occurrence of which the senior notes may be declared immediately due and payable.

        Under the indenture, starting on April 15, 2016, we will be able to redeem some or all of the senior notes at a premium that will decrease over time, plus accrued and unpaid interest to the date of redemption. Prior to April 15, 2016, we will be able, at our option, to redeem up to 35% of the aggregate principal amount of the senior notes at a price of 107.375% of the principal thereof, plus accrued and unpaid interest to the date of redemption, with an amount equal to the net proceeds from certain equity offerings. In addition, at our option, prior to April 15, 2016, we may redeem some or all of the senior notes at a redemption price equal to 100% of the principal amount of the senior notes, plus an "applicable premium," plus accrued and unpaid interest to the date of redemption. If a change of control occurs on or prior to July 15, 2014, we may redeem all, but not less than all, of the notes at 110% of the principal amount thereof plus accrued and unpaid interest to, but not including, the redemption date. Certain asset dispositions will be triggering events that may require us to repurchase all or any part of a noteholder's notes at a purchase price in cash equal to 101% of the principal amount thereof, plus accrued and unpaid interest, if any, to but excluding the date of repurchase. Interest on the senior notes is payable in cash semi-annually in arrears, commencing on October 15, 2013, through maturity.

        Capitalization.    At March 31, 2013, we had total assets of $916.5 million and total capitalization of $849.8 million, of which 51% was represented by equity and 49% by long-term debt. At December 31, 2012, we had total assets of $852.3 million and total capitalization of $782.9 million, of which 54% was represented by equity and 46% by long-term debt. The percentages of our capitalization represented by equity and long-term debt could vary in the future if debt or equity is used to finance capital projects or acquisitions.

75

Changes in Prices

        Our revenues, the value of our assets and our ability to obtain bank loans or additional capital on attractive terms are affected by changes in commodity prices, which can fluctuate significantly. The following table provides our average realized prices for the periods indicated:

	Three months ended March 31,				Year ended December 31,
	2013		2012		2012		2011
Average realized prices:
Oil ($/Bbl) (excluding impact of cash settled derivatives)	$	84.23	$	99.29	$	87.90	$	92.08
Oil ($/Bbl) (after impact of cash settled derivatives)		83.97		89.91		87.45		91.27
Natural gas ($/Mcf)		3.27		2.71		2.66		3.46
NGLs ($/Bbl)		31.34		42.48		34.65		45.96
Combined ($/BOE) (excluding impact of cash settled derivatives)		61.08		71.05		60.91		68.13
Combined ($/BOE) (after impact of cash settled derivatives)		60.92		65.50		60.66		67.66

        Increases in commodity prices may be accompanied by or result in: (1) increased development costs, as the demand for drilling operations increases; (2) increased severance taxes, as we are subject to higher severance taxes due to the increased value of hydrocarbons extracted from our wells; and (3) increased LOE, such as electricity costs, as the demand for services related to the operation of our wells increases. Decreases in commodity prices can have the opposite impact of those listed above and can result in an impairment charge to our oil and natural gas properties.

Critical Accounting Policies and Estimates

        Preparing financial statements in accordance with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures. Estimates and assumptions are based on information available prior to financial statements being issued. Due to the nature of these estimates, new facts or circumstances may arise resulting in revised estimates which differ from these estimates. Management considers an accounting estimate to be critical if it requires assumptions that have a high degree of subjectivity and judgment to account for outcomes that are highly uncertain and the impact of these estimates and assumptions is material to our consolidated results of operations or financial condition. Management has identified the following critical accounting policies and estimates.

Oil and Natural Gas Reserves

        Our estimates of proved reserves are based on the quantities of oil and natural gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible from a given date forward from known reservoirs under existing economic conditions and operating methods. Our independent petroleum engineers, CG&A, prepare a reserve and economic evaluation of all of our properties on a well-by-well basis. The accuracy of reserve estimates is a function of the:

•

quality and quantity of available data;

•

interpretation of that data;

•

accuracy of various mandated economic assumptions; and

•

judgment of the independent reserve engineer.

76

        Estimating reserves is subjective and actual quantities of oil and natural gas ultimately recovered can differ from estimates for many reasons. Future prices received for production and future production costs may vary, perhaps significantly, from the prices and costs assumed for purposes of calculating reserve estimates. We may not be able to develop proved reserves within the periods estimated. Actual production may not equal the estimated amounts used in the preparation of reserve projections. As these estimates change, calculated reserves change. Any change in reserves directly impacts our estimate of future cash flows from the property, the property's fair value and our DD&A rate.

        Our independent petroleum engineers, CG&A, estimate our proved reserves annually on December 31. This results in a new DD&A rate which we use for the preceding fourth quarter after adjusting for fourth quarter production. We internally estimate reserve additions and reclassifications of reserves from unproved to proved at the end of the first, second and third quarters for use in determining a DD&A rate for the respective quarter.

Method of Accounting for Oil and Natural Gas Properties

        We apply the provisions of the "Extractive Activities—Oil and Gas" topic of the Financial Accounting Standards Board's ("FASB") Accounting Standards Codification ("ASC"). We use the full cost method of accounting for our oil and natural gas properties. Under this method, costs directly associated with the acquisition, exploration and development of reserves are capitalized into a full cost pool. Capitalized costs are amortized using a unit-of-production method. Under this method, the provision for DD&A is computed at the end of each period by multiplying total production for the period by a depletion rate. The depletion rate is determined by dividing the total unamortized cost base plus future development costs by net equivalent proved reserves at the beginning of the period.

        Costs associated with unproved properties are excluded from the amortizable cost base until a determination has been made as to the existence of proved reserves. Unproved properties are reviewed at the end of each quarter to determine whether the costs incurred should be reclassified to the full cost pool and, thereby, subjected to amortization. The costs associated with unproved properties primarily consist of acquisition and leasehold costs as well as development costs for wells in progress for which a determination of the existence of proved reserves has not been made. These costs are transferred to the amortization base once a determination is made whether or not proved reserves can be assigned to the property, upon impairment of a lease or immediately upon determination that the well is unsuccessful. Costs of seismic data that cannot be directly associated to specific unproved properties are included in the full cost pool as incurred, otherwise, they are allocated to various unproved leaseholds and transferred to the amortization base with the associated leasehold costs on a specific project basis.

        Sales and abandonments of oil and natural gas properties being amortized are accounted for as adjustments to the full cost pool, with no gain or loss recognized, unless the adjustments would significantly alter the relationship between capitalized costs and proved reserves. A significant alteration would not ordinarily be expected to occur upon the sale of reserves involving less than 25% of the reserve quantities of a cost center.

        Natural gas volumes are converted to BOE at the rate of six Mcf of natural gas to one Bbl of oil. This convention is not an equivalent price basis and there may be a large difference in value between an equivalent volume of oil versus an equivalent volume of natural gas.

        We capitalize interest on expenditures made in connection with exploration and development projects that are not subject to current amortization. Interest is capitalized only for the period that activities are in progress to bring these projects to their intended use. Capitalized interest cannot exceed gross interest expense.

77

Impairment

        Unevaluated properties are assessed periodically, at least annually, for possible impairment. Properties are assessed on an individual basis or as a group if properties are individually insignificant. The assessment includes consideration of various factors, including, but not limited to: intent to drill, remaining lease term, geological and geophysical evaluations, drilling results and economic viability of development if proved reserves are assigned. During any period in which these factors indicate impairment, the cumulative drilling costs incurred to date for such property and all or a portion of the associated leasehold costs are transferred to the full cost pool and become subject to amortization.

        Under the full cost method of accounting, total capitalized costs of oil and natural gas properties, net of accumulated DD&A, less related deferred income taxes may not exceed an amount equal to PV-10 plus the lower of cost or fair value of unevaluated properties, plus estimated salvage value, less the related tax effects (the "ceiling limitation"). A ceiling limitation is calculated at the end of each quarter. If total capitalized costs, net of accumulated DD&A, less related deferred income taxes are greater than the ceiling limitation, a write-down or impairment of the full cost pool is required. A write-down of the carrying value of the full cost pool is a non-cash charge that reduces earnings and impacts equity in the period of occurrence and typically results in lower DD&A expense in future periods. Once incurred, a write-down cannot be reversed at a later date.

        The ceiling limitation calculation is prepared using the 12-month first-day-of-the-month oil and natural gas average prices, as adjusted for basis or location differentials, held constant over the life of the reserves ("net wellhead prices"). If applicable, these net wellhead prices would be further adjusted to include the effects of any fixed price arrangements for the sale of oil and natural gas. We use commodity derivative contracts to mitigate the risk against the volatility of oil and natural gas prices. Commodity derivative contracts that qualify and are designated as cash flow hedges are included in estimated future cash flows. We have not designated any of our commodity derivative contracts as cash flow hedges and therefore have excluded commodity derivative contracts in estimating future cash flows. The future cash outflows associated with future development or abandonment of wells are included in the computation of the discounted present value of future net revenues for purposes of the ceiling limitation calculation.

Asset Retirement Obligations

        We apply the provisions of the "Asset Retirement and Environmental Obligations" topic of the ASC. We have obligations as a result of lease agreements and enacted laws to remove our equipment and restore land at the end of production operations. These asset retirement obligations are primarily associated with plugging and abandoning wells and land remediation. At the time a well is drilled or acquired, we record a separate liability for the estimated fair value of our asset retirement obligations, with an offsetting increase to the related oil and natural gas asset representing asset retirement costs. The cost of the related oil and natural gas asset, including the asset retirement cost, is included in our full cost pool. The estimated fair value of an asset retirement obligation is the present value of the expected future cash outflows required to satisfy the asset retirement obligations discounted at our credit-adjusted, risk-free interest rate at the time the liability is incurred. Accretion expense is recognized over time as the discounted liability is accreted to its expected settlement value.

        Inherent to the present-value calculation are numerous estimates, assumptions and judgments, including, but not limited to: the ultimate settlement amounts, inflation factors, credit-adjusted risk-free rates, timing of settlement and changes in the legal, regulatory, environmental and political environments. To the extent future revisions to these assumptions affect the present value of the abandonment liability, we make corresponding adjustments to both the asset retirement obligation and the related oil and natural gas property asset balance. These revisions result in prospective changes to DD&A expense and accretion of the discounted abandonment liability.

78

Revenue Recognition

        Revenues from the sale of oil, natural gas and NGLs are recognized when they are realized or realizable and earned. Revenues are considered realized or realizable and earned when: (i) persuasive evidence of an arrangement exists; (ii) delivery has occurred or services have been rendered; (iii) the seller's price to the buyer is fixed or determinable; and (iv) collectability is reasonably assured. Because final settlement of our hydrocarbon sales can take up to two months, the estimated sales volumes and prices are estimated and accrued using information available at the time the revenue is recorded.

Derivatives

        We use various financial instruments for non-trading purposes to manage and reduce price volatility and other market risks associated with our oil production. These arrangements are structured to reduce our exposure to commodity price decreases, but they can also limit the benefit we might otherwise receive from commodity price increases. Our risk management activity is generally accomplished through over-the-counter commodity derivative contracts with large financial institutions.

        We apply the provisions of the "Derivatives and Hedging" topic of the ASC, which requires each derivative instrument to be recorded at fair value. If a derivative has not been designated as a hedge or does not otherwise qualify for hedge accounting, it must be adjusted to fair value through earnings. We elected not to designate our current portfolio of commodity derivative contracts as hedges. Therefore, changes in fair value of these derivative instruments are recognized in earnings.

        As required by GAAP, we utilize the most observable inputs available for the valuation technique used. The financial assets and liabilities are classified in their entirety based on the lowest level of input that is of significance to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of the financial assets and liabilities. Fair values of swaps are estimated using a combined income-based and market-based valuation methodology based upon forward commodity price curves obtained from independent pricing services. Our collars and puts are average value options. Settlement is determined by the average underlying price over a predetermined period of time. We use observable inputs in an option pricing valuation model to determine fair value such as: (1) current market and contractual prices for the underlying instruments; (2) quoted forward prices for oil and natural gas; (3) interest rates, such as a LIBOR curve for a term similar to the commodity derivative contract; and (4) appropriate volatilities.

        We adjust the valuations from the valuation model for nonperformance risk. For commodity derivative contracts which are in an asset position, we use the counterparty's credit default swap rating. For commodity derivative contracts which are in a liability position, we use the average credit default swap rating of our peer companies with similar credit profiles as currently we do not have our own credit default swap rating.

New Accounting Pronouncements

        In December 2011, the FASB issued ASU 2011-11, "Disclosures about Offsetting Assets and Liabilities" and in January 2013 issued ASU 2013-01, "Clarifying the Scope of Disclosures About Offsetting Assets and Liabilities." These ASUs created new disclosure requirements regarding the nature of an entity's rights of setoff and related arrangements associated with its derivative instruments, repurchase agreements and securities lending transactions. Certain disclosures of the amounts of certain instruments subject to enforceable master netting arrangements are required, irrespective of whether the entity has elected to offset those instruments in the balance sheet. These ASUs were effective retrospectively for annual reporting periods beginning on or after January 1, 2013. The adoption of these ASUs did not impact our financial condition, results of operations or liquidity.

79

Emerging Growth Company

        The JOBS Act permits an "emerging growth company" like us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies. We have elected to "opt out" of this provision and, as a result, we will comply with new or revised accounting standards as required when they are adopted. This decision to opt out of the extended transition period is irrevocable.

Quantitative and Qualitative Disclosures About Market Risk

        The primary objective of the following information is to provide quantitative and qualitative information about our potential exposure to market risks. The term "market risk" refers to the risk of loss arising from adverse changes in oil and natural gas prices and interest rates. The disclosures are not meant to be precise indicators of exposure, but rather indicators of potential exposure. This information provides indicators of how we view and manage our ongoing market risk exposures. We do not enter into market risk sensitive instruments for speculative trading purposes.

Derivative policy

        Due to the volatility of commodity prices, we enter into various derivative instruments to manage and reduce our exposure to price changes. We primarily utilize WTI crude oil swaps that establish a fixed price for the production covered by the swaps. We also have employed WTI crude oil options (including puts and collars) to further mitigate our commodity price risk. All contracts are settled with cash and do not require the delivery of physical volumes to satisfy settlement. While this strategy may result in lower net cash inflows in times of higher oil prices than we would otherwise have, had we not utilized these instruments, management believes that the resulting reduced volatility of cash flow resulting from use of derivatives is beneficial.

Counterparties

        At March 31, 2013, we had committed 10% or greater (in terms of fair market value) of our oil derivative contracts in asset positions to the following counterparties:

Counterparty	Fair Market Value of Oil Derivative Contracts Committed
	(in thousands)
BNP Paribas	$	1,824

        We do not require collateral from our counterparties for entering into financial instruments, so in order to mitigate the credit risk of financial instruments, we enter into master netting agreements with certain counterparties. The master netting agreement is a standardized, bilateral contract between a given counterparty and us. Instead of treating each financial transaction between the counterparty and us separately, the master netting agreement enables the counterparty and us to aggregate all financial trades and treat them as a single agreement. This arrangement is intended to benefit us in two ways: (1) default by a counterparty under one financial trade can trigger rights to terminate all financial trades with such counterparty; and (2) netting of settlement amounts reduces our credit exposure to a given counterparty in the event of close-out.

        The counterparties to our commodity derivative contracts are composed of six institutions, all of which are rated A- or better by Standard & Poor's and Baa2 or better by Moody's and five of which are lenders under our credit agreement.

80

Commodity price sensitivity

        Commodity prices are often subject to significant volatility due to many factors that are beyond our control, including but not limited to: prevailing economic conditions, supply and demand of hydrocarbons in the marketplace, actions by speculators and geopolitical events such as wars or natural disasters. We manage oil price risk with swaps, puts and collars. Swaps provide a fixed price for a notional amount of sales volumes. Puts provide a fixed floor price on a notional amount of sales volumes while allowing full price participation if the relevant index price closes above the floor price. Collars provide a floor price on a notional amount of sales volumes while allowing some additional price participation if the relevant index price closes above the floor price. This participation is limited by a ceiling price specified in the contract.

        The following table summarizes our open commodity derivative contracts as of March 31, 2013:

Period	Average Daily Floor Volume		Weighted- Average Floor Price		Average Daily Cap Volume		Weighted- Average Cap Price		Average Daily Swap Volume		Weighted- Average Swap Price		Asset (Liability) Fair Market Value
	(Bbl)		(per Bbl)		(Bbl)		(per Bbl)		(Bbl)		(per Bbl)		(in thousands)
2013		150	$	75.00		150	$	105.95		6,000	$	94.66	$	(3,474	)
2014		—		—		—		—		5,950		92.76		130
2015		—		—		—		—		1,300		93.18		1,782
													$	(1,562	)

        We are also a party to Midland-Cushing basis differential swaps for 5,000 Bbls/D at $1.20/Bbl for April through December 2013. At March 31, 2013, the fair value of these contracts was a liability of approximately $1.2 million.

        As stated above under "—Critical Accounting Policies and Estimates—Derivatives," we elected not to designate our derivative contracts as hedges and therefore changes in fair value of these instruments are recognized in earnings. As of March 31, 2013, the fair market value of our oil derivative contracts was a net liability of $2.7 million. Based on our open commodity derivative positions at March 31, 2013, a 10% increase in NYMEX prices for oil would increase our net commodity derivative liability by approximately $12.5 million, while a 10% decrease in NYMEX prices for oil would change our net commodity derivative liability to a net commodity derivative asset of approximately $10.1 million.

Interest rate sensitivity

        At March 31, 2013, we had outstanding debt of $416.4 million, all of which is subject to floating market rates of interest that are linked to the Eurodollar rate. At this level of floating rate debt, if the Eurodollar rate increased 10%, we would incur an additional $1.7 million of interest expense per year, and if the Eurodollar rate decreased 10%, we would incur $1.7 million less.

Internal Controls and Procedures

        We are not currently required to comply with the SEC's rules implementing Section 404 of the Sarbanes Oxley Act, and are therefore not required to make a formal assessment of the effectiveness of our internal control over financial reporting for that purpose. Upon becoming a public company, we will be required to comply with the SEC's rules implementing Section 302 of the Sarbanes-Oxley Act, which will require our management to certify financial and other information in our quarterly and annual reports and provide an annual management report on the effectiveness of our internal control over financial reporting. We will not be required to make our first assessment of our internal control over financial reporting under Section 404 until the year following our first annual report required to be filed with the SEC.

81

BUSINESS

General

        We are an independent exploration and production company focused on the acquisition, development and exploitation of unconventional oil and liquids-rich natural gas reserves in the Permian Basin. The Permian Basin spans portions of Texas and New Mexico and is composed of three primary sub-basins: the Delaware Basin, the Central Basin Platform and the Midland Basin. All of our properties are located in the Midland Basin. Our drilling activity is currently focused on the low-risk vertical development of stacked pay zones, including the Spraberry, Wolfcamp, Cline, Strawn, Atoka and Mississippian formations, which we refer to collectively as the Wolfberry play. We are a returns-focused organization and have targeted the Wolfberry play in the Midland Basin because of its favorable operating environment, consistent reservoir quality across multiple target horizons, long-lived reserve characteristics and high drilling success rates.

        We were founded in August 2010 by a group of former executives from Encore Acquisition Company following its acquisition by Denbury Resources, Inc. With an average of approximately 20 years of industry experience and over 10 years of history working together, our founding management has a proven track record of working as a team to acquire, develop and exploit oil and natural gas reserves in the Permian Basin as well as other resource plays in North America.

        Our acreage position was 124,925 gross (98,348 net) acres at May 31, 2013, which we group into three primary areas based on geographic location within the Midland Basin: Howard, Midland & Other and Glasscock. From the time we began operations in January 2011 through May 31, 2013, we have operated up to eight vertical drilling rigs simultaneously and have drilled 230 gross vertical Wolfberry wells with a 99% success rate across all three areas. This activity has allowed us to identify and de-risk our multi-year inventory of 4,902 gross (3,857 net) vertical drilling locations, while also identifying 1,079 gross (931 net) horizontal drilling locations in specific areas based on geophysical and technical data. As we continue to expand our vertical drilling activity to our undeveloped acreage, we expect to identify additional horizontal drilling locations.

        The following table summarizes our leasehold position and identified net drilling locations by primary geographic area as of May 31, 2013:

					Identified Drilling Locations1
					Vertical
	Acreage
					Net 40-acre2		Net 20-acre		Net Total		Drilling Inventory3 (years)		Net Horizontal4
	Gross		Net
Howard		69,661		51,556		1,140		1,291		2,431		37		403
Midland & Other		36,694		33,709		390		414		804		20		316
Glasscock		18,570		13,083		267		355		622		24		212
Total		124,925		98,348		1,797		2,060		3,857		30		931

¹

Represents locations specifically identified by management based on evaluation of applicable geologic, engineering and production data. The drilling locations on which we actually drill wells will ultimately depend on the availability of capital, regulatory approvals, oil and natural gas prices, costs, actual drilling results and other factors.

²

Includes 597 gross (560 net) locations booked as proved undeveloped locations in our proved reserve report as of December 31, 2012.

³

Based on our 2013 drilling program on a gross basis.

⁴

Includes horizontal drilling locations targeting Wolfcamp A, Wolfcamp B, Wolfcamp C, Cline and Mississippian intervals, which comprise 311 gross (272 net), 357 gross (317 net), 133 gross (125 net), 227 gross (193 net) and 51 gross (24 net) locations, respectively.

        Since our inception, we have completed two significant acquisitions and seven bolt-on acquisitions. At the time of each acquisition, based on internal engineering estimates, these properties collectively contributed approximately 3,600 BOE/D of production and approximately 43 MMBOE of proved reserves. We have significantly grown production and proved reserves on the properties we acquired through the successful execution of our low-risk vertical drilling program. From the time we began

82

operations in January 2011 through May 31, 2013, we have drilled 230 gross vertical Wolfberry wells on our properties with a 99% success rate and grown our production to 10,971 BOE/D for April 2013.

        In 2012, our development capital was approximately $276 million and we drilled a total of 133 gross (124 net) vertical Wolfberry wells. In 2013, we plan to invest $317 million of development capital, including $15 million for infrastructure, leasing and capitalized workovers, and drill 162 gross (150 net) vertical Wolfberry wells. We also plan to invest $33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells. We currently operate seven vertical drilling rigs on our properties and have operated between five and eight vertical drilling rigs since October 2011. We expect to take delivery of our first horizontal rig in the third quarter of 2013.

        Our estimate of proved reserves is prepared by CG&A, our independent petroleum engineers. As of December 31, 2012, we had 86 MMBOE of proved reserves, which were 58% oil, 22% NGLs and 20% natural gas and 30% proved developed. As of December 31, 2012, the PV-10 of our proved reserves was approximately $867 million, 59% of which was attributed to proved developed reserves. Our proved undeveloped reserves, or PUDs, are composed of 597 gross (560 net) potential vertical drilling locations. The following table provides information regarding our proved reserves and production by area as of December 31, 2012, except as otherwise noted below:

	Estimated Total Proved Reserves
														Average Net Daily Production3 (BOE/D)
	Oil (MMBbls)		NGLs (MMBbls)		Natural Gas (Bcf)		Total (MMBOE)		% Liquids1			PV-102 (in millions)				R/P Ratio (years)
Howard		20.2		7.3		36.3		33.5		82	%	$	365.4		4,160		22.1
Midland & Other		17.6		8.3		44.7		33.3		78	%		337.0		4,825		18.9
Glasscock		11.6		3.7		22.7		19.2		80	%		164.2		1,986		26.4
Total		49.4		19.3		103.7		86.0		80	%	$	866.6		10,971		21.5

¹

Includes both oil and NGLs.

²

PV-10 is a non-GAAP financial measure. Standarized Measure is the closest GAAP measure and our Standarized Measure was $850.9 million at December 31, 2012. For additional information about PV-10 and how it differs from the Standardized Measure, please read "Summary Consolidated Financial, Reserve and Operating Data—Non-GAAP Financial Measures."

³

During April 2013, inclusive of oil production of 6,345 Bbls/D in total.

Our Business Strategy

        We maintain a disciplined and analytical approach to investing in which we seek to direct capital in a manner that will maximize our rates of return as we develop our extensive resource base. Key elements of our strategy are:

•

Grow reserves, production and cash flow with our multi-year inventory of low-risk vertical drilling locations.  We have considerable experience managing large scale drilling programs and intend to efficiently develop our acreage position to maximize the value of our resource base. During 2012, we invested $276 million of development capital, drilled 133 gross (124 net) vertical Wolfberry wells and grew production by 4,204 BOE/D, or 93%, from 4,506 BOE/D in the fourth quarter of 2011 to 8,710 BOE/D in the fourth quarter of 2012. We also increased proved reserves by 40 MMBOE, or 86%, from 46 MMBOE at December 31, 2011 to 86 MMBOE at December 31, 2012. In 2013, we plan to invest approximately $317 million of development capital, including $15 million for infrastructure, leasing and capitalized workovers, and drill 162 gross (150 net) vertical Wolfberry wells. We also plan to invest $33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells in order to continue to grow our production and reserves.

•

Continuously improve capital and operating efficiency.  We continuously focus on optimizing the development of our resource base by seeking ways to maximize our recovery per well relative to the cost incurred and to minimize our operating cost per BOE produced. We apply an analytical approach to track and monitor the effectiveness of our drilling and completion techniques and

83

service providers. Additionally, we seek to build infrastructure that allows us to achieve economies of scale and reduce operating costs. Specifically, we have:

•

achieved first six-month average daily production volumes on our operated wells in Howard County of 85 BOE/D, which represents outperformance by 102% of average industry vertical well results since 2010 of 42 BOE/D in Howard County, based on data from the Texas Railroad Commission;

•

achieved first six-month average daily production volumes on our operated wells in Midland County of 106 BOE/D, which represents outperformance by 68% of average industry vertical well results since 2010 of 63 BOE/D in Midland County, based on data from the Texas Railroad Commission;

•

reduced average development costs per gross well in our Midland & Other area from $2.4 million in the first quarter of 2012 to $2.1 million in the fourth quarter of 2012, an improvement of 9%;

•

reduced average development costs per gross well in our Howard and Glasscock areas from $2.0 million in the first quarter of 2012 to $1.8 million in the fourth quarter of 2012, an improvement of 12%;

•

reduced the time from spud to rig release in our Howard and Glasscock areas from 16 days in the fourth quarter of 2011 to 8 days in the first quarter of 2013, an improvement of 50%; and

•

reduced LOE from $13.82 per BOE for 2011 to $9.89 per BOE for 2012, an improvement of 28%.

•

Balance capital allocation between our lower risk vertical drilling program and horizontal development opportunities.  We have historically focused on optimizing our vertical drilling and completion techniques across our acreage position. Vertical drilling involves less operational, financial and other risk than horizontal drilling, and we view our extensive delineation vertical development drilling program as "low risk" because the drilling locations were selected based on our drilling and production history in the area and well-established industry activity surrounding our acreage. Many operators in the Midland Basin are actively drilling horizontal wells, which is more expensive than drilling vertical Wolfberry wells but potentially recovers disproportionately more hydrocarbons per well. We monitor industry horizontal drilling activity and intend to utilize the knowledge gained from the increase in industry horizontal drilling in the Midland Basin. In the second half of 2013, we intend to supplement our vertical drilling with horizontal drilling in circumstances where we believe that horizontal drilling should offer competitive rates of return.

•

Evaluate and pursue oil-weighted acquisitions where we can add value through our technical expertise and knowledge of the basin.  We have significant experience acquiring and developing oil-weighted properties in the Permian Basin, and we expect to continue to selectively acquire additional properties in the Permian Basin that meet our rate-of-return objectives. Since our formation, we have completed two significant acquisitions and seven bolt-on acquisitions that have given us a unique and highly attractive acreage position, underpinned by strong baseline production and proved reserves. We believe our experience as a leading operator and our infrastructure footprint in the Permian Basin provide us with a competitive advantage in successfully executing and integrating acquisitions.

•

Maintain a disciplined, growth-oriented financial strategy.  We intend to fund our growth predominantly with internally generated cash flows while maintaining ample liquidity and access to capital markets. Substantially all of our lease terms allow us to allocate capital among projects in a manner that optimizes both costs and returns, resulting in a highly efficient drilling program. In addition, these terms allow us to adjust our capital spending depending on commodity prices and market conditions. We expect our operating cash flows, pro forma availability under our credit agreement and the net proceeds from this offering to be sufficient

84

to fund our capital expenditures and other obligations necessary to execute our business plan in 2013. Furthermore, we plan to hedge a significant portion of our expected production in order to stabilize our cash flows and maintain liquidity, allowing us to sustain a consistent drilling program, thereby preserving operational efficiencies that help us achieve our targeted rates of return.

Our Competitive Strengths

        We have a number of competitive strengths that we believe will help us to successfully execute our business strategies, including:

•

High caliber management team with substantial technical and operational expertise.  Our founding management team has an average of approximately 20 years of industry experience and over 10 years of history working together with a proven track record of value creation at publicly traded oil and natural gas companies, including Encore Acquisition Company, XTO Energy Inc., Apache Corporation and Anadarko Petroleum Corporation. As of May 31, 2013, we had 23 engineering, land and geosciences technical personnel in our Fort Worth and Midland offices, with personnel experienced in both conventional and unconventional drilling operations. We believe our management and technical team is one of our principal competitive strengths due to our team's industry experience and history of working together in the identification, execution and integration of acquisitions, cost efficient management of profitable, large scale drilling programs and disciplined allocation of capital focused on rates of return.

•

High quality asset base with significant oil exposure in the Midland Basin.  Our acreage is concentrated in Howard, Midland and Glasscock counties, which are some of the most active counties in the Midland Basin. Since 2010, more vertical wells have been drilled in each of Howard and Glasscock counties than any other county in the Midland Basin, and Midland County has been the fifth most active county, based on data from the Texas Railroad Commission. Of the 9,242 vertical wells drilled in the Midland Basin since 2010, 1,579 (17%) have been drilled in Howard County, 1,255 (14%) have been drilled in Glasscock County and 714 (8%) have been drilled in Midland county. Furthermore, we have intentionally focused on crude oil and liquids opportunities to benefit from the relative disparity between oil and natural gas prices on an energy-equivalent basis, which has persisted over the last several years and which we expect to continue in the future. Approximately 58% and 22% of our proved reserves were oil and NGLs, respectively, as of December 31, 2012.

•

De-risked Midland Basin acreage position with multi-year vertical drilling inventory.  Since our management team commenced our development program in January 2011 through May 31, 2013, we have drilled 230 gross operated vertical Wolfberry wells across our leasehold position with a 99% success rate. Based on our extensive analysis of geophysical and technical data gained as a result of our vertical drilling program and from offset operator activity, as of May 31, 2013, we have identified 2,298 gross (1,797 net) vertical drilling locations on 40-acre spacing and an additional 2,604 gross (2,060 net) vertical drilling locations on 20-acre spacing across our leasehold, all of which target crude oil and NGLs as the primary objectives across stacked pay zones. Together, these 4,902 gross (3,857 net) identified drilling locations represent over 30 years of drilling inventory based on our expected 2013 drilling program. We view this drilling inventory as de-risked because the drilling locations were selected based on our extensive delineation drilling and production history in the area and well-established industry activity surrounding our acreage.

•

Extensive horizontal development potential.  Operators have drilled hundreds of horizontal wells in the Wolfcamp, Cline and Mississippian formations in the Midland Basin, including numerous horizontal wells offsetting our acreage, and are continuing to accelerate horizontal drilling activity. Multiple Wolfcamp formations are prevalent across our entire leasehold position, and the Cline and Mississippian formations are present across portions of our leasehold position.

85

Based on vertical well control information from our operations and the operations of offset operators, we have initially identified 311 gross (272 net) horizontal drilling locations in the Wolfcamp A formation, 357 gross (317 net) horizontal drilling locations in the Wolfcamp B formation, 133 gross (125 net) horizontal drilling locations in the Wolfcamp C formation, 227 gross (193 net) horizontal drilling locations in the Cline formation and 51 gross (24 net) horizontal drilling locations in the Mississippian formation. In addition, the subsurface data we have collected from our vertical drilling program also supports the potential for additional horizontal drilling in other formations, including the Strawn and Atoka formations. As we continue to expand our vertical drilling activity to our undeveloped acreage, we expect to identify additional horizontal drilling locations. Our vertical drilling has been designed to preserve these future horizontal drilling opportunities and optimize hydrocarbon recovery rates on our acreage. Beginning in the second half of 2013, we intend to supplement our vertical drilling with horizontal drilling in circumstances where we believe that horizontal drilling should offer competitive rates of return.

•

Large, concentrated acreage position with significant operational control.  Substantially all of our acreage is located in three counties in the Midland Basin. Our properties are characterized by large, contiguous acreage blocks, which has enabled us to implement more efficient and cost-effective operating practices and to capture economies of scale, including our installation of centralized production and fluid handling facilities, lowering of rig mobilization times and procurement of better vendor services. We seek to operate our properties so that we can continue to implement these efficient operating practices and control all aspects of our development program, including the selection of specific drilling locations, the timing of the development and the drilling and completion techniques used to efficiently develop our significant resource base. As of December 31, 2012, we operated approximately 99% of our proved reserves.

Our Capital Restructuring Program

        In the first quarter of 2013, we commenced a plan to enhance our overall capital structure and liquidity, including the execution of our amended and restated credit agreement in March 2013 that extends the maturity date of our reserve based lending facility to 2018. On April 17, 2013, we issued $500 million of 7³/8% senior notes due 2021 and used most of the net proceeds from the offering to reduce the outstanding borrowings under our credit agreement and repay in full and terminate our former second lien term loan, thereby extending a large portion of our then-existing debt maturity to 2021. This offering represents a continuation of our plan, as we intend to apply the estimated proceeds of this offering to further reduce the outstanding borrowings under our credit agreement, provide additional liquidity for use in our drilling program and for general corporate purposes, including potential acquisitions.

2013 Capital Budget

        In 2013, we plan to invest $317 million of development capital, including $15 million for infrastructure, leasing and capitalized workovers, and drill 162 gross (150 net) vertical Wolfberry wells. We also plan to invest $33 million of development capital to drill 4 gross (4 net) horizontal Wolfcamp wells.

        In Howard, we plan to invest $155 million and drill 89 gross (82 net) wells. This includes 25 gross (23 net) PUD locations to be drilled through the Atoka/Mississippian formations at depths of approximately 9,900 feet. Our EURs per well for Howard PUD locations to be drilled through the Atoka/Mississippian formations average 141 MBOE as estimated by CG&A in our proved reserve report as of December 31, 2012. In addition, we plan to drill 64 gross (59 net) unproved locations through the Atoka/Mississippian formations.

        In Midland & Other, we plan to invest $95 million and drill 44 gross (42 net) wells. This includes 19 gross (19 net) PUD locations to be drilled through the Strawn/Atoka formations at depths of

86

approximately 11,300 feet. Our EURs per well for Midland & Other PUD locations to be drilled through the Strawn/Atoka formations average 208 MBOE as estimated by CG&A in our proved reserve report as of December 31, 2012. In addition, we plan to drill 25 gross (23 net) unproved locations through the Strawn/Atoka formations.

        In Glasscock, we plan to invest $52 million and drill 29 gross (26 net) wells. This includes 8 gross (7 net) PUD locations to be drilled through the Atoka formation at depths of approximately 10,150 feet. Our EURs per well for Glasscock PUD locations to be drilled through the Atoka formation average 118 MBOE as estimated by CG&A in our proved reserve report as of December 31, 2012. In addition, we plan to drill 21 gross (19 net) unproved locations through the Atoka formation.

Our Acquisition History

        A significant portion of our historical growth has been achieved through acquisitions. Since our formation in August 2010, we have completed two significant acquisitions and seven bolt-on acquisitions that have given us a unique and highly attractive acreage positions, underpinned by strong baseline production and proved reserves. Our significant acquisitions were the Element acquisition and the SandRidge acquisition. In the Element acquisition, we acquired certain oil and natural gas properties and related assets in the Permian Basin from Element Petroleum, LP in October 2011 for $253.2 million in cash. The Element properties included approximately 1,400 BOE/D of production and approximately 16.4 MMBOE of proved reserves at the time of acquisition based on internal reserve reports. In the SandRidge acquisition, we acquired certain oil and natural gas properties and related assets in the Permian Basin from SandRidge Exploration and Production, LLC in January 2011 for $156.0 million in cash. The SandRidge properties included approximately 1,600 BOE/D of production and approximately 19.1 MMBOE of proved reserves at the time of acquisition based on internal reserve reports. As a result of these acquisitions and our continued operations, the PV-10 of our proved reserves totaled approximately $866.6 million as of December 31, 2012.

Our Properties and Core Project Areas

        The following table summarizes certain operating information of our properties:

													Estimated Net Proved Reserves4
			Identified Drilling Locations1,2,3				2013 Budget3												Average Net Daily Production (BOE/D)5
	Net Acreage2						Gross Wells		Net Wells		Capex (in millions)				Average WI/NRI	% Developed
Area			Gross		Net								MMBOE
Howard		51,556		3,318		2,431		89		82	$	155		33.5	92%/71%		26	%		4,160
Midland & Other		33,709		887		804		44		42		95		33.3	93%/71%		35	%		4,825
Glasscock		13,083		697		622		29		26		52		19.2	95%/73%		27	%		1,986
Total		98,348		4,902		3,857		162		150	$	302		86.0	93%/72%		30	%		10,971

¹

Reflects locations specifically identified by management based on our evaluation of applicable geologic and engineering data. These identified potential drilling locations do not include any potential horizontal drilling locations. The drilling locations on which we actually drill wells will ultimately depend on the availability of capital, regulatory approvals, oil and natural gas prices, costs, actual drilling results and other factors.

²

As of May 31, 2013.

³

Excludes 4 gross (4 net) horizontal Wolfcamp wells and $33 million estimated capital to drill such wells.

⁴

As of December 31, 2012.

⁵

During April 2013, inclusive of oil production of 6,345 Bbls/D in total.

        The Permian Basin, which includes the Delaware Basin, the Central Basin Platform and the Midland Basin, is characterized by an extensive production history, mature infrastructure, long reserve life, multiple producing horizons and enhanced recovery potential. Based on data from the Texas Railroad Commission and the New Mexico Oil Conservation Division, current total production from the Permian Basin is approximately 2 MMBOE/D, of which 60% is oil. As of March 15, 2013, there were 478 total rigs operating in the Permian Basin, making it the most active basin in the United States. According to a report by the Energy Information Administration in August 2012, the Permian Basin is the largest oil producing basin in the United States and contains approximately 23% of the oil reserves in the United States. These reserves are found in multiple proven oil and liquids-rich natural gas producing stratigraphic horizons, which we refer to as stacked pay zones. These multiple stacked pay zones can accommodate multiple completions in a single wellbore with the potential for both vertical and horizontal drilling.

87

        Our properties are located within the Midland Basin in areas with approximately 3,000 feet to 4,000 feet of stacked pay zones. Our vertical drilling program is targeting the Spraberry, Wolfcamp, Cline, Strawn, Atoka and Mississippian formations. As we continue to develop our inventory of identified vertical drilling locations, we expect to significantly expand our horizontal inventory based upon the information we learn about the formations underlying our leaseholds. In 2012, drilling activity in the Midland Basin continued to show a trend toward horizontal development. Based on data from the Texas Railroad Commission, of the 3,555 wells drilled in the Midland Basin in 2012, 18% were horizontal compared to 10% in 2011. A significant portion of the vertical drilling activity in the Midland Basin targets the Wolfberry Play due to the low-risk nature of the resources available in the play. Companies currently active in the Midland Basin include Apache Corporation, Pioneer Natural Resources Company, EOG Resources, Inc., Concho Resources Inc., Energen Corporation, and Laredo Petroleum Holdings, Inc.

        Howard.    As of May 31, 2013, we had 69,661 gross (51,556 net) acres and an inventory of 1,577 gross (1,140 net) identified vertical drilling locations on 40-acre spacing and an additional 1,741 gross (1,291 net) identified vertical drilling locations on 20-acre spacing. We are currently operating four rigs in this area and intend to invest $155 million in 2013 and drill 89 gross (82 net) vertical Wolfberry wells. Based upon the 112 gross (105 net) wells we have drilled from the time we began operations in January 2011 through May 31, 2013, we have identified 511 gross (403 net) horizontal drilling locations consisting of 148 gross (121 net) Wolfcamp A locations, 174 gross (145 net) Wolfcamp B locations, 26 gross (25 net) Wolfcamp C locations, 112 gross (88 net) Cline locations and 51 gross (24 net) Mississippian locations.

        Midland & Other.    As of May 31, 2013, we had 36,694 gross (33,709 net) acres and an inventory of 424 gross (390 net) identified vertical drilling locations on 40-acre spacing and an additional 463 gross (414 net) identified vertical drilling locations on 20-acre spacing. We are currently operating two rigs in this area and intend to spend $95 million in 2013 and drill 44 gross (42 net) vertical Wolfberry wells. Based upon the 67 gross (67 net) wells we have drilled from the time we began operations in January 2011 through May 31, 2013, we have identified 336 gross (316 net) horizontal drilling locations consisting of 109 gross (102 net) Wolfcamp A locations, 125 gross (118 net) Wolfcamp B locations, 49 gross (48 net) Wolfcamp C locations and 53 gross (48 net) Cline locations.

        Glasscock.    As of May 31, 2013, we had 18,570 gross (13,083) net acres and an inventory of 297 gross (267 net) identified vertical drilling locations on 40-acre spacing and an additional 400 gross (355 net) identified vertical drilling locations on 20-acre spacing. We are currently operating one rig in this area and intend to spend $52 million in 2013 and drill 29 gross (26 net) vertical Wolfberry wells. Based upon the 51 gross (49 net) wells we have drilled from the time we began operations in January 2011 through May 31, 2013, we have identified 232 gross (212 net) horizontal drilling locations consisting of 54 gross (49 net) Wolfcamp A locations, 58 gross (53 net) Wolfcamp B locations, 58 gross (53 net) Wolfcamp C locations and 62 gross (57 net) Cline locations.

        Production Status.    In April 2013, net production was 329,118 BOE, or an average of 10,971 BOE/D, of which 80% was oil and NGLs and 20% was natural gas. During 2012, our average daily net production was 7,047 BOE/D, of which 80% was from oil and NGLs and 20% was from natural gas.

        Facilities.    Our oil and natural gas processing facilities are typical of those found in the Permian Basin. Our facilities located at well locations include field gathering systems, storage tank batteries, saltwater disposal systems, oil/gas/water separation equipment and pumping units. We own three saltwater disposal systems in our Howard County core areas with over 17,000 barrels of water per day ("bwpd") capacity and access to over 35 fresh water supply wells throughout our acreage, a saltwater disposal system in our Glasscock County core area with over 2,700 bwpd capacity and access to over 20 fresh water supply wells throughout our acreage, and three saltwater disposal systems in our Midland County core areas with over 14,000 bwpd capacity and access to over 20 fresh water supply wells

88

throughout our acreage. In addition, we have established pipeline infrastructures in each of these core areas to reduce our need for trucking services.

        Recent and Future Activity.    During 2012, 133 gross (124 net) wells were drilled on our Midland Basin acreage and our 2012 development capital was approximately $276 million. For 2012, our F&D costs were $8.42 per BOE. A total of 24 gross (21 net) wells were drilled on our Midland Basin acreage during 2011. As of May 31, 2013 we had 2,298 identified gross potential vertical drilling locations based on 40-acre spacing and an additional 2,604 identified gross potential vertical drilling locations based on 20-acre spacing. We currently expect to drill an estimated 162 gross (150 net) vertical Wolfberry wells and 4 gross (4 net) horizontal Wolfcamp wells on our acreage in 2013. The wells are expected to be drilled to approximately 9,900 feet to 11,300 feet at an estimated average completed gross well cost of approximately $1.80 million to $2.15 million per well. In this prospectus, we define identified potential drilling locations as locations specifically identified by management as an estimation of our multi-year drilling activities based on evaluation of applicable geologic and engineering data on 40-acre or 20-acre spacing as indicated. The availability of local infrastructure, drilling support assets and other factors as management may deem relevant, such as easement restrictions and state and local regulations, are considered in determining such locations. The drilling locations on which we actually drill wells will ultimately depend upon the availability of capital, regulatory approvals, seasonal restrictions, oil and natural gas prices, costs, actual drilling results and other factors.

Oil and Natural Gas Data

Proved Reserves

        Evaluation and Review of Proved Reserves.    Our historical proved reserve estimates were prepared by CG&A, our independent petroleum engineers. The technical persons responsible for preparing our proved reserve estimates meet the requirements with regard to qualifications, independence, objectivity and confidentiality set forth in the Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information promulgated by the Society of Petroleum Engineers. The third-party engineering firm does not own an interest in any of our properties, nor is it employed by us on a contingent basis. Copies of the independent petroleum engineering firm's proved reserve report as of December 31, 2012 is attached hereto as an exhibit.

        We maintain an internal staff of petroleum engineers and geoscience professionals who worked closely with our independent reserve engineers to ensure the integrity, accuracy and timeliness of the data used to calculate our proved reserves relating to our assets in the Permian Basin. Our internal technical team members meet with our independent reserve engineers periodically during the period covered by the proved reserve report to discuss the assumptions and methods used in the proved reserve estimation process. We provide historical information to the independent reserve engineers for our properties, such as ownership interest, oil and natural gas production, well test data, commodity prices and operating and development costs. Jennifer Palko, our Vice President—Business Development and Engineering, is primarily responsible for overseeing the preparation of all of our reserve estimates. Ms. Palko is a petroleum engineer with over 19 years of reservoir and operations experience and our geoscience staff has an average of approximately 14 years of industry experience per person.

        The preparation of our proved reserve estimates are completed in accordance with our internal control procedures. These procedures, which are intended to ensure reliability of reserve estimations, include the following:

•

review and verification of historical production data, which data is based on actual production as reported by us;

•

preparation of reserve estimates by Ms. Palko or under her direct supervision;

89

•

review by Ms. Palko of all of our reported proved reserves at the close of each quarter, including the review of all significant reserve changes and all new proved undeveloped reserves additions;

•

direct reporting responsibilities by Ms. Palko to our Chief Executive Officer; and

•

verification of property ownership by our land department.

        Estimation of Proved Reserves.    Under SEC rules, proved reserves are those quantities of oil and natural gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible—from a given date forward, from known reservoirs and under existing economic conditions, operating methods and government regulations—prior to the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic or probabilistic methods are used for the estimation. If deterministic methods are used, the SEC has defined reasonable certainty for proved reserves as a "high degree of confidence that the quantities will be recovered." All of our proved reserves as of December 31, 2012 were estimated using a deterministic method. The estimation of reserves involves two distinct determinations. The first determination results in the estimation of the quantities of recoverable oil and natural gas and the second determination results in the estimation of the uncertainty associated with those estimated quantities in accordance with the definitions established under SEC rules. The process of estimating the quantities of recoverable oil and natural gas reserves relies on the use of certain generally accepted analytical procedures. These analytical procedures fall into four broad categories or methods: (1) production performance-based methods; (2) material balance-based methods; (3) volumetric-based methods; and (4) analogy. These methods may be used singularly or in combination by the reserve evaluator in the process of estimating the quantities of reserves. Reserves for proved developed producing wells were estimated using production performance methods for the vast majority of properties. Certain new producing properties with very little production history were forecast using a combination of production performance and analogy to similar production, both of which are considered to provide a relatively high degree of accuracy. Non-producing reserve estimates, for developed and undeveloped properties, were forecast using either volumetric or analogy methods, or a combination of both. These methods provide a relatively high degree of accuracy for predicting proved developed non-producing and proved undeveloped reserves for our properties, due to the mature nature of the properties targeted for development and an abundance of subsurface control data.

        To estimate economically recoverable proved reserves and related future net cash flows, CG&A considered many factors and assumptions, including the use of reservoir parameters derived from geological, geophysical and engineering data which cannot be measured directly, economic criteria based on current costs and the SEC pricing requirements and forecasts of future production rates.

        Under SEC rules, reasonable certainty can be established using techniques that have been proven effective by actual production from projects in the same reservoir or an analogous reservoir or by other evidence using reliable technology that establishes reasonable certainty. Reliable technology is a grouping of one or more technologies (including computational methods) that has been field tested and has been demonstrated to provide reasonably certain results with consistency and repeatability in the formation being evaluated or in an analogous formation. To establish reasonable certainty with respect to our estimated proved reserves, the technologies and economic data used in the estimation of our proved reserves have been demonstrated to yield results with consistency and repeatability, and include production and well test data, downhole completion information, geologic data, electrical logs, radioactivity logs, core analyses, available seismic data and historical well cost and operating expense data.

        Summary of Oil and Natural Gas Reserves.    The following table presents our estimated net proved oil and natural gas reserves as of December 31, 2012 and 2011, based on the proved reserve reports prepared by CG&A, an independent petroleum engineering firm, and such proved reserve reports have

90

been prepared in accordance with the rules and regulations of the SEC. All of our proved reserves are located in the United States. Copies of the proved reserve reports as of December 31, 2012 and 2011 prepared by CG&A with respect to our properties are included as exhibits to the registration statement of which this prospectus forms a part. Our estimates of net proved reserves have not been filed with or included in reports to any federal authority or agency other than the SEC in connection with this offering.

	December 31,
	2012		2011
Proved developed reserves:
Oil (MBbls)		14,470		7,942
Natural gas (MMcf)		31,965		14,063
NGLs (MBbls)		5,900		3,211
Combined (MBOE)		25,698		13,496
Proved undeveloped reserves:
Oil (MBbls)		34,953		18,030
Natural gas (MMcf)		71,718		37,497
NGLs (MBbls)		13,375		8,338
Combined (MBOE)		60,281		32,618
Proved reserves:
Oil (MBbls)		49,423		25,972
Natural gas (MMcf)		103,683		51,560
NGLs (MBbls)		19,275		11,549
Combined (MBOE)		85,979		46,114

        Reserve engineering is and must be recognized as a subjective process of estimating volumes of economically recoverable oil and natural gas that cannot be measured in an exact manner. The accuracy of any reserve estimate is a function of the quality of available data and of engineering and geological interpretation. As a result, the estimates of different engineers often vary. In addition, the results of drilling, testing and production may justify revisions of such estimates. Accordingly, reserve estimates often differ from the quantities of oil and natural gas that are ultimately recovered. Estimates of economically recoverable oil and natural gas and of future net revenues are based on a number of variables and assumptions, all of which may vary from actual results, including geologic interpretation, prices and future production rates and costs. Please read "Risk Factors" appearing elsewhere in this prospectus.

        Additional information regarding our proved reserves can be found in the notes to our consolidated financial statements included elsewhere in this prospectus and the proved reserve reports as of December 31, 2012 and 2011 which are included as exhibits to the registration statement of which this prospectus forms a part.

Proved Undeveloped Reserves (PUDs)

        As of December 31, 2012, our proved undeveloped reserves were composed of 34,953 MBbls of oil, 71,718 MMcf of natural gas and 13,375 MBbls of NGLs, for a total of 60,281 MBOE. PUDs will be converted from undeveloped to developed as the applicable wells begin production.

        The following table summarizes our changes in PUDs during 2012 (in MBOE):

Balance, December 31, 2011	32,618
Purchases of minerals-in-place	6,393
Extensions and discoveries	35,810
Revisions of previous estimates1	(8,087	)
Transfers to proved developed	(6,453	)
Balance, December 31, 2012	60,281

¹

Revisions to previous estimates are comprised of 7,185 MBOE of PUDs that are not currently scheduled to be drilled within the next five years and 902 MBOE of negative net revisions due to the combination of price, cost and technical revisions.

91

        Costs incurred relating to the development of PUDs reflected in our 2011 proved reserve report were $135.3 million during 2012. In addition, we incurred costs of $65.9 million to develop locations that became classified as PUDs during 2012. Estimated future development costs relating to the development of PUDs are projected to be approximately $103.0 million in 2013, $163.2 million in 2014, $174.1 million in 2015, $315.9 million in 2016 and $289.7 million in 2017. As we continue to develop our properties and have more well production and completion data, we believe we will continue to realize cost savings and experience lower relative drilling and completion costs as we convert PUDs into proved developed reserves in upcoming years. All of our PUD drilling locations are scheduled to be drilled prior to the end of 2017.

        As of December 31, 2012, approximately 4% of our total proved reserves were classified as proved developed non-producing.

Oil and Natural Gas Production Prices and Production Costs

Production and Price History

        The following table sets forth information regarding net production of oil, natural gas and NGLs, and certain price and cost information for the periods indicated:

	Three months ended March 31,				Year ended December 31,
	2013		2012		2012		2011
Total production volumes:
Oil (MBbls)		542		276		1,457		556
Natural gas (MMcf)		1,030		534		3,163		1,017
NGLs (MBbls)		183		102		595		239
Combined (MBOE)		896		468		2,579		964
Average daily production volumes:
Oil (Bbls/D)		6,023		3,036		3,981		1,523
Natural gas (Mcf/D)		11,446		5,871		8,641		2,786
NGLs (Bbls/D)		2,028		1,125		1,625		654
Combined (BOE/D)		9,959		5,140		7,047		2,641
Average realized prices:
Oil ($/Bbl) (excluding impact of cash settled derivatives)	$	84.23	$	99.29	$	87.90	$	92.08
Oil ($/Bbl) (after impact of cash settled derivatives)		83.97		89.91		87.45		91.27
Natural gas ($/Mcf)		3.27		2.71		2.66		3.46
NGLs ($/Bbl)		31.34		42.48		34.65		45.96
Combined ($/BOE) (excluding impact of cash settled derivatives)		61.08		71.05		60.91		68.13
Combined ($/BOE) (after impact of cash settled derivatives)		60.92		65.50		60.66		67.66
Expenses (per BOE):
Lease operating	$	8.07	$	10.05	$	9.89	$	13.82
Production, severance and ad valorem taxes		4.12		5.03		4.05		4.90
Depletion, depreciation and amortization		20.14		20.55		21.11		20.48
General and administrative		3.73		5.55		3.75		8.01

92

Productive Wells

        As of December 31, 2012, we owned an average 92% working interest in 492 gross (454 net) productive wells. Productive wells consist of producing wells and wells capable of production, including oil wells awaiting connection to production facilities. Gross wells are the total number of producing wells in which we have an interest, and net wells are the sum of our fractional working interests owned in gross wells.

Developed and Undeveloped Acreage

        The following table sets forth information as of May 31, 2013 relating to our leasehold acreage. Developed acres are acres spaced or assigned to productive wells and does not include undrilled acreage held by production under the terms of the lease. Undeveloped acres are acres on which wells have not been drilled or completed to a point that would permit the production of commercial quantities of oil or natural gas, regardless of whether such acreage contains proved reserves. A gross acre is an acre in which a working interest is owned. The number of gross acres is the total number of acres in which a working interest is owned. A net acre is deemed to exist when the sum of the fractional ownership working interests in gross acres equals one. The number of net acres is the sum of the fractional working interests owned in gross acres expressed as whole numbers and fractions thereof.

	Developed Acreage				Undeveloped Acreage				Total Acreage
Area	Gross		Net		Gross		Net		Gross		Net
Howard		57,186		39,466		12,475		12,090		69,661		51,556
Midland & Other		10,768		9,504		25,926		24,205		36,694		33,709
Glasscock		10,435		5,051		8,135		8,032		18,570		13,083
Total		78,389		54,021		46,536		44,327		124,925		98,348

        Many of the leases comprising the undeveloped acreage set forth in the table above will expire at the end of their respective primary terms unless production from the leasehold acreage has been established prior to such date, in which event the lease will remain in effect until the cessation of production. As of May 31, 2013, we had leases representing 9,639 gross (7,653 net) acres scheduled to expire in 2013, 5,362 gross (4,257 net) acres scheduled to expire in 2014, 9,213 gross (7,363 net) acres scheduled to expire in 2015, 27,224 gross (21,049 net) acres scheduled to expire in 2016 and no net acres scheduled to expire in 2017. We have not attributed any PUD reserves to acreage whose expiration date precedes the scheduled date for PUD drilling.

Drilling Results

        The following table sets forth information with respect to the number of wells completed during the periods indicated. The information should not be considered indicative of future performance, nor should it be assumed that there is necessarily any correlation between the number of productive wells

93

drilled, quantities of reserves found or economic value. Productive wells are those that produce commercial quantities of hydrocarbons, whether or not they produce a reasonable rate of return.

	Year ended December 31,
	2012				2011
	Gross		Net		Gross		Net
Development Wells:
Productive		102		94		18		15
Dry holes		2		2		0		0
		104		96		18		15
Exploratory Wells:
Productive		29		28		5		5
Dry holes		0		0		1		1
		29		28		6		6
Total:
Productive		131		122		23		20
Dry holes		2		2		1		1
		133		124		24		21

        As of December 31, 2012, we had 25 gross (23 net) wells in the process of drilling, completing or dewatering or shut in awaiting infrastructure that are not reflected in the above table.

Operations

General

        As of December 31, 2012, we operated approximately 99% of our proved reserves. As operator, we design and manage the development of a well and supervise operation and maintenance activities on a day-to-day basis. Independent contractors engaged by us provide all the equipment and personnel associated with these activities. We employ petroleum engineers, geologists and land professionals who work to improve production rates, increase reserves and lower the cost of operating our oil and natural gas properties.

Marketing and Customers

        We market all of the oil and natural gas production from properties we operate for both our account and the account of the other working interest owners in these properties. We sell our natural gas production to purchasers at market price under contracts with terms ranging from month-to-month to over five years. All of our oil is also sold under various contracts with a month-to-month term.

        We normally sell production to a relatively small number of customers, as is customary in the exploration, development and production business. For 2012, three purchasers accounted for more than 10% of our revenues: Pecos Gathering & Marketing (43%); Occidental Petroleum Corporation (29%); and DCP Midstream (12%). For 2011, three purchasers accounted for more than 10% of our revenues: Occidental Petroleum Corporation (58%); DCP Midstream (13%); and Pecos Gathering & Marketing (13%). If a major customer decided to stop purchasing oil and natural gas from us, revenues could decline and our operating results and financial condition could be harmed. However, based on the current demand for oil and natural gas, and the availability of other purchasers, we believe that the loss of any one or all of our major purchasers would not have a material adverse effect on our financial condition and results of operations, as crude oil and natural gas are fungible products with well-established markets and numerous purchasers.

94

Transportation

        During the initial development of our fields, we consider all gathering and delivery infrastructure in the areas of our production. Our oil is transported from the wellhead to our tank batteries by our gathering systems. The oil is then transported by the purchaser by truck or pipeline to a tank farm, another pipeline or a refinery. Our natural gas is transported from the wellhead to the purchaser's meter and pipeline interconnection point through our gathering system.

Competition

        The oil and natural gas industry is intensely competitive, and we compete with other companies that have greater resources. Many of these companies not only explore for and produce oil and natural gas, but also carry on midstream and refining operations and market petroleum and other products on a regional, national or worldwide basis. These companies may be able to pay more for productive oil and natural gas properties and exploratory prospects or to define, evaluate, bid for and purchase a greater number of properties and prospects than our financial or human resources permit. In addition, these companies may have a greater ability to continue exploration activities during periods of low oil and natural gas market prices. Our larger or more integrated competitors may be able to absorb the burden of present and future federal, state, local and other laws and regulations more easily than we can, which would adversely affect our competitive position. Our ability to acquire additional properties and to discover reserves in the future will be dependent upon our ability to evaluate and select suitable properties and to consummate transactions in a highly competitive environment. In addition, because we have fewer financial and human resources than many companies in our industry, we may be at a disadvantage in bidding for exploratory prospects and producing reserves.

Title to Properties

        As is customary in the oil and natural gas industry, we initially conduct only a cursory review of the title to our properties. At such time as we determine to conduct drilling operations on those properties, we conduct a thorough title examination and perform curative work with respect to significant defects prior to commencement of drilling operations. To the extent title opinions or other investigations reflect title defects on those properties, we are typically responsible for curing any title defects at our expense. We generally will not commence drilling operations on a property until we have cured any material title defects on such property. We have obtained title opinions on substantially all of our properties and believe that we have satisfactory title to our properties in accordance with standards generally accepted in the oil and natural gas industry. Prior to completing an acquisition of oil and natural gas leases, we perform title reviews on the most significant leases and, depending on the materiality of properties, we may obtain a title opinion, obtain an updated title review or opinion or review previously obtained title opinions. Our oil and natural gas properties are subject to customary royalty and other interests, liens for current taxes and other burdens which we believe do not materially interfere with the use of or affect our carrying value of the properties.

Oil and Natural Gas Leases

        The typical oil and natural gas lease agreement covering our properties provides for the payment of royalties to the mineral owner for all oil and natural gas produced from any wells drilled on the leased premises. The lessor royalties and other leasehold burdens on our properties generally range from 20% to 30%, resulting in a net revenue interest to us of 70% to 80%.

95

Regulation

Environmental Matters and Regulation

        Our oil and natural gas exploration, development and production operations are subject to stringent laws and regulations governing the discharge of materials into the environment or otherwise relating to environmental protection. Numerous governmental agencies, such as the EPA, issue regulations which often require difficult and costly compliance measures that carry substantial administrative, civil and criminal penalties and may result in injunctive obligations for non-compliance. These laws and regulations may require the acquisition of a permit before drilling commences, restrict the types, quantities and concentrations of various substances that can be released into the environment in connection with drilling and production activities, limit or prohibit construction or drilling activities on certain lands lying within wilderness, wetlands, ecologically sensitive and other protected areas, require action to prevent or remediate pollution from current or former operations, such as plugging abandoned wells or closing pits, result in the suspension or revocation of necessary permits, licenses and authorizations, require that additional pollution controls be installed and impose substantial liabilities for pollution resulting from our operations or relate to our owned or operated facilities. The strict and joint and several liability nature of such laws and regulations could impose liability upon us regardless of fault. Moreover, it is not uncommon for neighboring landowners and other third parties to file claims for personal injury and property damage allegedly caused by the release of hazardous substances, hydrocarbons or other waste products into the environment. Changes in environmental laws and regulations occur frequently, and any changes that result in more stringent and costly pollution control or waste handling, storage, transport, disposal or cleanup requirements could materially adversely affect our results of operations and financial condition, as well as the oil and natural gas industry in general. Our management believes that we are in substantial compliance with applicable environmental laws and regulations and we have not experienced any material adverse effect from compliance with these environmental requirements. This trend, however, may not continue in the future.

        Waste Handling.    The Resource Conservation and Recovery Act, as amended, ("RCRA") and comparable state statutes and regulations promulgated thereunder, affect oil and natural gas exploration, development and production activities by imposing requirements regarding the generation, transportation, treatment, storage, disposal and cleanup of hazardous and non-hazardous wastes. With federal approval, the individual states administer some or all of the provisions of RCRA, sometimes in conjunction with their own, more stringent requirements. Although most wastes associated with the exploration, development and production of crude oil and natural gas are exempt from regulation as hazardous wastes under RCRA, such wastes may constitute "solid wastes" that are subject to the less stringent requirements of non-hazardous waste provisions. However, we cannot assure you that the EPA or state or local governments will not adopt more stringent requirements for the handling of non-hazardous wastes or categorize some non-hazardous wastes as hazardous for future regulation. Indeed, legislation has been proposed from time to time in Congress to re-categorize certain oil and natural gas exploration, development and production wastes as "hazardous wastes." Any such changes in the laws and regulations could have a material adverse effect on our capital expenditures and operating expenses.

        Administrative, civil and criminal penalties can be imposed for failure to comply with waste handling requirements. We believe that we are in substantial compliance with applicable requirements related to waste handling, and that we hold all necessary and up-to-date permits, registrations and other authorizations to the extent that our operations require them under such laws and regulations. Although we do not believe the current costs of managing our wastes, as presently classified, to be significant, any legislative or regulatory reclassification of oil and natural gas exploration and production wastes could increase our costs to manage and dispose of such wastes.

96

        Remediation of Hazardous Substances.    The Comprehensive Environmental Response, Compensation and Liability Act, as amended, ("CERCLA") also known as the "Superfund" law, and analogous state laws, generally imposes strict and joint and several liability, without regard to fault or legality of the original conduct, on classes of persons who are considered to be responsible for the release of a "hazardous substance" into the environment. These persons include the current owner or operator of a contaminated facility, a former owner or operator of the facility at the time of contamination, and those persons that disposed or arranged for the disposal of the hazardous substance at the facility. Under CERCLA and comparable state statutes, persons deemed "responsible parties" may be subject to strict and joint and several liability for the costs of removing or remediating previously disposed wastes (including wastes disposed of or released by prior owners or operators) or property contamination (including groundwater contamination), for damages to natural resources and for the costs of certain health studies. In addition, it is not uncommon for neighboring landowners and other third parties to file claims for personal injury and property damage allegedly caused by the hazardous substances released into the environment. In the course of our operations, we use materials that, if released, would be subject to CERCLA and comparable state statutes. Therefore, governmental agencies or third parties may seek to hold us responsible under CERCLA and comparable state statutes for all or part of the costs to clean up sites at which such "hazardous substances" have been released.

        Water Discharges.    The Federal Water Pollution Control Act of 1972, as amended, also known as the Clean Water Act (the "CWA"), the SDWA, the Oil Pollution Act (the "OPA") and analogous state laws and regulations promulgated thereunder impose restrictions and strict controls regarding the unauthorized discharge of pollutants, including produced waters and other gas and oil wastes, into navigable waters of the United States, as well as state waters. The discharge of pollutants into regulated waters is prohibited, except in accordance with the terms of a permit issued by the EPA or the state. The CWA and regulations implemented thereunder also prohibit the discharge of dredge and fill material into regulated waters, including jurisdictional wetlands, unless authorized by an appropriately issued permit. Spill prevention, control and countermeasure plan requirements under federal law require appropriate containment berms and similar structures to help prevent the contamination of navigable waters in the event of a petroleum hydrocarbon tank spill, rupture or leak. These laws and regulations also prohibit certain activity in wetlands unless authorized by a permit issued by the U.S. Army Corps of Engineers. The EPA has also adopted regulations requiring certain oil and natural gas exploration and production facilities to obtain individual permits or coverage under general permits for storm water discharges. In addition, on October 20, 2011, the EPA announced a schedule to develop pre-treatment standards for wastewater discharges produced by natural gas extraction from underground coalbed and shale formations. The EPA stated that it will gather data, consult with stakeholders, including ongoing consultation with industry, and solicit public comment on a proposed rule for coalbed methane in 2013 and a proposed rule for shale gas in 2014. Costs may be associated with the treatment of wastewater or developing and implementing storm water pollution prevention plans, as well as for monitoring and sampling the storm water runoff from certain of our facilities. Some states also maintain groundwater protection programs that require permits for discharges or operations that may impact groundwater conditions.

        The OPA is the primary federal law for oil spill liability. The OPA contains numerous requirements relating to the prevention of and response to petroleum releases into waters of the United States, including the requirement that operators of offshore facilities and certain onshore facilities near or crossing waterways must develop and maintain facility response contingency plans and maintain certain significant levels of financial assurance to cover potential environmental cleanup and restoration costs. The OPA subjects owners of facilities to strict, joint and several liability for all containment and cleanup costs and certain other damages arising from a release, including, but not limited to, the costs of responding to a release of oil to surface waters.

97

        Noncompliance with the CWA or the OPA may result in substantial administrative, civil and criminal penalties, as well as injunctive obligations. We believe we are in material compliance with the requirements of each of these laws.

        Air Emissions.    The CAA and comparable state laws and regulations regulate emissions of various air pollutants through the issuance of permits and the imposition of other requirements. The EPA has developed, and continues to develop, stringent regulations governing emissions of air pollutants at specified sources. New facilities may be required to obtain permits before work can begin, and existing facilities may be required to obtain additional permits and incur capital costs in order to remain in compliance. For example, on April 17, 2012, the EPA approved final regulations under the CAA that establish new emission controls for oil and natural gas production and processing operations, which regulations are discussed in more detail in "—Regulation of Hydraulic Fracturing." These laws and regulations may increase the costs of compliance for some facilities we own or operate, and federal and state regulatory agencies can impose administrative, civil and criminal penalties for non-compliance with air permits or other requirements of the CAA and associated state laws and regulations. We believe that we are in substantial compliance with all applicable air emissions regulations and that we hold all necessary and valid construction and operating permits for our operations. Obtaining or renewing permits has the potential to delay the development of oil and natural gas projects.

        Climate Change.    Many nations have agreed to limit emissions of GHGs pursuant to the Kyoto Protocol. Methane, a primary component of natural gas, and carbon dioxide, a byproduct of the burning of oil, natural gas and refined petroleum products, are GHGs regulated by the Kyoto Protocol. Although the United States is not participating in the Kyoto Protocol at this time, several states or geographic regions have adopted legislation and regulations to reduce emissions of GHGs. The EPA has adopted two sets of related rules, one of which purports to regulate emissions of GHGs from motor vehicles and the other of which regulates emissions of GHGs from certain large stationary sources of emissions such as power plants or industrial facilities. The EPA finalized the motor vehicle rule in April 2010 and it became effective January 2011. The EPA adopted the stationary source rule, also known as the "Tailoring Rule," in May 2010, and it also became effective January 2011. Additionally, in September 2009, the EPA issued a final rule requiring the reporting of GHG emissions from specified large GHG emission sources in the U.S., including NGLs fractionators and local natural gas/distribution companies, beginning in 2011 for emissions occurring in 2010. In November 2010, the EPA expanded its existing GHG reporting rule to include onshore and offshore oil and natural gas production and onshore processing, transmission, storage and distribution facilities, which may include certain of our facilities, beginning in 2012 for emissions occurring in 2011. In addition, the EPA has continued to adopt GHG regulations of other industries, such as the March 2012 proposed GHG rule restricting future development of coal-fired power plants. As a result of this continued regulatory focus, future GHG regulations of the oil and natural gas industry remain a possibility.

        In addition, the U.S. Congress has from time to time considered adopting legislation to reduce emissions of GHGs and almost one-half of the states have already taken legal measures to reduce emissions of GHGs primarily through the planned development of GHG emission inventories and/or regional GHG cap and trade programs. Although the U.S. Congress has not adopted such legislation at this time, it may do so in the future and many states continue to pursue regulations to reduce greenhouse gas emissions. Most of these cap and trade programs work by requiring major sources of emissions, such as electric power plants or major producers of fuels, such as refineries and natural gas processing plants, to acquire and surrender emission allowances that correspond to their annual emissions of GHGs. The number of allowances available for purchase is reduced each year until the overall GHG emission reduction goal is achieved. As the number of GHG emission allowances declines each year, the cost or value of such allowances is expected to escalate significantly.

        Restrictions on GHG emissions that may be imposed in various states could adversely affect the oil and natural gas industry. While we are subject to certain federal GHG monitoring and reporting

98

requirements, our operations are not adversely impacted by existing federal, state and local climate change initiatives and, at this time, it is not possible to accurately estimate how future laws or regulations addressing GHG emissions would impact our business.

Regulation of Hydraulic Fracturing

        Hydraulic fracturing is an important common practice that is used to stimulate production of hydrocarbons, particularly natural gas, from tight formations, including shales. The process involves the injection of water, sand and chemicals under pressure into formations to fracture the surrounding rock and stimulate production. The SDWA regulates the underground injection of substances through the UIC program. Hydraulic fracturing generally is exempt from regulation under the UIC program, and the hydraulic fracturing process is typically regulated by state oil and natural gas commissions. The EPA, however, has recently taken the position that hydraulic fracturing with fluids containing diesel fuel is subject to regulation under the UIC program, specifically as "Class II" UIC wells. At the same time, the EPA has commenced a study of the potential environmental impacts of hydraulic fracturing activities, and a committee of the U.S. House of Representatives is also conducting an investigation of hydraulic fracturing practices. Moreover, the EPA commenced a study regarding the environmental effects of hydraulic fracturing activities. The EPA issued a Progress Report in December 2012 and a final draft is anticipated by 2014 for peer review and public comment. As part of these studies, both the EPA and the House committee have requested that certain companies provide them with information concerning the chemicals used in the hydraulic fracturing process. These studies, depending on their results, could spur initiatives to regulate hydraulic fracturing under the SDWA or otherwise. Further, on October 20, 2011, the EPA announced its intention to propose federal Clean Water Act regulations by 2014 governing wastewater discharges from hydraulic fracturing and certain other natural gas operations. Legislation to amend the SDWA to repeal the exemption for hydraulic fracturing from the definition of "underground injection" and require federal permitting and regulatory control of hydraulic fracturing, as well as legislative proposals to require disclosure of the chemical constituents of the fluids used in the fracturing process, were proposed in recent sessions of Congress. The U.S. Congress continues to consider legislation to amend the SDWA.

        Federal agencies are also considering additional regulation of hydraulic fracturing. On October 20, 2011, the EPA announced its intention to propose federal Clean Water Act regulations by 2014 governing wastewater discharges from hydraulic fracturing and certain other natural gas operations.

        On August 16, 2012, the EPA published final regulations under the CAA that establish new air emission controls for oil and natural gas production and natural gas processing operations. Specifically, the EPA's rule package includes New Source Performance Standards to address emissions of sulfur dioxide and VOCs and a separate set of emission standards to address hazardous air pollutants frequently associated with oil and natural gas production and processing activities. The final rule includes a 95% reduction in VOCs emitted by requiring the use of reduced emission completions or "green completions" on all hydraulically-fractured wells constructed or refractured after January 1, 2015. The rules also establish specific new requirements regarding emissions from compressors, controllers, dehydrators, storage tanks and other production equipment. The EPA received numerous requests for reconsideration of these rules from both industry and the environmental community, and court challenges to the rules were also filed. The EPA intends to issue revised rules in 2013 that are likely responsive to some of these requests. For example, on April 12, 2013, the EPA published a proposed amendment extending compliance dates for certain storage vessels. The final revised rules could require modifications to our operations or increase our capital and operating costs without being offset by increased product capture. At this point, we cannot predict the final regulatory requirements or the cost to comply with such requirements with any certainty. The U.S. Department of the Interior has also announced its intention to propose a new rule regulating hydraulic fracturing activities on federal lands, including requirements for disclosure, wellbore integrity and handling of flowback water.

99

        Several states, including Texas have adopted, or are considering adopting, regulations that could restrict or prohibit hydraulic fracturing in certain circumstances and/or require the disclosure of the composition of hydraulic fracturing fluids. In June 2011, Texas enacted a law requiring oil and natural gas operators to publicly disclose the chemicals used in the hydraulic fracturing process, effective as of September 1, 2011. The Texas Railroad Commission has adopted rules and regulations implementing this legislation that will apply to all wells for which the Texas Railroad Commission issues an initial drilling permit on or after February 1, 2012. The new law requires that the well operator disclose the list of chemical ingredients subject to the requirements of the OSHA for disclosure on an internet website and also file the list of chemicals with the Texas Railroad Commission with the well completion report. The total volume of water used to hydraulically fracture a well must also be disclosed to the public and filed with the Texas Railroad Commission.

        There has been increasing public controversy regarding hydraulic fracturing with regard to use of fracturing fluids, impacts on drinking water supplies, use of waters and the potential for impacts to surface water, groundwater and the environment generally. A number of lawsuits and enforcement actions have been initiated across the country implicating hydraulic fracturing practices. If new laws or regulations that significantly restrict hydraulic fracturing are adopted, such laws could make it more difficult or costly for us to perform fracturing to stimulate production from tight formations as well as make it easier for third parties opposing the hydraulic fracturing process to initiate legal proceedings based on allegations that specific chemicals used in the fracturing process could adversely affect groundwater. In addition, if hydraulic fracturing is further regulated at the federal or state level, our fracturing activities could become subject to additional permitting and financial assurance requirements, more stringent construction specifications, increased monitoring, reporting and recordkeeping obligations, plugging and abandonment requirements and also to attendant permitting delays and potential increases in costs. Such legislative changes could cause us to incur substantial compliance costs, and compliance or the consequences of any failure to comply by us could have a material adverse effect on our financial condition and results of operations. At this time, it is not possible to estimate the impact on our business of newly enacted or potential federal or state legislation governing hydraulic fracturing.

Other Regulation of the Oil and Natural Gas Industry

        The oil and natural gas industry is extensively regulated by numerous federal, state and local authorities. Legislation affecting the oil and natural gas industry is under constant review for amendment or expansion, frequently increasing the regulatory burden. Also, numerous departments and agencies, both federal and state, are authorized by statute to issue rules and regulations that are binding on the oil and natural gas industry and its individual members, some of which carry substantial penalties for failure to comply. Although the regulatory burden on the oil and natural gas industry increases our cost of doing business and, consequently, affects our profitability, these burdens generally do not affect us any differently or to any greater or lesser extent than they affect other companies in the industry with similar types, quantities and locations of production.

        The availability, terms and cost of transportation significantly affect sales of oil and natural gas. The interstate transportation and sale for resale of oil and natural gas is subject to federal regulation, including regulation of the terms, conditions and rates for interstate transportation, storage and various other matters, primarily by FERC. Federal and state regulations govern the price and terms for access to oil and natural gas pipeline transportation. FERC's regulations for interstate oil and natural gas transmission in some circumstances may also affect the intrastate transportation of oil and natural gas.

        Although oil and natural gas prices are currently unregulated, Congress historically has been active in the area of oil and natural gas regulation. We cannot predict whether new legislation to regulate oil and natural gas might be proposed, what proposals, if any, might actually be enacted by Congress or

100

the various state legislatures, and what effect, if any, the proposals might have on our operations. Sales of condensate, oil and NGLs are not currently regulated and are made at market prices.

        Drilling and Production.    Our operations are subject to various types of regulation at the federal, state and local level. These types of regulation include requiring permits for the drilling of wells, drilling bonds and reports concerning operations. The state, and some counties and municipalities, in which we operate also regulate one or more of the following:

•

the location of wells;

•

the method of drilling and casing wells;

•

the timing of construction or drilling activities, including seasonal wildlife closures;

•

the rates of production or "allowables";

•

the surface use and restoration of properties upon which wells are drilled;

•

the plugging and abandonment of wells; and

•

notice to, and consultation with, surface owners and other third parties.

        State laws regulate the size and shape of drilling and spacing units or proration units governing the pooling of oil and natural gas properties. Some states allow forced pooling or integration of tracts to facilitate exploration while other states rely on voluntary pooling of lands and leases. In some instances, forced pooling or unitization may be implemented by third parties and may reduce our interest in the unitized properties. In addition, state conservation laws establish maximum rates of production from oil and natural gas wells, generally prohibit the venting or flaring of natural gas and impose requirements regarding the ratability of production. These laws and regulations may limit the amount of oil and natural gas we can produce from our wells or limit the number of wells or the locations at which we can drill. Moreover, each state generally imposes a production or severance tax with respect to the production and sale of oil, natural gas and NGLs within its jurisdiction. States do not regulate wellhead prices or engage in other similar direct regulation, but we cannot assure you that they will not do so in the future. The effect of such future regulations may be to limit the amounts of oil and natural gas that may be produced from our wells, negatively affect the economics of production from these wells or to limit the number of locations we can drill.

        Federal, state and local regulations provide detailed requirements for the abandonment of wells, closure or decommissioning of production facilities and pipelines and for site restoration in areas where we operate. The U.S. Army Corps of Engineers and many other state and local authorities also have regulations for plugging and abandonment, decommissioning and site restoration. Although the U.S. Army Corps of Engineers does not require bonds or other financial assurances, some state agencies and municipalities do have such requirements.

        Natural Gas Sales and Transportation.    Historically, federal legislation and regulatory controls have affected the price of the natural gas we produce and the manner in which we market our production. FERC has jurisdiction over the transportation and sale for resale of natural gas in interstate commerce by natural gas companies under the Natural Gas Act of 1938 and the Natural Gas Policy Act of 1978. Since 1978, various federal laws have been enacted which have resulted in the complete removal of all price and non-price controls for sales of domestic natural gas sold in "first sales," which include all of our sales of our own production. Under the Energy Policy Act of 2005, FERC has substantial enforcement authority to prohibit the manipulation of natural gas markets and enforce its rules and orders, including the ability to assess substantial civil penalties.

        FERC also regulates interstate natural gas transportation rates and service conditions and establishes the terms under which we may use interstate natural gas pipeline capacity, which affects the marketing of natural gas that we produce, as well as the revenues we receive for sales of our natural

101

gas and release of our natural gas pipeline capacity. Commencing in 1985, FERC promulgated a series of orders, regulations and rule makings that significantly fostered competition in the business of transporting and marketing gas. Today, interstate pipeline companies are required to provide nondiscriminatory transportation services to producers, marketers and other shippers, regardless of whether such shippers are affiliated with an interstate pipeline company. FERC's initiatives have led to the development of a competitive, open access market for natural gas purchases and sales that permits all purchasers of natural gas to buy gas directly from third-party sellers other than pipelines. However, the natural gas industry historically has been very heavily regulated; therefore, we cannot guarantee that the less stringent regulatory approach currently pursued by FERC and Congress will continue indefinitely into the future nor can we determine what effect, if any, future regulatory changes might have on our natural gas related activities.

        Under FERC's current regulatory regime, transmission services must be provided on an open-access, non-discriminatory basis at cost-based rates or at market-based rates if the transportation market at issue is sufficiently competitive. Gathering service, which occurs upstream of jurisdictional transmission services, is regulated by the states onshore and in state waters. Although its policy is still in flux, FERC has in the past reclassified certain jurisdictional transmission facilities as non-jurisdictional gathering facilities, which has the tendency to increase our costs of transporting gas to point-of-sale locations.

        Oil Sales and Transportation.    Sales of crude oil, condensate and NGLs are not currently regulated and are made at negotiated prices. Nevertheless, Congress could reenact price controls in the future.

        Our crude oil sales are affected by the availability, terms and cost of transportation. The transportation of oil in common carrier pipelines is also subject to rate regulation. FERC regulates interstate oil pipeline transportation rates under the Interstate Commerce Act and intrastate oil pipeline transportation rates are subject to regulation by state regulatory commissions. The basis for intrastate oil pipeline regulation, and the degree of regulatory oversight and scrutiny given to intrastate oil pipeline rates, varies from state to state. Insofar as effective interstate and intrastate rates are equally applicable to all comparable shippers, we believe that the regulation of oil transportation rates will not affect our operations in any materially different way than such regulation will affect the operations of our competitors.

        Further, interstate and intrastate common carrier oil pipelines must provide service on a non-discriminatory basis. Under this open access standard, common carriers must offer service to all shippers requesting service on the same terms and under the same rates. When oil pipelines operate at full capacity, access is governed by prorationing provisions set forth in the pipelines' published tariffs. Accordingly, we believe that access to oil pipeline transportation services generally will be available to us to the same extent as to our competitors.

        State Regulation.    Texas regulates the drilling for, and the production, gathering and sale of, oil and natural gas, including imposing severance taxes and requirements for obtaining drilling permits. Texas imposes a 4.6% severance tax on oil production and a 7.5% severance tax on natural gas production. States also regulate the method of developing new fields, the spacing and operation of wells and the prevention of waste of natural gas resources. States may regulate rates of production and may establish maximum daily production allowables from natural gas wells based on market demand or resource conservation, or both. States do not regulate wellhead prices or engage in other similar direct economic regulation, but we cannot assure you that they will not do so in the future. The effect of these regulations may be to limit the amount of natural gas that may be produced from our wells and to limit the number of wells or locations we can drill.

        The petroleum industry is also subject to compliance with various other federal, state and local regulations and laws. Some of those laws relate to resource conservation and equal employment

102

opportunity. We do not believe that compliance with these laws will have a material adverse effect on us.

Operational Hazards and Insurance

        The oil and natural gas industry involves a variety of operating risks, including the risk of fire, explosions, blow outs, pipe failures and, in some cases, abnormally high pressure formations which could lead to environmental hazards such as oil spills, natural gas leaks and the discharge of toxic gases. If any of these should occur, we could incur legal defense costs and could be required to pay amounts due to injury, loss of life, damage or destruction to property, natural resources and equipment, pollution or environmental damage, regulatory investigation and penalties and suspension of operations.

        In accordance with what we believe to be industry practice, we maintain insurance against some, but not all, of the operating risks to which our business is exposed. We have insurance policies for property (including leased oil and natural gas properties), general liability, operational control of certain wells, pollution, commercial auto, umbrella liability, inland marine, workers' compensation and other coverage. The limits for certain of our policies are as follows:

•

oil and natural gas lease property/inland marine: $790,370 on owned equipment, $100,000 per item/occurrence on rented or leased equipment, with a deductible of $2,500;

•

general liability: $1,000,000 per occurrence and $2,000,000 in the aggregate with no deductible (this coverage includes sudden and accidental pollution);

•

umbrella liability: $25,000,000 per occurrence with $25,000,000 aggregate coverage; and

•

control of well: $10,000,000 with a deductible per accident ranging from $75,000 to $150,000 based on feet in depth.

        As noted above, most of our insurance coverage includes deductibles that must be met prior to recovery. Additionally, our insurance is subject to exclusion and limitations, and there is no assurance that such coverage will fully or adequately protect us against liability from all potential consequences, damages and losses. Any of these operational hazards could cause a significant disruption to our business. A loss not fully covered by insurance could have a material adverse effect on our financial condition, results of operations and cash flows.

        We reevaluate the purchase of insurance, policy terms and limits annually. Future insurance coverage for our industry could increase in cost and may include higher deductibles or retentions. In addition, some forms of insurance may become unavailable in the future or unavailable on terms that we believe are economically acceptable. No assurance can be given that we will be able to maintain insurance in the future at rates that we consider reasonable and we may elect to maintain minimal or no insurance coverage. We may not be able to secure additional insurance or bonding that might be required by new governmental regulations. This may cause us to restrict our operations, which might severely impact our financial condition. The occurrence of a significant event, not fully insured against, could have a material adverse effect on our financial condition and results of operations.

        Generally, we also require our third party vendors to sign master service agreements in which they agree to indemnify us for injuries and deaths of the service provider's employees as well as contractors and subcontractors hired by the service provider.

Employees

        As of May 31, 2013, we had 57 full time employees, including four geologists, 11 engineers and eight land professionals, 43 of whom are salaried administrative or supervisory employees. Of these 57 full time employees, 31 work in our corporate headquarters. None of our employees are represented by labor unions or covered by any collective bargaining agreements. We also hire independent contractors

103

and consultants involved in land, technical, regulatory and other disciplines to assist our full time employees. We consider our relations with our employees to be satisfactory.

Facilities

        Our corporate headquarters is located in Fort Worth, Texas. We also lease additional office space in Midland, Texas. We believe that our facilities are adequate for our current operations.

Legal Proceedings

        From time to time, we are a party to ongoing legal proceedings in the ordinary course of business, including workers' compensation claims and employment related disputes. We do not believe the results of these proceedings, individually or in the aggregate, will have a material adverse effect on our business, financial condition, results of operations or liquidity.

104

MANAGEMENT

Directors and Executive Officers

        The following sets forth information regarding our directors and officers:

Name	Age		Position with Athlon
Robert C. Reeves		43	President, Chief Executive Officer and Director
Nelson K. Treadway		47	Senior Vice President—Business Development and Land
William B. D. Butler		36	Vice President and Chief Financial Officer
Melvyn E. Foster		44	Vice President—Reservoir Engineering
Bud W. Holmes		46	Vice President—Engineering and Operations
David B. McClelland		42	Vice President—Drilling and Geosciences
Jennifer L. Palko		39	Vice President—Business Development and Engineering
James R. Plemons		45	Vice President—Business Development and Land
John C. Souders		42	Vice President—Controller
Gregory A. Beard		41	Director
Sam Oh		42	Director
Rakesh Wilson		38	Director
Ted A. Gardner		55	Director Nominee

        Robert C. Reeves—President, Chief Executive Officer and Director.    Mr. Reeves has been Athlon's President and Chief Executive Officer since its formation in August 2010. Prior to Athlon's formation, Mr. Reeves was Senior Vice President, Chief Financial Officer and Treasurer of Encore Energy Partners GP LLC, the general partner of Encore Energy Partners LP, from February 2007 until March 2010, and Corporate Secretary from May 2008 to August 2010. Mr. Reeves was also the Senior Vice President, Chief Financial Officer and Treasurer of Encore Acquisition Company ("EAC") from November 2006 until March 2010, and Corporate Secretary from May 2008 to August 2010. Mr. Reeves served as Senior Vice President, Chief Accounting Officer, Controller and Assistant Corporate Secretary of EAC from November 2005 until November 2006. He served as EAC's Vice President, Controller and Assistant Corporate Secretary from August 2000 until October 2005. He served as Assistant Controller of EAC from April 1999 until August 2000. Prior to joining EAC, Mr. Reeves served as Assistant Controller for Hugoton Energy Corporation. Mr. Reeves received his Bachelor of Science degree in Accounting from the University of Kansas. He is a Certified Public Accountant. Based upon Mr. Reeves' extensive background in operations and management, having served in various high-level executive roles, as well as his strong financial background and his experience with Athlon, which provide him with a unique understanding of our business and the operational, financial and strategic issues that energy companies face, we believe that Mr. Reeves possesses the requisite set of skills to serve as a member of our Board of Directors.

        Nelson K. Treadway—Senior Vice President—Business Development and Land.    Mr. Treadway has been Athlon's Senior Vice President—Business Development and Land since its formation in August 2010. Prior to Athlon's formation, Mr. Treadway served as Senior Vice President—Land of Encore Energy Partners GP LLC and EAC from February 2008 to March 2010. Mr. Treadway served as Vice President—Land of EAC from April 2003 to February 2008. He served as a Vice President—Land at Encore Energy Partners GP LLC from February 2007 to February 2008. From May 2000 to April 2003, Mr. Treadway held various positions of increasing responsibility in EAC's land department. Prior to EAC, he served as a landman at Coho Resources. Mr. Treadway received a Bachelor of Science degree in Petroleum Land Management from the University of Southwestern Louisiana.

        William B. D. Butler—Vice President and Chief Financial Officer.    Mr. Butler has been Athlon's Vice President and Chief Financial Officer since March 2013. Prior to joining Athlon, Mr. Butler served as Managing Director for Stephens Inc. from August 2010 to March 2013, where he developed and led its Exploration & Production research practice. Previously, he was Vice President and Assistant Treasurer

105

of XTO Energy Inc. from June 2003 until June 2010. During his seven-year tenure, XTO completed 21 capital raises, including public equity, senior notes and bank debt, for more than $15 billion in aggregate proceeds to fund XTO's growth strategy. From June 2000 to June 2003, Mr. Butler served at Stephens Inc. as an investment banker. Mr. Butler received a Bachelor of Science degree in Commerce from Washington & Lee University with special attainments in Business Administration and History.

        Melvyn E. Foster—Vice President—Reservoir Engineering.    Mr. Foster has been Athlon's Vice President—Reservoir Engineering since its formation in August 2010. Prior to Athlon's formation, Mr. Foster was Reservoir Engineering Manager—North Region of Denbury Resources, Inc. from April 2010 to August 2010. Mr. Foster was Northern Region Reservoir Engineering Manager of EAC from December 2007 to April 2010. From April 2002 to December 2007, Mr. Foster held various positions of increasing responsibility in EAC's engineering department. Prior to EAC, he served in various engineering positions at Phillips Petroleum Company. Mr. Foster received his Bachelor of Science degree in Petroleum Engineering from the University of Texas at Austin and his Master of Science degree in Petroleum Engineering from the University of Houston.

        Bud W. Holmes—Vice President—Engineering and Operations.    Mr. Holmes has been Athlon's Vice President—Engineering and Operations since its formation in August 2010. Prior to Athlon's formation, Mr. Holmes served as Northern Region Production Manager and member of the Strategic Management Team of EAC from October 2003 until March 2010. Mr. Holmes served as Northern Region Senior Operations Engineer from April 2001 until October 2003. Prior to joining EAC, Mr. Holmes served in various reservoir, production and drilling engineering positions for Louis Dreyfus Natural Gas, Union Pacific Resources and Shell Western E&P. Mr. Holmes received his Bachelor of Science degree in Petroleum Engineering from the University of Oklahoma, graduating with top honors.

        David B. McClelland—Vice President—Drilling and Geosciences.    Mr. McClelland has been Athlon's Vice President—Drilling and Geosciences since its formation in August 2010. Prior to Athlon's formation, Mr. McClelland was the Geoscience Manager—Southern Region for EAC, from February 2007 to June 2010, and he was a Senior Geologist from March 2004 to January 2007 at EAC. Prior to EAC, he was a Geologist at Anadarko Petroleum Company and held various geosciences positions at Union Pacific Resources and Cross Timbers Oil Company. Mr. McClelland received his Bachelor of Science degree in Geology from the University of Texas at Arlington. He also received his Master of Science degree in Geology from the University of Texas at Arlington. Mr. McClelland is a licensed professional geoscientist in the State of Texas, and is a 16 year member of the American Association of Petroleum Geologists.

        Jennifer L. Palko—Vice President—Business Development and Engineering.    Ms. Palko has been Athlon's Vice President—Business Development and Engineering since its formation in August 2010. Prior to Athlon's formation, Ms. Palko served as the Reserves & Planning Engineering Manager and a member of the Strategic Management Team of EAC from October 2003 until March 2010. Prior to serving as the Reserves & Planning Engineering Manager, Ms. Palko held various positions of increasing responsibility in EAC's engineering department from May 2001 until October 2003. Prior to joining EAC, Ms. Palko served as an Independent Petroleum Consultant at Cawley, Gillespie & Associates, Inc. from September 2000 until May 2001. Prior to joining Cawley, Gillespie & Associates, Inc., Ms. Palko served in various reservoir and operations engineering positions at Union Pacific Resources from May 1995 until September 2000. Ms. Palko received her Bachelor of Science degree in Petroleum Engineering from Texas A&M University, graduating first in her class with top honors.

        James R. Plemons—Vice President—Business Development and Land.    Mr. Plemons has been Athlon's Vice President—Business Development and Land since its formation in August 2010. Prior to the Partnership's formation, Mr. Plemons served as the Southern Region Land Manager of Encore Energy Partners GP LLC and EAC from January 2007 to June 2010. Prior to serving as Southern Region Land Manager, Mr. Plemons served in several roles with increasing responsibility in EAC's land department from June 2004 to December 2006. Prior to EAC, he served as a landman at Wagner Oil

106

Company. Mr. Plemons received a Bachelor of Science degree in Marketing from Sam Houston State University.

        John C. Souders—Vice President—Controller.    Mr. Souders has been Athlon's Vice President—Controller since July 2011 and was Director of Accounting from March 2011 until his promotion in July 2011. Prior to Athlon's formation, Mr. Souders served as a Senior Accounting Manager at EAC from May 2007 until February 2011. Prior to EAC, Mr. Souders served as an Accounting Manager at Sabre Holdings and as an auditor at Ernst & Young. Mr. Souders has a Bachelor of Science degree in Economics from Texas A&M University and a Masters in Accounting from North Texas University. He is a Certified Public Accountant.

        Gregory A. Beard—Director.    Mr. Beard is currently a Senior Partner at Apollo. Mr. Beard joined the firm in June 2010 as the Global Head of Natural Resources, based in the New York office. Mr. Beard joined Apollo with 19 years of investment experience, the last ten of which were with Riverstone Holdings where he was a founding member, Managing Director and lead deal partner in many of the firm's top oil and natural gas and energy service investments. While at Riverstone, Mr. Beard was involved in all aspects of the investment process including sourcing, structuring, monitoring and exiting transactions. Mr. Beard began his career as a Financial Analyst at Goldman Sachs, where he played an active role in that firm's energy-sector principal investment activities. Mr. Beard has served on the board of directors of many oil and natural gas companies including Apex Energy, EP Energy, Belden & Blake Corporation, Canera Resources, Cobalt International Energy, Eagle Energy, Legend Natural Gas I—IV, Mariner Energy, Phoenix Exploration, Titan Operating, Talos Energy, Pinnacle Agriculture Holdings, LLC, NRI Management Group, LLC and Vantage Energy. Mr. Beard has also served on the board of directors of various oilfield services companies, including CDM Max, CDM Resource Management and International Logging. Mr. Beard received his Bachelor of Arts degree from the University of Illinois at Urbana. Based upon Mr. Beard's extensive investment and management experience, particularly in the energy sector, his strong financial background and his service on the boards of multiple oil and natural gas exploration and production companies and oilfield services companies, which have provided him with a deep working knowledge of our operating environment, we believe that he possesses the requisite skills to serve as a member of our Board of Directors.

        Sam Oh—Director.    Mr. Oh is currently a Senior Partner at Apollo. Mr. Oh joined the firm in April 2008 and is one of the original founding members of Apollo's Natural Resources group. Prior to joining Apollo, Mr. Oh was with Morgan Stanley's Commodities Department where he led principal investments for the group. While at Morgan Stanley, Mr. Oh launched a successful oil and natural gas fund, Helios Energy/Royalty Partners, and sat on the board of several portfolio companies. Mr. Oh has 18 years of experience, including 13 years of principal investing. He also has a broad range of experience in the commodities markets including risk management and structured products. Since joining Apollo, Mr. Oh has been actively involved in Apollo's E&P investments, including leading the Parallel Petroleum acquisition in 2009. Mr. Oh was formerly Chairman of the Board of Parallel Petroleum and is a director of EP Energy. Mr. Oh received a Bachelor of Science degree from the University of Pennsylvania's Wharton School of Business and an MBA from the Yale School of Management. He is also a Certified Public Accountant and a Chartered Financial Analyst. Based upon Mr. Oh's strong management experience and extensive background in commodities markets having overseen various complex commodities investments, as well as his experience with Athlon and his service on multiple boards of directors, we believe that Mr. Oh possesses the requisite set of skills to serve as a member of our Board of Directors.

        Rakesh Wilson—Director.    Mr. Wilson is currently a Principal at Apollo. Mr. Wilson joined the firm in March 2009, where he is currently a senior member of Apollo's Natural Resources group. Prior to joining Apollo, Mr. Wilson was at Morgan Stanley's Commodities Department in the principal investing group responsible for generating, evaluating and executing investment ideas across the energy sector

107

with deals including Wellbore Capital and Helios Energy/Royalty Partners. Mr. Wilson began his career at Goldman Sachs in equity research and then moved to its investment banking division in New York and Asia. Mr. Wilson currently serves on the boards of directors of EP Energy and Talos Energy and previously served as a director of Parallel Petroleum. Mr. Wilson graduated from the University of Texas at Austin and received his MBA from INSEAD, Fontainebleau, France. He has also taught business courses at universities in China. We believe that Mr. Wilson's extensive international investment and risk management experience, his knowledge of Athlon and his service on multiple boards have provided him with a strong understanding of the financial, operational and strategic issues facing public companies in our industry, and that he possesses the requisite set of skills to serve as a member of our Board of Directors.

        Ted A. Gardner—Director Nominee.    Mr. Gardner has agreed to serve as a director of Athlon and will become a member of the board of directors prior to the listing of our common stock on the NYSE. Mr. Gardner has been a Managing Partner of Silverhawk Capital Partners in Charlotte, North Carolina since 2005. Mr. Gardner is also currently a director of Summit Materials Holdings, Spartan Energy Partners, Kinder Morgan Management, LLC and Kinder Morgan G.P., Inc. Formerly, he was a director and Chairman of the Compensation Committee of Kinder Morgan, Inc. from 1999 to 2007 and was a director and Chairman of the Audit Committee of Encore Acquisition Company from 2001 to 2010. Mr. Gardner also served as Managing Partner of Wachovia Capital Partners and was a Senior Vice President of Wachovia Corporation from 1990 to June 2003. Based upon his prior management, business and leadership experience, as well as his previous board experience with other publicly-held companies in the energy sector, we believe that Mr. Gardner possesses the requisite set of skills to serve as a member of our Board of Directors.

Composition of Our Board of Directors

        Upon the closing of this offering, it is anticipated that we will have five directors. Assuming the Apollo Funds continue to control more than 50% of our common stock, we intend to avail ourselves of the "controlled company" exception under NYSE rules, which eliminates the requirements that we have a majority of independent directors on our Board of Directors and that we have a compensation committee and a nominating and corporate governance committee, each composed entirely of independent directors. We will be required, however, to have an audit committee comprised entirely of independent directors within the permitted "phase-in" period under NYSE rules.

        The stockholders agreement that we will enter into in connection with this offering will provide that, except as otherwise required by applicable law, if the Apollo Funds hold: (a) at least 50% of our outstanding common stock, they will have the right to designate no fewer than that number of directors that would constitute a majority of our Board of Directors; (b) at least 30% but less than 50% of our outstanding common stock, they will have the right to designate up to three director nominees; (c) at least 20% but less than 30% of our outstanding common stock, they will have the right to designate up to two director nominees; and (d) at least 10% but less than 20% of our outstanding common stock, they will have the right to designate up to one director nominee. The agreement also provides that if the size of our Board of Directors is increased or decreased at any time to other than seven directors, the Apollo Funds' nomination rights will be proportionately increased or decreased, respectively, rounded up to the nearest whole number. In addition, the agreement provides that if the Apollo Funds hold at least 30% of our outstanding common stock, we will cause any committee of our Board of Directors to include in its membership at least one of the Apollo Funds nominees, except to the extent that such membership would violate applicable securities laws or stock exchange or stock market rules. As a result of the size of their ownership of our common stock, the Apollo Funds will be able to control matters requiring stockholder approval, including the election of directors, changes to our organizational documents and significant corporate transactions.

        If at any time we cease to be a "controlled company" under NYSE rules (including upon completion of this offering and the related transactions), the Board of Directors will take all action

108

necessary to comply with the NYSE rules, including appointing a majority of independent directors to the Board of Directors and ensuring we have a compensation committee and a nominating and corporate governance committee, each composed entirely of independent directors, subject to a permitted "phase-in" period. We will cease to qualify as a "controlled company" once the Apollo Funds cease to control a majority of our voting stock.

        Following the closing of this offering, our Board of Directors will be divided into three classes. The members of each class will serve staggered, three-year terms (other than with respect to the initial terms of the Class I and Class II directors, which will be one and two years, respectively). Upon the expiration of the term of a class of directors, directors in that class will be elected for three-year terms at the annual meeting of stockholders in the year in which their term expires. Following the completion of this offering:

•

Sam Oh and Rakesh Wilson will be Class I directors, whose initial terms will expire at the 2014 annual meeting of stockholders;

•

Ted A. Gardner and Robert C. Reeves will be Class II directors, whose initial terms will expire at the 2015 annual meeting of stockholders; and

•

Gregory A. Beard will be a Class III director, whose initial term will expire at the 2016 annual meeting of stockholders.

        Any additional directorships resulting from an increase in the number of directors will be distributed among the three classes so that, as nearly as possible, each class will consist of one-third of our directors. This classification of our Board of Directors may have the effect of delaying or preventing changes in control.

        At each annual meeting following completion of this offering, our stockholders will elect certain of our directors. Our executive officers and key employees serve at the discretion of our Board of Directors. Directors may be removed for cause by the affirmative vote of the holders of a majority of our common stock so long as at least 33¹/3% of the voting power of all our shares is owned by the Apollo Funds and the Apollo Funds cast their votes in favor of the proposed action. At any other time, directors may be removed for cause only by the affirmative vote of at least 66²/3% of the voting power of our common stock.

Apollo Approval of Certain Matters

        Under the stockholders agreement that we have agreed to enter into with the Apollo Funds and certain stockholders upon consummation of this offering, until such time as the Apollo Funds no longer beneficially own at least 33¹/3% of our outstanding common stock, a majority of the Board of Directors, including a majority of the directors designated to our Board of Directors by the Apollo Funds, must approve certain of our significant business decisions before we are permitted to take action, including each of the following:

•

amending, modifying or repealing any provision of our certificate of incorporation and bylaws or similar organization documents in a manner that adversely affects the Apollo Funds or their affiliates;

•

issuing additional equity interests other than any (i) award under any stockholder-approved equity compensation plan, (ii) intra-company issuance among our subsidiaries and us or (iii) issuance of equity interests pursuant to the exchange agreement;

•

consolidating or merging with or into any other entity, transferring all or substantially all of our and our subsidiaries' assets, taken as a whole, to another entity or entering into or agreeing to undertake any transaction that would constitute a "Change of Control" as defined in our credit agreement or the indenture governing our senior notes;

109

•

disposing of any of our or any of our subsidiaries' assets with a value in excess of $100 million in any single transaction or $200 million in the aggregate in any series of transactions during a calendar year;

•

consummating any acquisition by us or any of our subsidiaries of the equity interests or assets of any other entity involving consideration in excess of $100 million in any single transaction or $200 million in the aggregate in any series of transactions during a calendar year;

•

incurring any indebtedness by us or any of our subsidiaries (including through capital leases, the issuance of debt securities or the guarantee of indebtedness of another entity) that would result in our total net indebtedness to adjusted EBITDA for the trailing twelve-month period exceeding 2.50 to 1.0;

•

terminating our Chief Executive Officer or designating a new Chief Executive Officer; and

•

changing the size of our Board of Directors.

        Please read "—Composition of Our Board of Directors" for a description of the Apollo Funds' rights to nominate a certain number of directors.

Director Independence

        Our Board of Directors has determined that, under NYSE listing standards and taking into account any applicable committee standards and rules under the Exchange Act, Mr. Gardner is an independent director. Within 90 days of our listing on the NYSE, we will appoint at least one additional independent director. Within one year of the date of effectiveness of the registration statement, we will appoint a third independent director. Mr. Reeves is not considered independent under any general listing standards due to his current employment relationship with us, and Messrs. Beard, Oh and Wilson, are not considered independent under any general listing standards due to their relationship with the Apollo Funds, our largest stockholder.

Committees of the Board of Directors

        Prior to the listing of our common stock on the NYSE, we intend to have an Audit Committee, a Compensation Committee and a Nominating and Corporate Governance Committee, and may have such other committees as the Board of Directors shall determine from time to time. Each of the standing committees of the Board of Directors will have the composition and responsibilities described below.

Audit Committee

        Mr. Gardner will serve as the initial member of our Audit Committee. Within 90 days of our listing on the NYSE we will appoint another independent director to our Audit Committee. Our Board of Directors has determined that Mr. Gardner is an Audit Committee financial expert as defined by the SEC. Each member of the Audit Committee meets or will meet criteria for independence of Audit Committee members set forth in Rule 10A-3(b)(1) under the Exchange Act.

        The principal duties of the Audit Committee are to assist the Board of Directors in fulfilling its responsibility to oversee management regarding:

•

systems of internal control over financial reporting and disclosure controls and procedures;

•

the integrity of the financial statements;

•

the qualifications, engagement, compensation, independence and performance of the independent auditors and our internal audit function;

•

compliance with legal and regulatory requirements;

110

•

review of material related party transactions; and

•

compliance with and adequacy of the code of business and ethics, review and, if appropriate, approve any requests for written waivers sought with respect to any executive officer or director under, the code of business and ethics.

Compensation Committee

        Robert C. Reeves, Gregory A. Beard, Sam Oh, Rakesh Wilson and Ted A. Gardner will serve as the initial members of our Compensation Committee. The principal duties of the Compensation Committee are to:

•

oversee our management compensation policies and practices, including, without limitation, (i) determining and approving the compensation of the Chief Executive Officer and our other executive officers, (ii) reviewing and approving management incentive policies and programs and exercising any applicable rule making or discretion in the administration of such programs, (iii) reviewing and approving equity compensation programs for employees, and exercising any applicable rule making or discretion in the administration of such programs and (iv) reviewing and approving any share ownership and clawback policies applicable to the senior management group or other employees;

•

set and review the compensation of and reimbursement and share ownership policies for members of our Board of Directors;

•

provide oversight concerning the selection of officers, expense accounts and severance plans and policies and compliance with all compensation and benefits-related legal and regulatory matters;

•

review and discuss with management our compensation discussion and analysis to be included in our annual proxy statement or annual report on Form 10-K filed with the SEC; and

•

prepare an annual Compensation Committee report, provide regular reports to our Board of Directors, and take such other actions as are necessary and consistent with the governing law and our organizational documents.

Nominating and Corporate Governance Committee

        Gregory A. Beard, Sam Oh and Rakesh Wilson will serve as the initial members of our Nominating and Corporate Governance Committee. The principal duties and responsibilities of our Nominating and Corporate Governance Committee will be the following:

•

implementation and review of criteria for membership on our Board of Directors and its committees;

•

identification and recommendation of proposed nominees for election to our Board of Directors and membership on its committees;

•

development of and recommendation to our Board of Directors regarding governance and related matters; and

•

overseeing the evaluation of our Board of Directors.

Code of Ethics

        Our Board of Directors has adopted a code of business conduct and ethics (the "Code of Conduct") that applies to all directors, officers and employees, including our principal executive officer, principal financial officer and principal accounting officer. Upon the closing of this offering, the Code of Conduct will be available in the Corporate Governance section of our website at www.athlonenergy.com. The contents of our website are not incorporated by reference herein or

111

otherwise a part of this prospectus. The purpose of the Code of Conduct is to promote honest and ethical conduct, including the ethical handling of actual or apparent conflicts of interest between personal and professional relationships; to promote full, fair, accurate, timely and understandable disclosure in periodic reports required to be filed by us; and to promote compliance with all applicable rules and regulations that apply to us and our officers.

Corporate Governance Guidelines

        Our Board of Directors will adopt corporate governance guidelines in accordance with the corporate governance rules of the NYSE.

Executive Compensation

        This executive compensation disclosure provides an overview of the 2012 executive compensation program for our named executive officers ("NEOs") identified below. For 2012, our NEOs were:

•

Robert C. Reeves, President, Chief Executive Officer and Director;

•

Nelson K. Treadway, Senior Vice President—Business Development and Land; and

•

David B. McClelland, Vice President—Drilling and Geosciences.

Summary Compensation Table

        The following summarizes the total compensation awarded to, earned by or paid to our NEOs for 2012:

Name and Principal Position	Year		Salary ($)		Non-Equity Incentive Plan Compensation ($)1		All Other Compensation ($)2		Total ($)
Robert C. Reeves, President, Chief Executive Officer and Director		2012	$	374,583	$	385,000	$	26,539	$	786,122
Nelson K. Treadway, Senior Vice President—Business Development and Land		2012		279,375		206,225		22,401		508,001
David B. McClelland, Vice President—Drilling and Geosciences		2012		219,792		117,150		20,865		357,807

¹

Represents cash bonuses paid to our NEOs under our incentive program with respect to 2012 company and individual performance. For additional information, please read "—Narrative Disclosure to Summary Compensation Table—Cash Bonuses" below.

²

Represents employer contributions under our 401(k) plan.

112

Narrative Disclosure to Summary Compensation Table

        The primary elements of compensation for the NEOs are base salary, cash bonuses and long-term equity-based compensation awards. The NEOs also receive certain retirement, health, welfare and additional benefits as described below.

Compensation Element	Characteristics	Primary Objective
Base salary	Fixed annual cash compensation. Salaries may be increased from time to time based on the NEOs' responsibilities and performance.	Recognize performance of job responsibilities and attract and retain talented employees.
Cash bonuses	Performance-based semi-annual cash incentive.	Encourage focus on near-term performance goals and reward achievement of those goals.
Long-term equity incentives	Equity-based compensation awards subject to time-vesting provisions.	Emphasize our long-term growth, encourage maximizing equity value and retain talented employees.
Severance provisions	Salary continuation and COBRA reimbursement upon certain qualifying terminations.	Encourage continued attention and dedication of key individuals and focus their attention when considering strategic alternatives.
Retirement savings 401(k) plan	Qualified 401(k) retirement plan benefits are available for our NEOs and all other full-time employees.	Provide an opportunity for tax-efficient savings.
Health and welfare benefits	Health and welfare benefits are available to our NEOs and other full-time employees.	Provide benefits to meet the health and welfare needs of our employees and their families.

        Base Salary.    Base salaries for our NEOs have generally been set at levels deemed necessary to attract and retain individuals with superior talent. While the Board will review and may adjust each NEO's salary from time to time, Messrs. Treadway's and McClelland's employment agreements provide that their respective salary will not be reduced for two years after the effective date of his agreement and Mr. Reeves' employment agreement provides that his base salary will never be reduced.

        In September 2012, the Board approved salary increases for our NEOs based upon the responsibilities and performance of each NEO as well as market conditions. Our NEOs' base salaries will also be increased upon the closing of this offering to better align total compensation with

113

competitive pay levels for similarly situated public companies. The base salaries of our NEOs before and after the 2012 increase and after the offering are set forth in the following table:

Name and Principal Position	Base Salary Before 2012 Increase		Base Salary After 2012 Increase		Base Salary After the Offering
Robert C. Reeves	$	360,000	$	410,000	$	570,000
Nelson K. Treadway		275,000		290,000		300,000
David B. McClelland1		215,000		240,000		275,000

¹

Mr. McClelland received an additional salary adjustment in April 2012 that increased his base salary from $205,000 to $215,000.

        Cash Bonuses.    Each of our NEOs is eligible to participate in a semi-annual cash incentive program which provides participants with an opportunity to earn cash bonus awards generally based on individual and company performance. Target bonus levels for each of our NEOs other than Mr. Reeves are established by the Board of Directors at the beginning of each year, subject to mid-year adjustment, and are based on a percentage of their respective base salary. Mr. Reeves' target bonus level of 100% is set forth in his employment agreement and was established based upon individual negotiations at the time of his commencement of employment. For 2012, Mr. Treadway had a target bonus level of 73%. Mr. McClelland had a target bonus level of 43% for the first half of 2012 and 60% for the second half of 2012. Upon the closing of this offering, Mr. Treadway's and Mr. McClelland's target bonus levels will be adjusted to 80% and 70% of their annual base salaries, respectively.

        Historically, including for 2012, with respect to assessment of company performance, the bonus awards for our NEOs have not been based on specific pre-determined performance targets or goals. Rather, we have generally considered our overall operational performance for the applicable year as a guide in determining award payout levels and have maintained discretion to adjust awards in circumstances where individual performance may warrant such an adjustment. For 2012, we determined to pay bonuses to each of our NEOs 100% of their respective target bonus levels and did not make any individual performance adjustments to these awards. Our decision in this regard was based primarily on generally attaining budgeted levels for the year with respect to certain operational performance metrics, which included rate of return on drilling capital, our net asset value, drilling costs per well, production volumes and LOE per BOE. We focused on operating metrics of this type in determining cash bonus awards for our NEOs, rather than on financial metrics such as revenue or net income because such financial metrics are influenced by commodity prices, which can fluctuate based on macro-economic factors that are beyond the control of our NEOs.

        Long-Term Equity-Based Compensation Awards.    None of our NEOs received awards or grants of equity or equity-based compensation during 2012. However, in August 2010, each of our NEOs was granted Class B limited partner interests of Athlon Holdings LP pursuant to the Athlon Holdings LP Limited Partnership Agreement. The Class B limited partner interests were intended to align the interests of our NEOs with those of our equity sponsor and provide a retention incentive for our NEOs.

        The Class B limited partner interests are profits interests that were intended to allow our NEOs to participate in the increase in value of Athlon Holdings LP from and after the date of grant of such interests. Class B limited partner interests are subject to time-vesting provisions. Mr. Reeves' Class B limited partner interests were scheduled to vest in equal monthly installments over a four-year period, beginning on the last date of the month of the grant date. Messrs. Treadway's and McClelland's Class B limited partner interests were scheduled to vest in equal semi-annual installments over a five-year period, beginning on the six-month anniversary of the grant date. Please read "—Severance and Change in Control Provisions" for a description of the other circumstances under which vesting of these awards may have accelerated. In connection with the reorganization as described under

114

"Corporate Reorganization," all of the Class B limited partner interests held by our NEOs and certain other employees were converted into shares of our common stock. For information regarding the number of our shares of common stock beneficially owned by each of our NEOs immediately following the consummation of this offering, please read "Principal and Selling Stockholders."

        In connection with this offering, we intend to adopt the Athlon Energy Inc. 2013 Incentive Award Plan, under which we expect to make periodic grants of equity and equity-based awards to our NEOs and other key employees, including awards expected to be granted shortly after the closing of this offering. For additional information, please read "—Executive Compensation Plans—2013 Incentive Award Plan."

        Retirement, Health, Welfare and Additional Benefits.    The NEOs are eligible to participate in such employee benefit plans and programs as we may from time to time offer to our other full-time employees, subject to the terms and eligibility requirements of those plans. The NEOs are also eligible to participate in a tax-qualified 401(k) defined contribution plan to the same extent as all of our other full-time employees. For 2012, we made a fully vested safe harbor non-elective contribution on behalf of each of the plan's participants equal to 3% of that participant's salary for the year.

Outstanding Equity Awards at December 31, 2012

        The outstanding Class B limited partner interests in Athlon Holdings LP held by our NEOs as of December 31, 2012 were as follows:

	Equity Awards
Name	Number of Class B Limited Partner Interests that Have not Vested (#)1			Market Value of Class B Limited Partner Interests That Have Not Vested ($)4
Robert C. Reeves		15,833	2	$	1,481,177
Nelson K. Treadway		7,200	3		673,560
David B. McClelland		3,150	3		294,683

¹

As discussed above under "—Summary Compensation Table—Narrative Disclosure to Summary Compensation Table—Long-Term Equity-Based Compensation Awards," the Class B limited partner interests were converted in anticipation of this offering into shares of our common stock.

²

Unvested Class B limited partner interests were scheduled to vest in equal monthly installments through the fourth anniversary of the date of grant in August 2010.

³

Unvested Class B limited partner interests were scheduled to vest in equal semi-annual installments through the fifth anniversary of the date of grant in August 2010.

⁴

Amount shown represents an estimate of fair market value of the unvested Class B limited partner interests as of December 31, 2012 of $93.55 per interest, as determined by an independent third-party valuation expert.

Employment Agreements

        We entered into an employment agreement with Mr. Reeves on August 23, 2010 for a term of three years, subject to automatic renewal for a one-year period, and with Messrs. Treadway and McClelland on August 23, 2010, each for a term of two years, subject to automatic renewal for a one-year period. In addition, in connection with the consummation of this offering, we are entering into new employment agreements with each of our NEOs. These agreements will provide for a similar initial term as the prior agreements and, as revised, contain (i) compensation provisions, including provisions regarding base salary, cash incentive bonuses and other benefits, (ii) termination and severance provisions (discussed more in detail below) and (iii) noncompete, nonsolicit and

115

nondisclosure provisions, with a restriction period of one year for the noncompete and nonsolicit provisions.

Severance and Change in Control Provisions

        Mr. Reeves' Severance and Change in Control Benefits.    Mr. Reeves' new employment agreement provides that if we terminate Mr. Reeves' employment for cause, he resigns without good reason or he does not extend his term of employment, then he is entitled to receive: (i) the portion of his base salary earned through the date of termination but not yet paid, plus any accrued vacation earned but not used through the date of termination; (ii) any cash incentive bonus earned but not yet paid; (iii) any expenses owed to him; and (iv) any amount accrued arising from his participation in, or benefits accrued under any employee benefits plans, programs or arrangements. Any rights to salary, cash bonus or other benefits will then cease.

        However, if Mr. Reeves is terminated without cause, resigns with good reason or we do not extend his term of employment and Mr. Reeves signs a release within 45 days, he is entitled, in addition to the items listed in the above paragraph, to (i) receive an amount of cash equal to four times the annual base salary in effect as of the date of termination payable 50% in a lump sum within 60 days following his separation from service and 50% over the subsequent twelve months, in accordance with regular payroll practices, and (ii) have us pay directly or reimburse him for COBRA premiums if he (or his dependents) elect to receive continued healthcare coverage pursuant to COBRA until the earlier of two years or the last day of the applicable COBRA period.

        In addition to the items listed in the paragraph above, if Mr. Reeves is terminated without cause, he resigns with good reason or we do not extend his term of employment, in any case within one year following the date of a change in control, then in lieu of the amount of cash listed above, he is entitled to receive an amount in cash equal to three times his annual base salary in effect as of the date of termination, plus three times the greater of the average of his previous two years' bonus payments or his target bonus.

        If Mr. Reeves is terminated due to death or disability and, in the case of disability, he signs a release within 45 days, he is additionally entitled to (i) receive an amount of cash equal to 25% of his base salary, payable in lump sum on the 60^th day following his separation from service and (ii) have us pay directly or reimburse him for COBRA premiums if he (or his dependents) elect to receive continued healthcare coverage pursuant to COBRA for three months.

        Good reason is defined in Mr. Reeves' employment agreement generally to mean the occurrence of any of the following events without his express written consent: (i) any reduction in his base salary; (ii) any material breach by us of the employment agreement; (iii) his duties or responsibilities for us or our successor are materially reduced or there is any material change in his title or any material change in the types of positions reporting to him or the type of position to whom he reports; or (iv) any transfer of his primary place of employment of more than 25 miles from 420 Throckmorton Street, Suite 1200, Fort Worth, Texas 76102, provided that such transfer increases his commute by more than 25 miles.

        In addition, Mr. Reeves' award agreement granting his Class B limited partner interests also contains certain termination and change in control provisions, under which all unvested Class B limited partner interests will fully vest upon (i) a change of control, winding up of Athlon Holdings LP's affairs, dissolution or liquidation of Athlon Holdings LP, (ii) a sale of all or substantially all of the assets of Athlon Holdings LP or (iii) the partners of Athlon Holdings LP receiving distributions from Athlon Holdings LP representing a return of their invested capital plus an 8% compounded annual return. If Mr. Reeves' employment is terminated for other than cause, due to death or disability or if he resigns for good reason, then half of his unvested Class B limited partner interests will vest upon his termination or resignation.

116

        Other NEOs' Severance and Change in Control Benefits.    Messrs. Treadway's and McClelland's new employment agreements provide that if either NEO's employment is terminated (i) for cause, due to death or disability, (ii) due to resignation without good reason or (iii) either party decides not to extend the term of employment, then each is entitled to (a) the portion of his base salary earned through the date of termination but not yet paid, plus any accrued vacation earned but not used through the date of termination, (b) any expenses owed to him and (c) any amount accrued arising from his participation in, or benefits accrued under any employee benefits plans, programs or arrangements. Any rights to salary, cash bonus or other benefits will then cease.

        However, if Messrs. Treadway or McClelland is terminated without cause or resigns for good reason and signs a release within 45 days, then each is entitled, in addition to the items listed in the above paragraph, to (i) receive an amount of cash equal to his annual base salary payable over the twelve-month period from his separation of service, in accordance with regular payroll practices, and (ii) have us pay directly or reimburse him for COBRA premiums if he (or his dependents) elect to receive continued healthcare coverage pursuant to COBRA until the earlier of twelve months, the date the covered dependents are no longer eligible or the date he becomes eligible to receive substantially comparable coverage from another employer.

        If either Messrs. Treadway or McClelland is terminated without cause or resigns for good reasons or we do not extend his term of employment, in either case within one year following the date of a change in control, then (i) in lieu of the amount of cash listed above, each is entitled to receive an amount in cash equal to two and a half times his annual base salary in effect as of the date of termination, plus two and a half times the greater of the average of his previous two years' bonus payments or his target bonus, and (ii) in lieu of the healthcare continuation listed above, we will continue to pay or reimburse his healthcare coverage pursuant to COBRA until the earlier of 18 months, the date the covered dependents are no longer eligible or the date he becomes eligible to receive substantially comparable coverage from another employer.

        Cause is defined in the employment agreements generally as the occurrence or existence of any of the following events: (i) the NEO's willful engagement in material mismanagement in providing services to us or our affiliates; (ii) the NEO's willful engagement in misconduct that he knew, based on facts known to him, could reasonably be expected to be materially injurious to us or our affiliates; (iii) the NEO's material breach of the employment agreement; (iv) the NEO's conviction of, or entrance into a plea bargain or settlement admitting guilt for, any felony, under the laws of the United States, any state or the District of Columbia; or (v) each NEO being the subject of any order, judicial or administrative, obtained or issued by the SEC, for any securities violation involving fraud. Good reason is defined in a similar manner to Mr. Reeves' employment agreement.

        Change in Control is defined to have the same meaning as in the Athlon Energy Inc. 2013 Incentive Award Plan, without regard to any amendments that may be adopted after the date of this offering.

        In addition, Messrs. Treadway's and McClelland's award agreements granting Class B limited partner interests also contain certain termination and change in control provisions, under which all unvested Class B limited partner interests will fully vest upon (i) a change of control, winding up of Athlon Holdings LP's affairs, dissolution or liquidation of Athlon Holdings LP, (ii) a sale of all or substantially all of the assets of Athlon Holdings LP or (iii) the partners of Athlon Holdings LP receiving distributions from Athlon Holdings LP representing a return of their invested capital plus an 8% compounded annual return.

Executive Compensation Plans

        The following are summaries of the short-term and long-term incentive compensation plans in which our NEOs may participate following the closing of the offering.

117

2013 Incentive Award Plan

        Following the closing of this offering, we anticipate granting equity and equity-based compensation awards to our NEOs and other key employees on a periodic basis to align compensation with our performance. These awards will be granted under the Athlon Energy Inc. 2013 Incentive Award Plan that we intend to adopt prior to the closing of this offering and which will be effective no later than the day prior to the completion of this offering. The material terms of the Athlon Energy Inc. 2013 Incentive Award Plan, which we refer to as the Plan, are described in more detail below.

Purpose; Eligibility and Administration

        The principal purpose of the Plan will be to attract, retain and engage selected employees, consultants and directors through the granting of equity and equity-based compensation awards.

        Our and our subsidiaries' employees, consultants and directors, including our NEOs, will be eligible to receive awards under the Plan. The Compensation Committee will administer the Plan unless our Board of Directors assumes authority for administration. The Compensation Committee will be authorized to delegate its duties and responsibilities as plan administrator to subcommittees comprised of our directors and/or officers, subject to certain limitations. Our Board of Directors will administer the Plan with respect to awards to non-employee directors.

        Subject to the express terms and conditions of the Plan, the plan administrator will have the authority to make all determinations and interpretations under the plan, prescribe all forms for use with the plan and adopt, amend and/or rescind rules for the administration of the plan. The plan administrator will also set the terms and conditions of all awards under the plan, including any vesting and vesting acceleration conditions.

Limitation on Awards and Shares Available

        Initially, the aggregate number of our shares of common stock available for issuance pursuant to awards granted under the Plan will be the sum of                 shares, subject to adjustment as described below plus an annual increase on the first day of each calendar year beginning January 1, 2014 and ending on and including the last January 1 prior to the expiration date of the Plan, equal to the least of (i)                  shares, (ii) 4% of the shares outstanding (on an as-converted basis) on the final day of the immediately preceding calendar year and (iii) such smaller number of shares as determined by the Board. Please read "—Certain Transactions." This number will also be adjusted due to the following shares becoming eligible to be used again for grants under the Plan:

•

shares subject to awards or portions of awards granted under the Plan which are forfeited, expire or lapse for any reason, or are settled for cash without the delivery of shares, to the extent of such forfeiture, expiration, lapse or cash settlement; and

•

shares that we repurchase prior to vesting so that such shares are returned to us.

        Shares granted under the Plan may be treasury shares, authorized but unissued shares, or shares purchased in the open market. The payment of cash dividends in conjunction with any outstanding awards will not be counted against the shares available for issuance under the Plan. In addition, if we or one of our subsidiaries acquires or combines with another company that has shares available for grant pursuant to a qualifying equity plan, we may use those shares (until such date as they could not have been used under such entity's plan) to grant awards pursuant to the Plan to individuals who were not providing services to us immediately prior to the acquisition or combination.

        The Plan will not provide for individual limits on awards that may be granted to any individual participant under the Plan. Rather, the amount of awards to be granted to individual participants will be determined by our Board of Directors or the Compensation Committee from time to time, as part of their compensation decision-making processes, provided, however, that the Plan will not permit

118

awards having a grant date fair value in excess of $700,000 to be granted to our non-employee directors in any year.

Awards

        The Plan provides for the grant of stock options (including non-qualified stock options, or "NQSOs," and incentive stock options, or "ISOs"), restricted stock, dividend equivalents, stock payments, restricted stock units, or "RSUs," performance awards, stock appreciation rights, or "SARs," and other equity-based and cash-based awards, or any combination thereof. Awards under the Plan will be set forth in award agreements, which will detail the terms and conditions of the awards, including any applicable vesting and payment terms and post-termination exercise limitations as well as any other consequences with respect to the awards upon a termination of the applicable eligible individual's service. Equity-based awards will generally be settled in shares of our common stock, but the plan administrator may provide for cash settlement of any award. A brief description of each award type follows.

•

Non-qualified Stock Options.  NQSOs will provide for the right to purchase shares of our common stock at a specified price which generally, except with respect to certain substitute options granted in connection with corporate transactions, will not be less than fair market value on the date of grant. NQSOs may be granted for any term specified by the plan administrator that does not exceed ten years and will usually become exercisable in one or more installments after the grant date, subject to vesting conditions which may include continued employment or service with us, satisfaction of performance targets and/or other conditions, as determined by the plan administrator.

•

Incentive Stock Options.  ISOs will be designed in a manner intended to comply with the provisions of Section 422 of the Internal Revenue Code, or the Code, and will be subject to specified restrictions contained in the Code. ISOs will have an exercise price of not less than 100% of the fair market value of the underlying shares on the date of grant (or 110% in the case of ISOs granted to certain significant stockholders), except with respect to certain substitute ISOs granted in connection with a corporate transaction. Only employees will be eligible to receive ISOs, and ISOs will not have a term of more than ten years (or five years in the case of ISOs granted to certain significant stockholders). Vesting conditions may apply to ISOs as determined by the plan administrator and may include continued employment or service with us, satisfaction of performance targets and/or other conditions.

•

Restricted Stock.  Restricted stock may be granted to any eligible individual and made subject to such restrictions as may be determined by the plan administrator. Unless the plan administrator determines otherwise, restricted stock may be forfeited for no consideration or repurchased by us if the conditions or restrictions on vesting are not met. In general, restricted stock may not be sold or otherwise transferred until restrictions are removed or expire. Recipients of restricted stock, unlike recipients of options, will have voting rights and will have the right to receive dividends, if any, prior to the time when the restrictions lapse, subject to the terms of an applicable award agreement, which may provide for dividends to be placed in escrow and not released until the restrictions are removed or expire.

•

Restricted Stock Units.  RSUs may be awarded to any eligible individual, typically without payment of consideration but subject to vesting conditions based upon continued employment or service with us, satisfaction of performance criteria and/or other conditions, all as determined by the plan administrator. Like restricted stock, RSUs generally may not be sold or otherwise transferred or hypothecated until the applicable vesting conditions are removed or expire. Unlike restricted stock, shares of stock underlying RSUs will not be issued until the RSUs vest (or later, if payment is deferred), and recipients of RSUs generally will have no voting or dividend rights with respect to such shares prior to the time when the applicable vesting conditions are satisfied.

119

•

Dividend Equivalents.  Dividend equivalents represent the per share value of the dividends, if any, paid by us, calculated with reference to the number of shares of our common stock covered by an award. Dividend equivalents may be settled in cash or shares and at such times as determined by the plan administrator.

•

Stock Payments.  Stock payments may be authorized by the plan administrator in the form of our shares or an option or other right to purchase our shares as part of a deferred compensation or other arrangement in lieu of all or any part of compensation, including bonuses, that would otherwise be payable in cash to an employee, consultant or non-employee director.

•

Stock Appreciation Rights.  SARs may be granted in connection with stock options, other awards or separately. SARs typically provide for payment to the holder based upon increases in the price of a share over a set exercise price. The exercise price of any SAR granted under the Plan generally, except with respect to certain substitute SARs granted in connection with a corporate transaction, will be at least 100% of the fair market value of the underlying shares on the date of grant. The term of a SAR may not be longer than ten years. There are no restrictions specified in the Plan on the exercise of SARs or the amount of gain realizable therefrom, although restrictions may be imposed by the plan administrator in the SAR award agreement. SARs granted under the Plan may be settled in cash or our shares, or in a combination of both, at the election of the plan administrator. Vesting conditions may apply to SARs as determined by the plan administrator and may include continued employment or service with us, satisfaction of performance goals and/or other conditions.

•

Performance Awards.  Performance awards may be granted by the plan administrator on an individual or group basis. Generally, these awards will consist of bonuses based upon attainment of specific performance targets and may be paid in cash, our shares or a combination of both. Performance awards may also include "phantom" stock awards that provide for payments based upon the value of our shares.

Certain Transactions

        The plan administrator will have broad discretion to equitably adjust the provisions of the Plan and the terms and conditions of existing and future awards, including with respect to aggregate number and type of shares subject to the Plan and awards granted pursuant to the Plan, to prevent the dilution or enlargement of intended benefits and/or facilitate necessary or desirable changes in the event of certain transactions and events affecting our shares, such as stock dividends, stock splits, mergers, acquisitions, consolidations and other corporate transactions. In the case of certain events or changes in capitalization that constitute "equity restructurings," equitable adjustments will be non-discretionary. In the event of a change in control where the acquirer does not assume or replace awards granted under the Plan, such awards may be subject to accelerated vesting so that 100% of such awards will become vested and exercisable or payable, as applicable, and will be exercisable for a period of fifteen days following notice of such event from the plan administrator and, if not exercised, will terminate upon the expiration of such fifteen-day period. The plan administrator may also provide for the acceleration, cash-out, termination, assumption, substitution or conversion of awards in the event of a change in control or certain other unusual or nonrecurring events or transactions. A "change in control" is defined in the Plan to mean (i) the acquisition by a person or group of more than 50% of the total combined voting power of our outstanding securities, (ii) during any consecutive two-year period, the replacement of a majority of our incumbent directors with directors whose election was not supported by at least two-thirds of our incumbent directors, (iii) a merger, consolidation, reorganization or business combination or the sale of substantially all of our assets after which the Apollo Funds and its affiliates cease to own at least 50% of the combined voting power in us, in each case, other than a transaction which results in our voting securities before such transaction continuing to represent or being converted into a majority of the voting securities of the surviving entity and after which no person or group owns a majority of the combined voting power of the surviving entity or (iv) our

120

liquidation or dissolution; provided, however, any event or occurrence whereby the Apollo Funds or a group consisting of our directors, executive officers or members of our management acquire voting control of us will not constitute a change in control for purposes of the Plan.

Transferability, Repricing and Participant Payments

        With limited exceptions for estate planning, domestic relations orders, certain beneficiary designations and the laws of descent and distribution, awards under the Plan are generally non-transferable prior to vesting and are exercisable only by the participant. The price per share of a stock option or SAR may not be decreased and an underwater stock option or SAR may not be replaced or cashed out without stockholder approval. With regard to tax withholding, exercise price and purchase price obligations arising in connection with awards under the Plan, the plan administrator may, in its discretion, accept cash or check, our shares that meet specified conditions, a "market sell order" (or other cashless broker-assisted transaction) or such other consideration as it deems suitable.

Amendment and Termination

        Our Board of Directors may terminate, amend or modify the Plan at any time and from time to time. However, we must generally obtain stockholder approval to increase the number of shares available under the Plan (other than in connection with certain corporate events, as described above) or to the extent required by applicable law, rule or regulation (including any applicable stock exchange rule).

Expiration Date

        The Plan will expire on, and no option or other award may be granted pursuant to the Plan after, the tenth anniversary of the date the plan was adopted by our Board of Directors. Any award that is outstanding on the expiration date of the Plan will remain in force according to the terms of the Plan and the applicable award agreement.

Awards To Be Granted Following This Offering

        Following the consummation of this offering, we expect that our Board of Directors will approve an award of restricted stock units under the Plan to certain of our key employees, including each of our NEOs. We currently expect that these awards will contain a combination of time and performance-based vesting conditions, with a three-year annual vesting schedule. However, the number of shares subject to the awards and the precise terms and conditions of the restricted stock units have not yet been finally determined or approved.

Director Compensation

        For 2012, individuals who served as members of our Board of Directors and predecessor governing bodies did not receive compensation for their services as directors.

        Following the consummation of this offering, our or our subsidiaries' officers, employees, consultants or advisors who also serve as directors will not receive additional compensation for their service as directors. Following the consummation of this offering, our directors who are not our or our subsidiaries' officers, employees, consultants or advisors or Apollo's officers or employees will receive cash and/or equity-based compensation for their services as directors.

        Although the terms of our expected director compensation program have not yet been determined, we expect such compensation may consist of the following:

•

an annual retainer of $40,000;

•

an additional annual retainer of $10,000 for service as the chair of any standing committee; and

121

•

an annual equity-based award granted under our Plan, having a value as of the grant date of approximately $150,000. Equity-based awards are expected to be subject to vesting conditions that have not yet been determined.

        Directors will also receive reimbursement for out-of-pocket expenses associated with attending such board or committee meetings and director and officer liability insurance coverage. Each director will be fully indemnified by us for actions associated with being a director to the fullest extent permitted under Delaware law.

Compensation Committee Interlocks and Insider Participation

        None of our officers or employees will be members of our Compensation Committee. None of our executive officers serve on the board of directors or compensation committee of a company that has an executive officer that serves on our Board of Directors or Compensation Committee. No member of our Board of Directors is an executive officer of a company in which one of our executive officers serves as a member of the board of directors or compensation committee of that company.

        To the extent any member of our Compensation Committee and affiliates of theirs has participated in transactions with us, a description of those transactions would be described in "Certain Relationships and Related Party Transactions."

122

CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS

Corporate Reorganization

        In connection with our corporate reorganization, we engaged in certain transactions with certain affiliates and the limited partners of Athlon Holdings LP. Please read "Corporate Reorganization" for a description of these transactions.

Capital Contributions

        Prior to our corporate reorganization, the Apollo Funds had committed approximately $400 million of capital contributions to fund our business and operations. As of March 31, 2013, we had remaining capital commitments of approximately $38.1 million from the Apollo Funds. After our corporate reorganization, the Apollo Funds have no further capital commitments.

Stockholders Agreement

        We will enter into a stockholders agreement with the Apollo Funds and certain stockholders in connection with this offering that will provide that, except as otherwise required by applicable law, if the Apollo Funds hold: (a) at least 50% of our outstanding common stock, they will have the right to designate no fewer than that number of directors that would constitute a majority of our Board of Directors; (b) at least 30% but less than 50% of our outstanding common stock, they will have the right to designate up to three director nominees; (c) at least 20% but less than 30% of our outstanding common stock, they will have the right to designate up to two director nominees; and (d) at least 10% but less than 20% of our outstanding common stock, they will have the right to designate up to one director nominee. The agreement also provides that if the size of our Board of Directors is increased or decreased at any time to other than seven directors, the Apollo Funds' nomination rights will be proportionately increased or decreased, respectively, rounded up to the nearest whole number. In addition, the agreement provides that if the Apollo Funds hold at least 30% of our outstanding common stock, we will cause any committee of our Board of Directors to include in its membership at least one of the Apollo Funds nominees, except to the extent that such membership would violate applicable securities laws or stock exchange or stock market rules.

        Under the stockholders agreement, if the Apollo Funds hold at least 33¹/3% of our outstanding common stock, they will have the right to engage in each of the following actions:

•

consult with and advise our senior management with respect to business and financial matters;

•

inspect all of our books, records, facilities and properties and receive financial and operating data with respect to our business and properties, when reasonably requested; and

•

designate a representative who may attend the meetings of our Board of Directors, receive the information given to directors and make recommendations to our Board of Directors. The representative shall have no vote on our Board of Directors.

        The stockholders agreement also provides that so long as the Apollo Funds hold at least 33¹/3% of our outstanding common stock, a majority of our Board of Directors, including a majority of the directors designated to our Board of Directors by the Apollo Funds, must approve certain of our significant business decisions before we are permitted to take action, including each of the following:

•

amending, modifying or repealing any provision of our certificate of incorporation and bylaws or similar organization documents in a manner that adversely affects the Apollo Funds or their affiliates;

123

•

issuing additional equity interests other than any (i) award under any stockholder-approved equity compensation plan, (ii) intra-company issuance among our subsidiaries and us or (iii) issuance of equity interests pursuant to the exchange agreement;

•

consolidating or merging with or into any other entity, transferring all or substantially all of our and our subsidiaries' assets, taken as a whole, to another entity or entering into or agreeing to undertake any transaction that would constitute a "Change of Control" as defined in our credit agreement or the indenture governing our senior notes;

•

disposing of any of our or any of our subsidiaries' assets with a value in excess of $100 million in any single transaction or $200 million in the aggregate in any series of transactions during a calendar year;

•

consummating any acquisition by us or any of our subsidiaries of the equity interests or assets of any other entity involving consideration in excess of $100 million in any single transaction or $200 million in the aggregate in any series of transactions during a calendar year;

•

incurring any indebtedness by us or any of our subsidiaries (including through capital leases, the issuance of debt securities or the guarantee of indebtedness of another entity) that would result in our total net indebtedness to adjusted EBITDA for the trailing twelve-month period exceeding 2.50 to 1.0;

•

terminating our Chief Executive Officer or designating a new Chief Executive Officer; and

•

changing the size of our Board of Directors.

        The stockholders agreement will also provide that the Apollo Funds, or any employee stockholder owning at least 1% of our outstanding common stock, may make one or more written demands requiring us to register the shares of our common stock owned by the Apollo Funds or the employee stockholders. In addition, any stockholder (including the Apollo Funds) will have piggyback rights entitling them to require us to register shares of our common stock owned by them in connection with any registration statements filed by us, subject to certain exceptions. We will agree to indemnify the Apollo Funds (to the extent they are selling stockholders in any such registration) against losses suffered by them in connection with any untrue or alleged untrue statement of a material fact contained in any registration statement, prospectus or preliminary prospectus or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statement therein not misleading, except insofar as the same may be caused by or contained in any information furnished in writing to us by such selling stockholder for use therein.

Transaction Fee Agreement

        We are a party to a Transaction Fee Agreement, dated August 23, 2010, which requires us to pay a fee to Apollo equal to 2% of the total equity contributed to us, as defined in the agreement, in exchange for consulting and advisory services provided by Apollo. In October 2012, Apollo assigned its rights and obligations under the Transaction Fee Agreement to one of its affiliates, Apollo Global Securities, LLC. Since our inception through March 31, 2013, we have incurred transaction fees under the Transaction Fee Agreement of approximately $7.5 million in total. Upon the consummation of this offering, we intend to terminate the Transaction Fee Agreement.

Services Agreement

        We are party to a Services Agreement, dated August 23, 2010, which requires us to compensate Apollo for consulting and advisory services equal to the higher of (i) 1.00% of earnings before interest, income taxes, depletion, depreciation, amortization and exploration expense per quarter and (ii) $62,500 per quarter (the "Advisory Fee"); provided, however, that such Advisory Fee for any

124

calendar year shall not exceed $500,000. The Services Agreement also provides for reimbursement to Apollo for any reasonable out-of-pocket expenses incurred while performing services under the Services Agreement. During the first quarter of 2013 and 2012, we incurred approximately $405,000 and $213,000, respectively, of Advisory Fees. During 2012 and 2011, we incurred approximately $493,000 and $411,000, respectively, of Advisory Fees.

        The Services Agreement provides that Apollo will provide advisory services until the earliest of (i) August 23, 2020, (ii) such time as Apollo owns in the aggregate less than 5% of the beneficial economic interest of Athlon Holdings LP and (iii) such date as is mutually agreed upon by us and Apollo. Upon the consummation of this offering, we intend to terminate the Services Agreement and, in connection with the termination, Apollo will receive approximately $2.5 million (plus any unreimbursed expenses) from us. Such payment corresponds to the present value as of the date of termination of the aggregate annual fees that would have been payable during the remainder of the term of the Services Agreement (assuming a term ending on August 23, 2020) using a discount rate of 8.0%. Under the Services Agreement, we also agreed to indemnify Apollo and its affiliates and their respective limited partners, general partners, directors, members, officers, managers, employees, agents, advisors, their directors, officers and representatives for potential losses relating to the services contemplated under the Services Agreement.

Participation of Apollo Global Securities, LLC in Senior Notes Offering and this Offering

        Apollo Global Securities, LLC is an affiliate of our sponsor the Apollo Funds and received a portion of the gross spread as an initial purchaser in our senior notes offering of approximately $500,000. Apollo Global Securities, LLC is also an underwriter in this offering and will receive a portion of the discounts and commissions paid to the underwriters in this offering. See "Underwriting (Conflicts of Interest)."

Distribution

        We used a portion of the net proceeds from the senior notes offering to make a distribution to our Class A limited partners, including the Apollo Funds and our management team. The Apollo Funds received approximately $73 million of the distribution and the remaining Class A limited partners received approximately $2 million, in the aggregate.

Exchange Agreement

        We will enter into an exchange agreement with certain members of our management team and employees that will hold New Holdings Units after the closing of this offering. Under the exchange agreement, each such holder (and certain permitted transferees thereof) may, under certain circumstances after the date of the closing of this offering (subject to the terms of the exchange agreement), exchange their New Holdings Units for shares of common stock of Athlon Energy Inc. on a one-for-one basis, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications. As a holder exchanges its New Holdings Units, Athlon Energy Inc.'s interest in Athlon Holdings LP will be correspondingly increased.

Tax Receivable Agreement

        As described under "—Exchange Agreement," the holders of New Holdings Units may (subject to the terms of the exchange agreement) exchange such units for shares of common stock of Athlon Energy Inc. on a one-for-one basis. Athlon Holdings LP (and each of its subsidiaries treated as partnerships for United States federal income tax purposes) intends to make an election under Section 754 of the Code effective for each taxable year in which an exchange of Athlon Holdings LP units for shares of common stock occurs, which may result in an adjustment to the tax basis of the

125

assets of Athlon Holdings LP at the time of an exchange. As a result of these exchanges, Athlon Energy Inc., which we refer to as the "corporate taxpayer", will become entitled to a proportionate share of the existing tax basis of the assets of Athlon Holdings LP. In addition, the purchase of New Holdings Units and subsequent exchanges are expected to result in increases in the tax basis of the assets of Athlon Holdings LP that otherwise would not have been available. Both this proportionate share and these increases in tax basis may reduce the amount of tax that the corporate taxpayer would otherwise be required to pay in the future. These increases in tax basis may also decrease gains (or increase losses) on future dispositions of certain capital assets to the extent tax basis is allocated to those capital assets. The IRS may challenge all or part of the existing tax basis, tax basis increase and increased deductions, and a court could sustain such a challenge.

        We will enter into a tax receivable agreement with certain members of our management team and employees that will hold New Holdings Units after the closing of this offering that will provide for the payment from time to time by the corporate taxpayer to such unitholders of Athlon Holdings LP of 85% of the amount of the benefits, if any, that the corporate taxpayer is deemed to realize as a result of increases in tax basis and certain other tax benefits related to exchanges of New Holdings Units pursuant to the exchange agreement, including tax benefits attributable to payments under the tax receivable agreement. These payment obligations will be obligations of the corporate taxpayer and not of Athlon Holdings LP. For purposes of the tax receivable agreement, the benefit deemed realized by the corporate taxpayer will be computed by comparing the actual income tax liability of the corporate taxpayer (calculated with certain assumptions) to the amount of such taxes that the corporate taxpayer would have been required to pay had there been no increase to the tax basis of the assets of Athlon Holdings LP as a result of the exchanges and had the corporate taxpayer not entered into the tax receivable agreement. The term of the tax receivable agreement will continue until all such tax benefits have been utilized or expired, unless the corporate taxpayer exercises its right to terminate the tax receivable agreement for an amount based on the agreed payments remaining to be made under the agreement, the corporate taxpayer breaches any of its material obligations under the tax receivable agreement or the holders of New Holdings Units elect to terminate the tax receivable agreement, in which case the corporate taxpayer's obligations will generally be accelerated. Estimating the amount of payments that may be made under the tax receivable agreement is by its nature imprecise, insofar as the calculation of amounts payable depends on a variety of factors. The actual increase in tax basis, as well as the amount and timing of any payments under the tax receivable agreement, will vary depending upon a number of factors, including:

•

the timing of exchanges—for instance, the increase in any tax deductions will vary depending on the fair value, which may fluctuate over time, of the depletable, depreciable or amortizable assets of Athlon Holdings LP at the time of each exchange;

•

the price of shares of our common stock at the time of the exchange—the increase in any tax deductions, as well as the tax basis increase in other assets, of Athlon Holdings LP is directly proportional to the price of shares of our common stock at the time of the exchange;

•

the extent to which such exchanges are taxable—if an exchange is not taxable for any reason, increased deductions will not be available; and

•

the amount and timing of our income—the corporate taxpayer will be required to pay 85% of the deemed benefits as and when deemed realized. If the corporate taxpayer does not have taxable income, the corporate taxpayer generally is not required (absent a change of control or circumstances requiring an early termination payment) to make payments under the tax receivable agreement for that taxable year because no benefit will have been actually realized. However, any tax benefits that do not result in realized benefits in a given tax year will likely generate tax attributes that may be utilized to generate benefits in previous or future tax years. The utilization of such tax attributes will result in payments under the tax receivable agreement.

126

        The step-up in basis will depend on the fair value of the New Holdings Units at conversion. Further, we do not expect to be in a tax paying position before 2019, so we cannot presently determine what the benefit or payments under the tax receivable agreement will be. In addition, there is no intent of the holders of New Holdings Units to exchange their units for shares of our common stock in the foreseeable future.

        In addition, the tax receivable agreement will provide that upon certain mergers, asset sales, other forms of business combinations or other changes of control, the corporate taxpayer's (or its successor's) obligations with respect to exchanged or acquired New Holdings Units (whether exchanged or acquired before or after such transaction) would be based on certain assumptions, including that the corporate taxpayer would have sufficient taxable income to fully utilize the deductions arising from the increased tax deductions and tax basis and other benefits related to entering into the tax receivable agreement. As a result, we could be required to make payments under the tax receivable agreement that are greater than or less than the specified percentage of the actual benefits we realize in respect of the tax attributes subject to the tax receivable agreement. Furthermore, if we elect to terminate the tax receivable agreement early, we would be required to make an immediate payment equal to the present value of the anticipated future tax benefits, which upfront payment may be made years in advance of the actual realization of such future benefits. In these situations, our obligations under the tax receivable agreement could have a substantial negative impact on our liquidity.

        Decisions made in the course of running our business, such as with respect to mergers, asset sales, other forms of business combinations or other changes in control, may influence the timing and amount of payments that are received by an exchanging or selling existing owner under the tax receivable agreement. For example, the earlier disposition of assets following an exchange or acquisition transaction will generally accelerate payments under the tax receivable agreement and increase the present value of such payments, and the disposition of assets before an exchange or acquisition transaction will increase an existing owner's tax liability without giving rise to any rights of an existing owner to receive payments under the tax receivable agreement.

        Payments will be generally due under the tax receivable agreement within a specified period of time following the filing of our tax return for the taxable year with respect to which the payment obligation arises, although interest on such payments will begin to accrue at a rate of LIBOR plus 300 basis points from the due date (without extensions) of such tax return.

        Payments under the tax receivable agreement will be based on the tax reporting positions that we will determine. Although we are not aware of any issue that would cause the IRS to challenge a tax basis increase, the corporate taxpayer will not be reimbursed for any payments previously made under the tax receivable agreement. As a result, in certain circumstances, payments could be made under the tax receivable agreement in excess of the benefits that the corporate taxpayer actually realizes in respect of the tax attributes subject to the tax receivable agreement.

Athlon Holdings LP Amended and Restated Limited Partnership Agreement

        Upon the closing of this offering, the limited partnership agreement of Athlon Holdings LP will be amended and restated to, among other things, modify Athlon Holdings LP's capital structure by replacing its different classes of interests with a single new class of units as described in "Corporate Reorganization."

        The unitholders of Athlon Holdings LP, including Athlon Energy Inc., will incur U.S. federal, state and local income taxes on their proportionate share of any taxable income of Athlon Holdings LP. Net income of Athlon Holdings LP will generally be allocated to our unitholders (including Athlon Energy Inc.) in accordance with their percentage interest in Athlon Holdings LP. Net losses of Athlon Holdings LP will generally be allocated first to the unitholders (including Athlon Energy Inc.) in accordance with their percentage interest in Athlon Holdings LP until their capital accounts are reduced to zero, and

127

then to the general partner. The partnership agreement of Athlon Holdings LP will provide for quarterly cash distributions, which we refer to as "tax distributions," to the limited partners of Athlon Holdings LP (including Athlon Energy Inc.). Generally, these tax distributions will be computed based on the estimate of the Board of Supervisors as to the projected deemed income tax liability of each limited partner with respect to the partnership interest of such limited partner. Tax distributions will be made only to the extent that cash is available to cover such distributions.

Policies and Procedures for Review of Related Party Transactions

        Pursuant to its written charter, our Audit Committee must review and approve all material related party transactions, which include any related party transactions that we would be required to disclose pursuant to Item 404 of Regulation S-K promulgated by the SEC. In determining whether to approve a related party transaction, our Audit Committee will consider a number of factors including whether the related party transaction is on terms and conditions no less favorable to us than may reasonably be expected in arm's-length transactions with unrelated parties.

128

CORPORATE REORGANIZATION

        Athlon Energy Inc. is a holding company and its sole assets are controlling equity interests in Athlon Holdings LP and its subsidiaries. Athlon Energy Inc. operates and controls all of the business and affairs and consolidates the financial results of Athlon Holdings LP and its subsidiaries. Prior to our reorganization in April 2013, the Apollo Funds, members of our management team and certain employees owned all of the Class A limited partner interests in Athlon Holdings LP and members of our management team and certain employees owned all of the Class B limited partner interests in Athlon Holdings LP. In the reorganization, the Apollo Funds entered into a number of distribution and contribution transactions pursuant to which the Apollo Funds exchanged their Class A limited partner interests in Athlon Holdings LP for common stock of Athlon Energy Inc. The remaining holders of Class A limited partner interests in Athlon Holdings LP have not exchanged their interests in the reorganization transactions. In addition, the holders of the Class B limited partner interests in Athlon Holdings LP exchanged their interests for common stock of Athlon Energy Inc. Upon closing of this offering, the limited partnership agreement of Athlon Holdings LP will be amended and restated to, among other things, modify Athlon Holdings LP's capital structure by replacing its different classes of interests with a single new class of units that we refer to as the "New Holdings Units." The members of our management team and certain employees that hold Class A limited partner interests will own New Holdings Units and will enter into an exchange agreement under which (subject to the terms of the exchange agreement) they will have the right, under certain circumstances, to exchange their New Holdings Units for shares of common stock of Athlon Energy Inc. on a one-for-one basis, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications. All other New Holdings Units will be held by Athlon Energy Inc.

        The diagrams below set forth our simplified organizational structure before and after our corporate reorganization and this offering. These charts are provided for illustrative purpose only and do not represent all legal entities affiliated with us. The ownership percentages after this offering are based on an estimated valuation of Athlon using an assumed initial public offering price of $          per share, the midpoint of the price range set forth on the cover page of this prospectus.

Pre-Reorganization Structure Before the Offering

¹

Borrowing base of $320 million as of July 12, 2013.

²

Co-Issuer of our 7³/8% senior notes due 2021.

³

Guarantors of our credit agreement and 7³/8% senior notes due 2021.

129

Post-Reorganization Structure After the Offering

¹

The Apollo Funds and the public stockholders will hold          % and          % of our shares of common stock, respectively, if the underwriters exercise in full their option to purchase additional shares of common stock from the Apollo Funds.

²

Borrowing base of $320 million as of July 12, 2013.

³

Co-Issuer of our 7³/8% senior notes due 2021.

⁴

Guarantors of our credit agreement and 7³/8% senior notes due 2021.

130

PRINCIPAL AND SELLING STOCKHOLDERS

        The following table sets forth the beneficial ownership of our common stock and New Holdings Units, after giving effect to the reorganization transactions described under "Corporate Reorganization," immediately prior to and after this offering by:

•

each entity or person known by us to beneficially own more than 5% of our outstanding common stock (assuming the exchange of all New Holdings Units for common stock);

•

each of our named executive officers;

•

each member of or nominee to our Board of Directors;

•

all of our directors, director nominees and executive officers as a group; and

•

each of the selling stockholders.

        Except as otherwise indicated, the person or entities listed below have sole voting and investment power with respect to all shares of our common stock beneficially owned by them, except to the extent this power may be shared with a spouse. All information with respect to beneficial ownership has been furnished by the respective directors, director nominees, named executive officers or 5% or more stockholders, as the case may be. Unless otherwise indicated, the address for each listed beneficial owner is 420 Throckmorton Street, Suite 1200, Fort Worth, Texas 76102.

        Upon the completion of this offering, the Apollo Funds will own, in the aggregate, approximately          % of our outstanding common stock (or approximately          % if the underwriters exercise in full their option to purchase additional shares of common stock from the Apollo Funds). As a result, we will qualify as a "controlled company" within the meaning of the corporate governance rules of the NYSE.

			Number of shares of common stock offered if the underwriters' option to purchase additional shares is exercised in full
	Common stock beneficially owned before the offering			Common stock beneficially owned after the offering (assuming no exercise of the underwriters' option to purchase additional shares)		Common stock beneficially owned after the offering (assuming the underwriters' option to purchase additional shares is exercised in full)
Name and Address of Beneficial Owner1	Number	Percentage		Number	Percentage	Number	Percentage
Principal and Selling Stockholders
Apollo Funds2
Directors and Named Executive Officers
Robert C. Reeves3
Gregory A. Beard
Sam Oh
Rakesh Wilson
Ted A. Gardner4
Nelson K. Treadway3
David B. McClelland3
Directors and executive officers as a group (12 persons)3

*

Less than 1%.

¹

The amounts and percentages of common stock beneficially owned are reported on the bases of regulations of the SEC governing the determination of beneficial ownership of securities. Under the rules of the SEC, a person is deemed to be a "beneficial owner" of a security if that person has or shares voting power, which includes the power to vote or direct the voting of such security, or investment power, which includes the power to dispose of or to direct the disposition of such security. Securities that can be so acquired are deemed to be outstanding for purposes of computing such person's ownership percentage, but not for purposes of computing any other person's percentage.

131

Under these rules, more than one person may be deemed beneficial owner of the same securities and a person may be deemed to be a beneficial owner of securities as to which such person has no economic interest. Except as otherwise indicated in these footnotes, each of the beneficial owners has, to our knowledge, sole voting and investment power with respect to the indicated shares of common stock. The amounts shown in the table are based on an estimated valuation of Athlon using an assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus).

²

The amount reported includes shares held of record by Apollo Athlon Holdings, L.P. ("Athlon Holdings") and AP Overseas VII (Athlon FC) Holdings, L.P. ("Overseas VII (Athlon FC)," together with Athlon Holdings, the "Apollo Funds"). Apollo Management VII, L.P. ("Management VII") is the manager of the Apollo Funds. AIF VII Management, LLC ("AIF VII LLC") is the general partner of Management VII. Apollo Management, L.P. ("Apollo Management") is the sole member and manager of AIF VII LLC, and Apollo Management GP, LLC ("Apollo Management GP") is the general partner of Apollo Management. Apollo Management Holdings, L.P. ("Management Holdings") is the sole member and manager of Apollo Management GP, and Apollo Management Holdings GP, LLC ("Management Holdings GP") is the general partner of Management Holdings. Leon Black, Joshua Harris and Marc Rowan are the managers, as well as executive officers, of Management Holdings GP, and as such may be deemed to have voting and dispositive control over the shares of our common stock held by the Apollo Funds. The address of the Apollo Funds is One Manhattanville Road, Suite 201, Purchase, New York 10577. The address of each of Management VII, AIF VII LLC, Apollo Management, Apollo Management GP, Management Holdings and Management Holdings GP, and Messrs. Black, Harris and Rowan, is 9 West 57th Street, 43rd Floor, New York, New York 10019.

³

Includes New Holdings Units that are exchangeable for shares of our common stock as follows: Mr. Reeves (          ), Mr. Treadway (          ), Mr. McClelland (          ) and directors and executive officers as a group (          ).

⁴

Director nominee.

132

DESCRIPTION OF CAPITAL STOCK

The following is a description of the material terms of our amended and restated certificate of incorporation and amended and restated bylaws as each will be in effect as of the closing of this offering, and of specific provisions of Delaware law. The following description is intended as a summary only and is qualified in its entirety by reference to our amended and restated certificate of incorporation, our amended and restated bylaws and the DGCL.

General

        Pursuant to our amended and restated certificate of incorporation, our capital stock will consist of 550,000,000 authorized shares, of which 500,000,000 shares, par value $0.01 per share, will be designated as "common stock" and 50,000,000 shares, par value $0.01 per share, will be designated as "preferred stock." There will be no shares of preferred stock outstanding immediately following the closing of this offering. Upon the effectiveness of our amended and restated certificate of incorporation following the closing of this offering, we will have one class of common stock.

Common Stock

        Voting Rights.    Holders of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders. Holders of common stock do not have cumulative voting rights in the election of directors.

        Dividend Rights.    Holders of common stock are entitled to receive ratably dividends if, as and when dividends are declared from time to time by our Board of Directors out of funds legally available for that purpose, after payment of dividends required to be paid on outstanding preferred stock, as described below, if any. Under Delaware law, we can only pay dividends either out of "surplus" or out of the current or the immediately preceding year's net profits. Surplus is defined as the excess, if any, at any given time, of the total assets of a corporation over its total liabilities and statutory capital. The value of a corporation's assets can be measured in a number of ways and may not necessarily equal their book value.

        Liquidation Rights.    Upon liquidation, dissolution or winding up of our affairs, whether voluntarily or involuntarily, the holders of common stock are entitled to receive ratably the assets available for distribution to the stockholders after payment of liabilities and accrued but unpaid dividends and liquidation preferences on any outstanding preferred stock.

        Other Matters.    The common stock has no preemptive, subscription or conversion rights. There are no redemption or sinking fund provisions applicable to the common stock. All outstanding shares of our common stock are fully paid and non-assessable, and the shares of our common stock offered in this offering, upon payment and delivery in accordance with the underwriting agreement, will be fully paid and non-assessable.

Preferred Stock

        Pursuant to our amended and restated certificate of incorporation, shares of preferred stock will be issuable from time to time, in one or more series, with the designations of the series, the dividend rates and whether such dividends will be cumulative or non-cumulative, the voting conversion or exchange rights of the shares of the series (if any), redemption rights, whether or not the shares of the series will be entitled to the benefit of a retirement or sinking fund, liquidation rights, the powers, preferences and relative, participation, optional or other special rights (if any), and any qualifications, limitations or restrictions thereof as our Board of Directors from time to time may adopt by resolution (and without further stockholder approval), subject to certain limitations. Each series will consist of that number of shares as will be stated and expressed in the certificate of designations providing for the

133

issuance of the stock of the series, which number may be increased or decreased from time to time by our Board of Directors. All shares of any one series of preferred stock will be identical.

Composition of Board of Directors; Election and Removal of Directors; Number of Directors

        In accordance with our amended and restated certificate of incorporation and our amended and restated bylaws, the number of directors comprising our Board of Directors will be determined from time to time by our Board of Directors, and only a majority of the Board of Directors may fix the number of directors; provided that in no event shall the total number of directors be less than three nor more than fifteen. Assuming the Apollo Funds continue to control at least 50% of our common stock, we intend to avail ourselves of the "controlled company" exception under the NYSE rules, which exempt us from certain requirements, including the requirements that we have a majority of independent directors on our Board of Directors and that we have a compensation committee and a nominating and corporate governance committee composed entirely of independent directors. We will, however, remain subject to the requirement that we have an audit committee composed entirely of independent members.

        The stockholders agreement that we will enter into in connection with this offering will provide that, except as otherwise required by applicable law, if the Apollo Funds hold: (a) at least 50% of our outstanding common stock, they will have the right to designate no fewer than that number of directors that would constitute a majority of our Board of Directors; (b) at least 30% but less than 50% of our outstanding common stock, they will have the right to designate up to three director nominees; (c) at least 20% but less than 30% of our outstanding common stock, they will have the right to designate up to two director nominees; and (d) at least 10% but less than 20% of our outstanding common stock, they will have the right to designate up to one director nominee. The agreement also provides that if the size of our Board of Directors is increased or decreased at any time to other than seven directors, Apollo's nomination rights will be proportionately increased or decreased, respectively, rounded up to the nearest whole number. In addition, the agreement provides that if the Apollo Funds hold at least 30% of our outstanding common stock, we will cause any committee of our Board of Directors to include in its membership at least one of the Apollo Funds nominees, except to the extent that such membership would violate applicable securities laws or stock exchange or stock market rules.

        Upon the closing of this offering, it is anticipated that we will have five directors. Within 90 days of our listing on the NYSE, we will appoint at least one additional director, and within one year of the date of effectiveness of the registration statement, we will appoint at least one more additional director. Our amended and restated bylaws will provide that our Board of Directors is divided into three classes of directors, with the classes to be as nearly equal in number as possible. As a result, approximately one-third of our Board of Directors will be elected at each annual meeting of stockholders, with such elections decided by plurality vote, each year. The classification of directors has the effect of making it more difficult for stockholders to change the composition of our Board of Directors. Each director is to hold office until his successor is duly elected and qualified or until his earlier death, resignation or removal. Any vacancies on our Board of Directors may be filled only by the affirmative vote of a majority of the remaining directors, although less than a quorum. Our amended and restated certificate of incorporation will provide that stockholders do not have the right to cumulative votes in the election of directors. At any meeting of our Board of Directors, except as otherwise required by law, a majority of the total number of directors then in office will constitute a quorum for all purposes. Please read "Management—Committees of the Board of Directors."

Special Meetings of Stockholders

        Our amended and restated bylaws will provide that special meetings of the stockholders may be called only by the majority of our Board of Directors or the chairman of our Board of Directors, and only proposals included in our notice to stockholders may be considered at such special meetings.

134

Certain Corporate Anti-Takeover Provisions

        Certain provisions in our amended and restated certificate of incorporation and amended and restated bylaws may be deemed to have an anti-takeover effect and may delay, deter or prevent a tender offer or takeover attempt that a stockholder might consider to be in its best interests, including attempts that might result in a premium being paid over the market price for the shares held by stockholders.

Preferred Stock

        Our amended and restated certificate of incorporation will contain provisions that permit our Board of Directors to issue, without any further vote or action by the stockholders, shares of preferred stock in one or more series and, with respect to each such series, to fix the number of shares constituting the series and the designation of the series, the dividend rates and whether such dividends will be cumulative or non-cumulative, the voting conversion or exchange rights of the shares of the series (if any), redemption rights, whether or not the shares of the series will be entitled to the benefit of a retirement or sinking fund, liquidation rights, the powers, preferences and relative, participation, optional and other special rights, if any, and any qualifications, limitations or restrictions, of the shares of such series. Please read "—Preferred Stock."

Classified Board

        Our amended and restated certificate of incorporation and amended and restated bylaws will provide that our Board of Directors is divided into three classes of directors, with the classes to be as nearly equal in number as possible, and the number of directors on our Board of Directors may be fixed only by the majority of our Board of Directors, as described above in "—Composition of Board of Directors; Election and Removal of Directors; Number of Directors."

Removal of Directors; Vacancies

        At any time at least 33¹/3% of the voting power of all our shares is owned by the Apollo Funds and the Apollo Funds cast their votes associated with such shares in favor of the proposed action, our stockholders will be able to remove directors only by the affirmative vote of the holders of a majority of the voting power entitled to vote for the election of directors. At any other time, our stockholders will be able to remove directors only for cause and only by the affirmative vote of the holders of at least 66²/3% of the voting power entitled to vote for the election of directors. Vacancies on our Board of Directors may be filled only by a majority of our Board of Directors, although less than a quorum.

No Cumulative Voting

        Our amended and restated certificate of incorporation will provide that stockholders do not have the right to cumulative votes in the election of directors. Cumulative voting rights would have been available to the holders of our common stock if our amended and restated certificate of incorporation had not specifically provided that cumulative voting was not available.

No Stockholder Action by Written Consent; Calling of Special Meetings of Stockholders

        Our amended and restated certificate of incorporation will not permit stockholder action without a meeting by consent if less than a majority of the voting power of all our shares is owned by the Apollo Funds. So long as the Apollo Funds own a majority of the voting power of all our shares, stockholder action without a meeting by consent is permitted without a meeting, without prior notice and without a vote, if a consent or consents in writing, setting forth the action so taken, is signed by stockholders having not less than the minimum number of votes that would be necessary to authorize or take the action at a meeting at which all our shares were present and voted. Our amended and restated bylaws

135

will also provide that special meetings of the stockholders may be called only by a majority of our Board of Directors or the chairman of our Board of Directors, and only proposals included in the company's notice may be considered at such special meetings.

Advance Notice Requirements for Stockholders Proposals and Director Nominations

        Our amended and restated bylaws will provide that stockholders seeking to bring business before an annual meeting of stockholders, or to nominate candidates for election as directors at an annual meeting of stockholders, must provide timely notice thereof in writing. To be timely, a stockholder's notice generally will have to be delivered to and received at our principal executive offices not less than 60 days nor more than 120 days prior to the first anniversary of the preceding year's annual meeting; provided, that in the event that the date of such meeting is advanced more than 30 days prior to, or delayed by more than 30 days after, the anniversary of the preceding year's annual meeting of our stockholders, a stockholder's notice to be timely will have to be so delivered not earlier than the close of business on the 120th day prior to such meeting and not later than the close of business on the later of the 90th day prior to such meeting or, if the first public announcement of the date of such annual meeting is less than 100 days prior to such meeting, the tenth day following the day on which public announcement of the date of such meeting is first made. Our amended and restated bylaws will also specify certain requirements as to the form and content of a stockholder's notice. These provisions may preclude stockholders from bringing matters before an annual meeting of stockholders or from making nominations for directors at an annual meeting of stockholders.

        All the foregoing proposed provisions of our amended and restated certificate of incorporation and amended and restated bylaws could discourage potential acquisition proposals and could delay or prevent a change in control. These provisions are intended to enhance the likelihood of continuity and stability in the composition of our Board of Directors and in the policies formulated by our Board of Directors and to discourage certain types of transactions that may involve an actual or threatened change of control. These same provisions may delay, deter or prevent a tender offer or takeover attempt that a stockholder might consider to be in its best interest. In addition, such provisions could have the effect of discouraging others from making tender offers for our shares and, as a consequence, they also may inhibit fluctuations in the market price of our common stock that could result from actual or rumored takeover attempts. Such provisions also may have the effect of preventing changes in our management.

Delaware Anti-Takeover Law

        We have elected to be exempt from the restrictions imposed under Section 203 of the DGCL. Section 203 of the DGCL provides that, subject to exception specified therein, an "interested stockholder" of a Delaware corporation shall not engage in any "business combination," including general mergers or consolidations or acquisitions of additional shares of the corporation, with the corporation for a three-year period following the time that such stockholder becomes an interested stockholder unless:

•

prior to such time, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

•

upon consummation of the transaction which resulted in the stockholder becoming an "interested stockholder," the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced (excluding specified shares); or

•

on or subsequent to such time, the business combination is approved by the board of directors of the corporation and authorized at an annual or special meeting of stockholders, and not by

136

written consent, by the affirmative vote of at least 66²/3% of the outstanding voting stock not owned by the interested stockholder.

        Under Section 203, the restrictions described above also do not apply to specified business combinations proposed by an interested stockholder following the announcement or notification of one of specified transactions involving the corporation and a person who had not been an interested stockholder during the previous three years or who became an interested stockholder with the approval of a majority of the corporation's directors, if such transaction is approved or not opposed by a majority of the directors who were directors prior to any person becoming an interested stockholder during the previous three years or were recommended for election or elected to succeed such directors by a majority of such directors.

        Except as otherwise specified in Section 203, an "interested stockholder" is defined to include:

•

any person that is the owner of 15% or more of the outstanding voting stock of the corporation, or is an affiliate or associate of the corporation and was the owner of 15% or more of the outstanding voting stock of the corporation at any time within three years immediately prior to the date of determination; and

•

the affiliates and associates of any such person.

        Under some circumstances, Section 203 makes it more difficult for a person who is an interested stockholder to effect various business combinations with us for a three-year period.

Corporate Opportunity

        Under our amended and restated certificate of incorporation, to the extent permitted by law:

•

any director or officer of Athlon who is also an officer, director, employee, managing director or other affiliate of Apollo (each a "Covered Apollo Person") has the right to, and has no duty to abstain from, exercising such right to, conduct business with any business that is competitive or in the same line of business as Athlon, do business with any of Athlon's clients, customers, vendors or lessors, or make investments in the kind of property in which Athlon may make investments;

•

if a Covered Apollo Person or any of its officers, partners, directors or employees acquire knowledge of a potential transaction that could be a corporate opportunity, he has no duty to offer such corporate opportunity to Athlon;

•

Athlon has renounced any interest or expectancy in, or in being offered an opportunity to participate in, such corporate opportunities; and

•

in the event that any of Athlon's directors and officers who is also a Covered Apollo Person acquires knowledge of a corporate opportunity or is offered a corporate opportunity, provided that this knowledge was not acquired solely in such person's capacity as Athlon's director or officer and such person acted in good faith, then such person will be deemed to have fully satisfied such person's fiduciary duty and will not be liable to us or our stockholders if any of the Covered Apollo Persons pursues or acquires such corporate opportunity or if such person did not present the corporate opportunity to Athlon.

Amendment of Our Certificate of Incorporation

        Our amended and restated certificate of incorporation will provide that at any time the Apollo Funds control at least 33¹/3% of the voting power of our outstanding common stock, the amended and restated certificate of incorporation can be amended with the affirmative vote of a majority of the outstanding stock entitled to vote thereon or by the vote of a majority of our Board of Directors, so

137

long as the Apollo Funds vote in favor of such amendment. At any other time our amended and restated certificate of incorporation will provide that the amended and restated certificate of incorporation can be amended by the affirmative vote of at least 66²/3% of the outstanding stock entitled to vote thereon or by the vote of a majority of our Board of Directors.

Amendment of Our Bylaws

        Our amended and restated certificate of incorporation will provide that at any time the Apollo Funds control at least 33¹/3% of the voting power of our outstanding common stock, the amended and restated bylaws can be amended with the affirmative vote of a majority of the outstanding stock entitled to vote thereon, so long as the Apollo Funds vote in favor of such amendment, or by the vote of a majority of our Board of Directors. At any other time our amended and restated certificate of incorporation will provide that the amended and restated bylaws can be amended by the affirmative vote of at least 66²/3% of the outstanding stock entitled to vote thereon or by the vote of a majority of our Board of Directors.

Limitation of Liability and Indemnification

        Our amended and restated certificate of incorporation will limit the liability of our directors to the maximum extent permitted by Delaware law. Delaware law provides that directors will not be personally liable for monetary damages for breach of their fiduciary duties as directors, except with respect to liability:

•

for any breach of the director's duty of loyalty to us or our stockholders;

•

for acts or omissions not in good faith or that involve intentional misconduct or a knowing violation of law;

•

for any unlawful payments of dividends or unlawful stock repurchases or redemption as provided in Section 174 of the DGCL; or

•

for any transaction from which the director derived any improper personal benefit.

        However, if the DGCL is amended to authorize corporate action further eliminating or limiting the personal liability of directors, then the liability of our directors will be eliminated or limited to the fullest extent permitted by the DGCL, as so amended. The modification or repeal of this provision of our amended and restated certificate of incorporation will not adversely affect any right or protection of a director existing at the time of such modification or repeal.

        Our amended and restated certificate of incorporation and amended and restated bylaws will provide that we will, to the fullest extent from time to time permitted by law, indemnify our directors and officers against all liabilities and expenses in any suit or proceeding, arising out of their status as an officer or director or their activities in these capacities. We will also indemnify any person who, at our request, is or was serving as a director, officer, trustee, employee or agent of another corporation, partnership, joint venture, trust or other enterprise. We may, by action of our Board of Directors, provide indemnification to our employees and agents within the same scope and effect as the foregoing indemnification of directors and officers. In addition, we intend to enter into separate indemnification agreements with each of our directors and executive officers, which may be broader than the specific indemnification provisions contained in the DGCL. These indemnification agreements may require us, among other things, to indemnify our directors and officers against liabilities that may arise by reason of their status or service as directors or officers, other than liabilities arising from willful misconduct.

        The right to be indemnified will include the right of an officer or a director to be paid expenses, including attorneys' fees, in advance of the final disposition of any proceeding, provided that, if

138

required by law, we receive an undertaking to repay such amount if it will be determined that he or she is not entitled to be indemnified.

        Our Board of Directors may take such action as it deems necessary to carry out these indemnification provisions, including adopting procedures for determining and enforcing indemnification rights and purchasing insurance policies. Our Board of Directors may also adopt bylaws, resolutions or contracts implementing indemnification arrangements as may be permitted by law. Neither the amendment nor the repeal of these indemnification provisions, nor the adoption of any provision of our amended and restated certificate of incorporation inconsistent with these indemnification provisions, will eliminate or reduce any rights to indemnification relating to such person's status or any activities prior to such amendment, repeal or adoption.

        We believe these provisions will assist in attracting and retaining qualified individuals to serve as directors and officers.

Transfer Agent and Registrar

        The transfer agent and registrar for our common stock will be Computershare Trust Company, N.A.

Listing

        We have been approved to list our common stock on the NYSE under the symbol "ATHL."

139

SHARES ELIGIBLE FOR FUTURE SALE

        Prior to this offering, there has been no public market for our common stock, and no predictions can be made about the effect, if any, that market sales of shares of our common stock or the availability of such shares for sale will have on the market price prevailing from time to time. Nevertheless, the actual sale of, or the perceived potential for the sale of, our common stock in the public market may have an adverse effect on the market price for our common stock and could impair our ability to raise capital through future sales of our securities. Please read "Risk Factors—Risks Related to this Offering and Our Common Stock—Future sales of our common stock, or the perception that such future sales may occur, may cause our stock price to decline."

Sales of Restricted Shares

        Upon the closing of this offering, we will have              outstanding shares of common stock. Of these shares, all of the                shares of common stock to be sold in this offering will be freely tradable without restriction or further registration under the Securities Act, unless the shares are held by any of our "affiliates" as such term is defined in Rule 144 of the Securities Act. All remaining shares of common stock held by existing stockholders will be deemed "restricted securities" as such term is defined under Rule 144. The restricted securities were issued and sold by us in private transactions and are eligible for public sale only if registered under the Securities Act or if they qualify for an exemption from registration under Rule 144 or Rule 701 under the Securities Act, which rules are summarized below.

        As a result of the lock-up agreements described below and the provisions of Rule 144 and Rule 701 under the Securities Act,                shares of our common stock held by the Apollo Funds (assuming the underwriters do not exercise their option to purchase additional shares of common stock from the Apollo Funds) and our directors and executive officers will be available for sale in the public market upon the expiration of the lock-up agreements, beginning 180 days after the date of this prospectus (subject to extension) and when permitted under Rule 144 or Rule 701. In addition,               shares of our common stock will not be subject to a lock-up agreement.

Rule 144

        In general, under Rule 144, a person (or persons whose shares are aggregated) who is not deemed to have been an affiliate of ours at any time during the three months preceding a sale, and who has beneficially owned restricted securities within the meaning of Rule 144 for a least six months (including any period of consecutive ownership of preceding non-affiliated holders) would be entitled to sell those shares, subject only to the availability of current public information about us. A non-affiliated person who has beneficially owned restricted securities within the meaning of Rule 144 for at least one year would be entitled to sell those shares without regard to the provisions of Rule 144.

        In connection with our reorganization transactions, we exchanged Class B limited partner interests in Athlon Holdings LP held by members of our management team and certain employees for               shares of our common stock. Such shares are expected to be eligible for resale by the holders thereof 90 days following the closing of this offering, subject to the lock-up agreements discussed below.

        A person (or persons whose shares are aggregated) who is deemed to be an affiliate of ours and who has beneficially owned restricted securities within the meaning of Rule 144 for at least six months would be entitled to sell within any three-month period a number of shares that does not exceed the greater of 1% of the then outstanding shares of our common stock or the average weekly trading volume of our common stock reported through the NYSE during the four calendar weeks preceding the filing of notice of the sale. Such sales are also subject to certain manner of sale provisions, notice requirements and the availability of current public information about us.

140

Rule 701

        In general, under Rule 701, any of our employees, directors, officers, consultants or advisors who purchases shares from us in connection with a compensatory stock or option plan or other written agreement before the effective date of this offering is entitled to sell such shares 90 days after the effective date of this offering in reliance on Rule 144, without having to comply with the holding period requirement of Rule 144 and, in the case of non-affiliates, without having to comply with the public information, volume limitation or notice filing provisions of Rule 144. The SEC has indicated that Rule 701 will apply to typical stock options granted by an issuer before it becomes subject to the reporting requirements of the Exchange Act, along with the shares acquired upon exercise of such options, including exercises after the date of this prospectus.

Stock Issued Under Employee Plans

        We intend to file a registration statement on Form S-8 under the Securities Act to register                shares of common stock initially reserved for issuance under the Athlon Energy Inc. 2013 Incentive Award Plan that we plan to adopt prior to the completion of this offering. This registration statement is expected to be filed following the effective date of the registration statement of which this prospectus forms a part and will be effective upon filing. Accordingly, shares registered under such registration statement will be available for sale in the open market following the effective date, unless such shares are subject to vesting restrictions with us, Rule 144 restrictions applicable to our affiliates or the lock-up restrictions described below.

Registration Rights

        We have granted the Apollo Funds and certain members of our management team that hold New Holdings Units registration rights, in each case, with respect to an aggregate of               shares of common stock beneficially owned by them. Please read "Certain Relationships and Related Party Transactions—Stockholders Agreement" for more detail regarding these registration rights.

Exchange of New Holdings Units into Shares of Common Stock

        We will enter into an exchange agreement with certain members of our management team and employees that will hold an aggregate of               New Holdings Units after the closing of this offering. Under the exchange agreement, each such holder (and certain permitted transferees thereof) may, under certain circumstances after the first anniversary of the closing of this offering, exchange their New Holdings Units for shares of common stock of Athlon Energy Inc. on a one-for-one basis, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications. A holder that receives shares of our common stock upon exchange of its New Holdings Units will be eligible to sell its shares subject to Rule 144.

Lock-Up Agreements

        We, the Apollo Funds and each of our directors and executive officers have agreed that, subject to certain exceptions, without the prior written consent of Citigroup Global Markets Inc., we and they will not, directly or indirectly, for a period of 180 days after the date of the offering, offer, pledge, sell, contract to sell or otherwise transfer or dispose of any shares of our common stock (other than the shares sold by us and, if applicable, the Apollo Funds in this offering) or any other securities convertible into or exercisable or exchangeable for our common stock. For additional information, please read "Underwriting (Conflicts of Interest)."

141

MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS

        The following discussion is a summary of the material U.S. federal income tax consequences to non-U.S. holders (as defined below) of the purchase, ownership and disposition of our common stock issued pursuant to this offering, but does not purport to be a complete analysis of all potential tax effects. The effects of other U.S. federal tax laws, such as estate and gift tax laws, and any applicable state, local or foreign tax laws are not discussed. This discussion is based on the Internal Revenue Code of 1986, as amended (the "Code"), Treasury Regulations promulgated thereunder, judicial decisions and published rulings and administrative pronouncements of the IRS in effect as of the date of this offering. These authorities may change or be subject to differing interpretations. Any such change may be applied retroactively in a manner that could adversely affect a non-U.S. holder of our common stock. We have not sought and will not seek any rulings from the IRS regarding the matters discussed below. There can be no assurance the IRS or a court will not take a contrary position regarding the tax consequences of the purchase, ownership and disposition of our common stock.

        This discussion is limited to non-U.S. holders that hold our common stock as a "capital asset" within the meaning of Section 1221 of the Code (property held for investment). This discussion does not address all U.S. federal income tax consequences relevant to a non-U.S. holder's particular circumstances, including the impact of the unearned income Medicare contribution tax. In addition, it does not address consequences relevant to non-U.S. holders subject to particular rules, including, without limitation:

•

U.S. expatriates and certain former citizens or long-term residents of the United States;

•

persons subject to the alternative minimum tax;

•

persons holding our common stock as part of a hedge, straddle or other risk reduction strategy or as part of a conversion transaction or other integrated investment;

•

banks, insurance companies and other financial institutions;

•

real estate investment trusts or regulated investment companies;

•

brokers, dealers or traders in securities;

•

"controlled foreign corporations," "passive foreign investment companies" and corporations that accumulate earnings to avoid U.S. federal income tax;

•

S corporations, partnerships or other entities or arrangements treated as partnerships for U.S. federal income tax purposes;

•

tax-exempt organizations or governmental organizations;

•

persons deemed to sell our common stock under the constructive sale provisions of the Code;

•

persons who hold or receive our common stock pursuant to the exercise of any employee stock option or otherwise as compensation; and

•

tax-qualified retirement plans.

        If a partnership (or other entity treated as a partnership for U.S. federal income tax purposes) holds our common stock, the tax treatment of a partner in the partnership will depend on the status of the partner, the activities of the partnership and certain determinations made at the partner level. Accordingly, partnerships holding our common stock and the partners in such partnerships should consult their tax advisors regarding the U.S. federal income tax consequences to them.

THIS DISCUSSION IS FOR INFORMATION PURPOSES ONLY AND IS NOT INTENDED AS TAX ADVICE. INVESTORS SHOULD CONSULT THEIR TAX ADVISORS WITH RESPECT TO THE APPLICATION OF THE U.S. FEDERAL INCOME TAX LAWS TO THEIR PARTICULAR

142

SITUATIONS AS WELL AS ANY TAX CONSEQUENCES OF THE PURCHASE, OWNERSHIP AND DISPOSITION OF OUR COMMON STOCK ARISING UNDER THE U.S. FEDERAL ESTATE OR GIFT TAX LAWS OR UNDER THE LAWS OF ANY STATE, LOCAL OR NON-U.S. TAXING JURISDICTION OR UNDER ANY APPLICABLE INCOME TAX TREATY.

Definition of a Non-U.S. Holder

        For purposes of this discussion, a "non-U.S. holder" is any beneficial owner of our common stock that is neither a "U.S. person" nor a partnership for United States federal income tax purposes. A U.S. person is any of the following:

•

an individual who is a citizen or resident of the United States;

•

a corporation (or other entity taxable as a corporation for U.S. federal income tax purposes) created or organized under the laws of the United States, any state thereof, or the District of Columbia;

•

an estate, the income of which is subject to U.S. federal income tax regardless of its source; or

•

a trust that (1) is subject to the primary supervision of a U.S. court and the control of one or more United States persons (within the meaning of Section 7701(a)(30) of the Code) or (2) has made a valid election under applicable Treasury Regulations to continue to be treated as a United States person.

Distributions

        We do not anticipate declaring or paying dividends to holders of our common stock in the foreseeable future. However, if we make distributions on our common stock, such distributions of cash or property on our common stock will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. Amounts not treated as dividends for U.S. federal income tax purposes will constitute a return of capital and first be applied against and reduce a non-U.S. holder's adjusted tax basis in its common stock, but not below zero. Any excess will be treated as capital gain and will be treated as described below in the section relating to the sale or disposition of our common stock.

        Subject to the discussion below on backup withholding and foreign accounts, dividends paid to a non-U.S. holder of our common stock that are not effectively connected with the non-U.S. holder's conduct of a trade or business within the United States will be subject to U.S. federal withholding tax at a rate of 30% of the gross amount of the dividends (or such lower rate specified by an applicable income tax treaty).

        Non-U.S. holders may be entitled to a reduction in or an exemption from withholding on dividends as a result of either (a) an applicable income tax treaty or (b) the non-U.S. holder holding our common stock in connection with the conduct of a trade or business within the United States and dividends being paid in connection with that trade or business. To claim such a reduction in or exemption from withholding, the non-U.S. holder must provide the applicable withholding agent with a properly executed (a) IRS Form W-8BEN claiming an exemption from or reduction of the withholding tax under the benefit of an income tax treaty between the United States and the country in which the non-U.S. holder resides or is established, or (b) IRS Form W-8ECI stating that the dividends are not subject to withholding tax because they are effectively connected with the conduct by the non-U.S. holder of a trade or business within the United States, as may be applicable. These certifications must be provided to the applicable withholding agent prior to the payment of dividends and must be updated periodically. Non-U.S. holders that do not timely provide the applicable withholding agent with the required certification, but that qualify for a reduced rate under an applicable income tax treaty, may

143

obtain a refund of any excess amounts withheld under these rules by timely filing an appropriate claim for refund with the IRS.

        Subject to the discussion below on backup withholding and foreign accounts, if dividends paid to a non-U.S. holder are effectively connected with the non-U.S. holder's conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, the non-U.S. holder maintains a permanent establishment in the United States to which such dividends are attributable), then, although exempt from U.S. federal withholding tax (provided the non-U.S. holder provides appropriate certification, as described above), the non-U.S. holder will be subject to U.S. federal income tax on such dividends on a net income basis at the regular graduated U.S. federal income tax rates. In addition, a non-U.S. holder that is a corporation may be subject to a branch profits tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) on its effectively connected earnings and profits for the taxable year that are attributable to such dividends (and, if required by an applicable income tax treaty, that are attributable to a permanent establishment maintained by the corporate non-U.S. holder in the United States), as adjusted for certain items. Non-U.S. holders should consult their tax advisors regarding their entitlement to benefits under any applicable income tax treaty.

Sale or Other Taxable Disposition

        Subject to the discussions below on backup withholding and foreign accounts, a non-U.S. holder will not be subject to U.S. federal income tax on any gain realized upon the sale or other disposition of our common stock unless:

•

the gain is effectively connected with the non-U.S. holder's conduct of a trade or business within the United States (and, if required by an applicable income tax treaty, the non-U.S. holder maintains a permanent establishment in the United States to which such gain is attributable);

•

the non-U.S. holder is a nonresident alien individual present in the United States for 183 days or more during the taxable year of the disposition and certain other requirements are met; or

•

our common stock constitutes a U.S. real property interest by reason of our status as a U.S. real property holding corporation (a "USRPHC") for U.S. federal income tax purposes.

        Gain described in the first bullet point above will generally be subject to U.S. federal income tax on a net income basis at the regular graduated U.S. federal income tax rates. A non-U.S. holder that is a foreign corporation also may be subject to a branch profits tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) of a portion of its effectively connected earnings and profits for the taxable year, as adjusted for certain items.

        A non-U.S. holder described in the second bullet point above will be subject to U.S. federal income tax at a rate of 30% (or such lower rate specified by an applicable income tax treaty) on any gain derived from the disposition, which may be offset by certain U.S. source capital losses of the non-U.S. holder (even though the individual is not considered a resident of the United States) provided the non-U.S. holder has timely filed U.S. federal income tax returns with respect to such losses.

        With respect to the third bullet point above, we believe that we currently are, and expect to remain for the foreseeable future, a USRPHC for U.S. federal income tax purposes. However, so long as our common stock is "regularly traded on an established securities market," a non-U.S. holder will be subject to U.S. federal net income tax on a disposition of our common stock only if the non-U.S. holder actually or constructively holds or held (at any time during the shorter of the five-year period preceding the date of disposition or the holder's holding period) more than 5% of our common stock. If our common stock is not considered to be so traded, all non-U.S. holders would be subject to U.S. federal net income tax on disposition of our common stock and a 10% withholding tax would apply to the gross proceeds from the sale of our common stock by a non-U.S. holder.

144

        Non-U.S. holders should consult their tax advisors regarding potentially applicable income tax treaties that may provide for different rules.

Information Reporting and Backup Withholding

        A non-U.S. holder will not be subject to backup withholding with respect to payments of dividends on our common stock we make to the non-U.S. holder, provided the applicable withholding agent does not have actual knowledge or reason to know such holder is a United States person and the holder certifies its non-U.S. status, such as by providing a valid IRS Form W-8BEN or W-8ECI, or other applicable certification. However, information returns will be filed with the IRS in connection with any dividends on our common stock paid to the non-U.S. holder, regardless of whether any tax was actually withheld. Copies of these information returns may also be made available under the provisions of a specific treaty or agreement to the tax authorities of the country in which the non-U.S. holder resides or is established.

        Information reporting and backup withholding may apply to the proceeds of a sale of our common stock within the United States, and information reporting may (although backup withholding generally will not) apply to the proceeds of a sale of our common stock outside the United States conducted through certain U.S.-related financial intermediaries, in each case, unless the beneficial owner certifies under penalty of perjury that it is a non-U.S. holder on IRS Form W-8BEN or other applicable form (and the payor does not have actual knowledge or reason to know that the beneficial owner is a United States person) or such owner otherwise establishes an exemption.

        Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a non-U.S. holder's U.S. federal income tax liability, provided the required information is timely furnished to the IRS.

Additional Withholding Tax on Payments Made to Foreign Accounts

        Withholding taxes may be imposed under the Foreign Account Tax Compliance Act ("FATCA") on certain types of payments made to non-U.S. financial institutions and certain other non-U.S. entities. Specifically, a 30% withholding tax may be imposed on dividends on, or gross proceeds from the sale or other disposition of, our common stock paid to a "foreign financial institution" or a "non-financial foreign entity" (each as defined in the Code), unless (1) the foreign financial institution undertakes certain diligence and reporting obligations, (2) the non-financial foreign entity either certifies it does not have any "substantial United States owners" (as defined in the Code) or furnishes identifying information regarding each substantial United States owner or (3) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules. If the payee is a foreign financial institution and is subject to the diligence and reporting requirements in (1) above, it must enter into an agreement with the U.S. Department of the Treasury requiring, among other things, that it undertake to identify accounts held by certain "specified United States persons" or "United States-owned foreign entities" (each as defined in the Code), annually report certain information about such accounts and withhold 30% on payments to non-compliant foreign financial institutions and certain other account holders. Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States governing FATCA may be subject to different rules.

        Under the applicable Treasury Regulations, withholding under FATCA generally will apply to payments of dividends on our common stock made on or after January 1, 2014 and to payments of gross proceeds from the sale or other disposition of such stock on or after January 1, 2017.

        Prospective investors should consult their tax advisors regarding the potential application of withholding under FATCA to their investment in our common stock.

145

UNDERWRITING (CONFLICTS OF INTEREST)

        Citigroup Global Markets Inc. is acting as sole book-running manager of the offering and as representative of the underwriters named below. Subject to the terms and conditions stated in the underwriting agreement dated the date of this prospectus, each underwriter named below has severally agreed to purchase, and we have agreed to sell to that underwriter, the number of shares set forth opposite the underwriter's name.

Underwriter	Number of Shares
Citigroup Global Markets Inc.
Total

        The underwriting agreement provides that the obligations of the underwriters to purchase the shares included in this offering are subject to approval of legal matters by counsel and to other conditions. The underwriters are obligated to purchase all the shares (other than those covered by the underwriters' option to purchase additional shares described below) if they purchase any of the shares.

        Shares sold by the underwriters to the public will initially be offered at the initial public offering price set forth on the cover of this prospectus. Any shares sold by the underwriters to securities dealers may be sold at a discount from the initial public offering price not to exceed $            per share. After the shares are released for sale to the public, if all the shares are not sold at the initial offering price following a bona fide effort to do so, the underwriters may change the offering price and the other selling terms. The representative has advised us that the underwriters do not intend to make sales to discretionary accounts.

        If the underwriters sell more shares than the total number set forth in the table above, the Apollo Funds have granted to the underwriters an option, exercisable for 30 days from the date of this prospectus, to purchase up to              additional shares at the public offering price less the underwriting discount. The underwriters may exercise the option solely for the purpose of covering over-allotments, if any, in connection with this offering. To the extent the option is exercised, each underwriter must purchase a number of additional shares approximately proportionate to that underwriter's initial purchase commitment. Any shares issued or sold under the option will be issued and sold on the same terms and conditions as the other shares that are the subject of this offering.

        We, our officers and directors and the Apollo Funds have agreed that, for a period of 180 days from the date of this prospectus, we and they will not, without the prior written consent of Citigroup, dispose of or hedge any shares or any securities convertible into or exchangeable for our common stock. Citigroup in its sole discretion may release any of the securities subject to these lock-up agreements at any time which, in the case of officers and directors, shall be with notice.

        Prior to this offering, there has been no public market for our shares. Consequently, the initial public offering price for the shares was determined by negotiations among us, the Apollo Funds as selling stockholders, and the representatives. Among the factors considered in determining the initial public offering price were our results of operations, our current financial condition, our future prospects, our markets, the economic conditions in and future prospects for the industry in which we compete, our management and currently prevailing general conditions in the equity securities markets, including current market valuations of publicly traded companies considered comparable to our

146

company. We cannot assure you, however, that the price at which the shares will sell in the public market after this offering will not be lower than the initial public offering price or that an active trading market in our shares will develop and continue after this offering.

        We have been approved to list our shares on the NYSE under the symbol "ATHL."

        The following table shows the underwriting discounts and commissions that we and the Apollo Funds as selling stockholders are to pay to the underwriters in connection with this offering. These amounts are shown assuming both no exercise and full exercise of the underwriters' option to purchase additional shares.

	Paid by Athlon		Paid by Apollo Funds
	No Exercise	Full Exercise	No Exercise	Full Exercise
Per share	$	$	$	$
Total	$	$	$	$

        We estimate that our portion of the total expenses of this offering, excluding underwriting discounts and commissions, will be approximately $5.0 million.

        In connection with the offering, the underwriters may purchase and sell shares in the open market. Purchases and sales in the open market may include short sales, purchases to cover short positions, which may include purchases pursuant to the underwriters' option to purchase additional shares, and stabilizing purchases.

•

Short sales involve secondary market sales by the underwriters of a greater number of shares than they are required to purchase in the offering.

•

"Covered" short sales are sales of shares in an amount up to the number of shares represented by the underwriters' option to purchase additional shares.

•

"Naked" short sales are sales of shares in an amount in excess of the number of shares represented by the underwriters' option to purchase additional shares.

•

Covering transactions involve purchases of shares either pursuant to the underwriters' option to purchase additional shares or in the open market in order to cover short positions.

•

To close a naked short position, the underwriters must purchase shares in the open market. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of the shares in the open market after pricing that could adversely affect investors who purchase in the offering.

•

To close a covered short position, the underwriters must purchase shares in the open market or must exercise the underwriters' option to purchase additional shares. In determining the source of shares to close the covered short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market as compared to the price at which they may purchase shares through the underwriters' option to purchase additional shares.

•

Stabilizing transactions involve bids to purchase shares so long as the stabilizing bids do not exceed a specified maximum.

        Purchases to cover short positions and stabilizing purchases, as well as other purchases by the underwriters for their own accounts, may have the effect of preventing or retarding a decline in the market price of the shares. They may also cause the price of the shares to be higher than the price that would otherwise exist in the open market in the absence of these transactions. The underwriters may conduct these transactions on the NYSE, in the over-the-counter market or otherwise. If the underwriters commence any of these transactions, they may discontinue them at any time.

147

Conflicts of Interest

        The underwriters are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, principal investment, hedging, financing and brokerage activities. The underwriters and their respective affiliates have in the past performed commercial banking, investment banking and advisory services for us from time to time for which they have received customary fees and reimbursement of expenses and may, from time to time, engage in transactions with and perform services for us in the ordinary course of their business for which they may receive customary fees and reimbursement of expenses. In the ordinary course of their various business activities, the underwriters and their respective affiliates, officers, directors and employees may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (which may include bank loans and/or credit default swaps) for their own account and for the accounts of their customers and may at any time hold long and short positions in such securities and instruments. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates including the Apollo Funds.

        In addition, affiliates of certain of the underwriters are lenders under our credit agreement and/or are holders of our senior notes. Certain of the underwriters or their affiliates that have a lending relationship with us routinely hedge their credit exposure to us consistent with their customary risk management policies. A typical such hedging strategy would include these underwriters or their affiliates hedging such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities. Certain of the underwriters or their affiliates were initial purchasers in our senior notes offering and received customary fees and reimbursement of expenses. In connection therewith, Apollo Global Securities, LLC, an affiliate of our sponsor, was an initial purchaser in our senior notes offering and received a portion of the gross spread of approximately $500,000. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

        Apollo Global Securities, LLC is an affiliate of our sponsor, the Apollo Funds. Since the Apollo Funds beneficially owns more than 10% of our outstanding common stock, a "conflict of interest" is deemed to exist under Rule 5121(f)(5)(B) of the Conduct Rules of the Financial Industry Regulatory Authority, or FINRA. In addition, if the Apollo Funds sell shares of common stock in this offering, the Apollo Funds, as selling stockholders, will likely receive more than 5% of the net proceeds of this offering and a "conflict of interest" will also exist under Rule 5121(f)(5)(c)(ii). Accordingly, this offering will be made in compliance with the applicable provisions of Rule 5121. Since Apollo is not primarily responsible for managing this offering, the appointment of a "qualified independent underwriter" is not required pursuant to Rule 5121(a)(1). As such, any underwriter that has a conflict of interest pursuant to Rule 5121 will not confirm sales to accounts in which it exercises discretionary authority without the prior written consent of the customer.

        We and the Apollo Funds as selling stockholders have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act, or to contribute to payments the underwriters may be required to make because of any of those liabilities.

Notice to Prospective Investors in the European Economic Area

        In relation to each member state of the European Economic Area that has implemented the Prospectus Directive (each, a relevant member state), with effect from and including the date on which the Prospectus Directive is implemented in that relevant member state (the relevant implementation

148

date), an offer of shares described in this prospectus may not be made to the public in that relevant member state other than:

•

to any legal entity which is a qualified investor as defined in the Prospectus Directive;

•

to fewer than 100 or, if the relevant member state has implemented the relevant provision of the 2010 PD Amending Directive, 150 natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive, subject to obtaining the prior consent of the relevant Dealer or Dealers nominated by us for any such offer; or

•

in any other circumstances falling within Article 3(2) of the Prospectus Directive,

provided that no such offer of shares shall require us or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive.

        For purposes of this provision, the expression an "offer of securities to the public" in any relevant member state means the communication in any form and by any means of sufficient information on the terms of the offer and the shares to be offered so as to enable an investor to decide to purchase or subscribe for the shares, as the expression may be varied in that member state by any measure implementing the Prospectus Directive in that member state, and the expression "Prospectus Directive" means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive, to the extent implemented in the relevant member state) and includes any relevant implementing measure in the relevant member state. The expression 2010 PD Amending Directive means Directive 2010/73/EU.

        The sellers of the shares have not authorized and do not authorize the making of any offer of shares through any financial intermediary on their behalf, other than offers made by the underwriters with a view to the final placement of the shares as contemplated in this prospectus. Accordingly, no purchaser of the shares, other than the underwriters, is authorized to make any further offer of the shares on behalf of the sellers or the underwriters.

Notice to Prospective Investors in the United Kingdom

        This prospectus is only being distributed to, and is only directed at, persons in the United Kingdom that are qualified investors within the meaning of Article 2(1)(e) of the Prospectus Directive that are also (i) investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the "Order") or (ii) high net worth entities, and other persons to whom it may lawfully be communicated, falling within Article 49(2)(a) to (d) of the Order (each such person being referred to as a "relevant person"). This prospectus and its contents are confidential and should not be distributed, published or reproduced (in whole or in part) or disclosed by recipients to any other persons in the United Kingdom. Any person in the United Kingdom that is not a relevant person should not act or rely on this document or any of its contents.

Notice to Prospective Investors in France

        Neither this prospectus nor any other offering material relating to the shares described in this prospectus has been submitted to the clearance procedures of the Autorité des Marchés Financiers or of the competent authority of another member state of the European Economic Area and notified to the Autorité des Marchés Financiers. The shares have not been offered or sold and will not be offered or sold, directly or indirectly, to the public in France. Neither this prospectus nor any other offering material relating to the shares has been or will be:

•

released, issued, distributed or caused to be released, issued or distributed to the public in France; or

149

•

used in connection with any offer for subscription or sale of the shares to the public in France.

        Such offers, sales and distributions will be made in France only:

•

to qualified investors (investisseurs qualifiés) and/or to a restricted circle of investors (cercle restreint d'investisseurs), in each case investing for their own account, all as defined in, and in accordance with articles L.411-2, D.411-1, D.411-2, D.734-1, D.744-1, D.754-1 and D.764-1 of the French Code monétaire et financier;

•

to investment services providers authorized to engage in portfolio management on behalf of third parties; or

•

in a transaction that, in accordance with article L.411-2-II-1°-or-2°-or 3° of the French Code monétaire et financier and article 211-2 of the General Regulations (Règlement Général) of the Autorité des Marchés Financiers, does not constitute a public offer (appel public à l'épargne).

        The shares may be resold directly or indirectly, only in compliance with articles L.411-1, L.411-2, L.412-1 and L.621-8 through L.621-8-3 of the French Code monétaire et financier.

Notice to Prospective Investors in Hong Kong

        The shares may not be offered or sold in Hong Kong by means of any document other than (i) in circumstances which do not constitute an offer to the public within the meaning of the Companies Ordinance (Cap. 32, Laws of Hong Kong), or (ii) to "professional investors" within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder, or (iii) in other circumstances which do not result in the document being a "prospectus" within the meaning of the Companies Ordinance (Cap. 32, Laws of Hong Kong) and no advertisement, invitation or document relating to the shares may be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public in Hong Kong (except if permitted to do so under the laws of Hong Kong) other than with respect to shares which are or are intended to be disposed of only to persons outside Hong Kong or only to "professional investors" within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder.

Notice to Prospective Investors in Japan

        The shares offered in this prospectus have not been and will not be registered under the Financial Instruments and Exchange Law of Japan. The shares have not been offered or sold and will not be offered or sold, directly or indirectly, in Japan or to or for the account of any resident of Japan (including any corporation or other entity organized under the laws of Japan), except (i) pursuant to an exemption from the registration requirements of the Financial Instruments and Exchange Law and (ii) in compliance with any other applicable requirements of Japanese law.

Notice to Prospective Investors in Singapore

        This prospectus has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the shares may not be circulated or distributed, nor may the shares be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor under Section 274 of the Securities and Futures Act, Chapter 289 of Singapore (the "SFA"), (ii) to a relevant person pursuant to Section 275(1), or any person pursuant to Section 275(1A), and in accordance with the conditions specified in Section 275 of the SFA or (iii) otherwise pursuant to, and in accordance

150

with the conditions of, any other applicable provision of the SFA, in each case subject to compliance with conditions set forth in the SFA.

        Where the shares are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

•

a corporation (which is not an accredited investor (as defined in Section 4A of the SFA)) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or

•

a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary of the trust is an individual who is an accredited investor,

shares, debentures and units of shares and debentures of that corporation or the beneficiaries' rights and interest (howsoever described) in that trust shall not be transferred within six months after that corporation or that trust has acquired the shares pursuant to an offer made under Section 275 of the SFA except:

•

to an institutional investor (for corporations, under Section 274 of the SFA) or to a relevant person defined in Section 275(2) of the SFA, or to any person pursuant to an offer that is made on terms that such shares, debentures and units of shares and debentures of that corporation or such rights and interest in that trust are acquired at a consideration of not less than S$200,000 (or its equivalent in a foreign currency) for each transaction, whether such amount is to be paid for in cash or by exchange of securities or other assets, and further for corporations, in accordance with the conditions specified in Section 275 of the SFA;

•

where no consideration is or will be given for the transfer; or

•

where the transfer is by operation of law.

Notice to Prospective Investors in Australia

        No placement document, prospectus, product disclosure statement or other disclosure document has been lodged with the Australian Securities and Investments Commission, in relation to the offering. This prospectus does not constitute a prospectus, product disclosure statement or other disclosure document under the Corporations Act 2001 (the "Corporations Act"), and does not purport to include the information required for a prospectus, product disclosure statement or other disclosure document under the Corporations Act.

        Any offer in Australia of the shares may only be made to persons (the "Exempt Investors") who are "sophisticated investors" (within the meaning of section 708(8) of the Corporations Act), "professional investors" (within the meaning of section 708(11) of the Corporations Act) or otherwise pursuant to one or more exemptions contained in section 708 of the Corporations Act so that it is lawful to offer the shares without disclosure to investors under Chapter 6D of the Corporations Act.

        The shares applied for by Exempt Investors in Australia must not be offered for sale in Australia in the period of 12 months after the date of allotment under the offering, except in circumstances where disclosure to investors under Chapter 6D of the Corporations Act would not be required pursuant to an exemption under section 708 of the Corporations Act or otherwise or where the offer is pursuant to a disclosure document which complies with Chapter 6D of the Corporations Act. Any person acquiring shares must observe such Australian on-sale restrictions.

        This prospectus contains general information only and does not take account of the investment objectives, financial situation or particular needs of any particular person. It does not contain any securities recommendations or financial product advice. Before making an investment decision,

151

investors need to consider whether the information in this prospectus is appropriate to their needs, objectives and circumstances, and, if necessary, seek expert advice on those matters.

Notice to Prospective Investors in the Dubai International Financial Centre

        This prospectus relates to an Exempt Offer in accordance with the Offered Securities Rules of the Dubai Financial Services Authority ("DFSA"). This prospectus is intended for distribution only to persons of a type specified in the Offered Securities Rules of the DFSA. It must not be delivered to, or relied on by, any other person. The DFSA has no responsibility for reviewing or verifying any documents in connection with Exempt Offers. The DFSA has not approved this prospectus nor taken steps to verify the information set forth herein and has no responsibility for the prospectus. The shares to which this prospectus relates may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the shares offered should conduct their own due diligence on the shares. If you do not understand the contents of this prospectus you should consult an authorized financial advisor.

Notice to Prospective Investors in Switzerland

        We have not and will not register with the Swiss Financial Market Supervisory Authority ("FINMA") as a foreign collective investment scheme pursuant to Article 119 of the Federal Act on Collective Investment Scheme of 23 June 2006, as amended ("CISA"), and accordingly the securities being offered pursuant to this prospectus have not and will not be approved, and may not be licenseable, with FINMA. Therefore, the securities have not been authorized for distribution by FINMA as a foreign collective investment scheme pursuant to Article 119 CISA and the securities offered hereby may not be offered to the public (as this term is defined in Article 3 CISA) in or from Switzerland. The securities may solely be offered to "qualified investors," as this term is defined in Article 10 CISA, and in the circumstances set out in Article 3 of the Ordinance on Collective Investment Scheme of 22 November 2006, as amended ("CISO"), such that there is no public offer. Investors, however, do not benefit from protection under CISA or CISO or supervision by FINMA. This prospectus and any other materials relating to the securities are strictly personal and confidential to each offeree and do not constitute an offer to any other person. This prospectus may only be used by those qualified investors to whom it has been handed out in connection with the offer described herein and may neither directly or indirectly be distributed or made available to any person or entity other than its recipients. It may not be used in connection with any other offer and shall in particular not be copied and/or distributed to the public in Switzerland or from Switzerland. This prospectus does not constitute an issue prospectus as that term is understood pursuant to Article 652a and/or 1156 of the Swiss Federal Code of Obligations. We have not applied for a listing of the securities on the SIX Swiss Exchange or any other regulated securities market in Switzerland, and consequently, the information presented in this prospectus does not necessarily comply with the information standards set out in the listing rules of the SIX Swiss Exchange and corresponding prospectus schemes annexed to the listing rules of the SIX Swiss Exchange.

152

LEGAL MATTERS

        The validity of our common stock offered by this prospectus will be passed upon for us by Latham & Watkins LLP, Houston, Texas. Certain legal matters in connection with this offering will be passed upon for the underwriters by Baker Botts L.L.P., Houston, Texas.

EXPERTS

        The consolidated financial statements of Athlon Holdings LP at December 31, 2012 and 2011, and for each of the two years in the period ended December 31, 2012, appearing in this Prospectus and Registration Statement have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their report thereon appearing elsewhere herein, and are included in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

        The balance sheet of Athlon Energy Inc. as of April 25, 2013, appearing in this Prospectus and Registration Statement has been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their report thereon appearing elsewhere herein, and is included in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

        The carve out financial statements of the Element Petroleum, LP Permian Basin Operations as of and for the nine months ended September 30, 2011 included in the registration statement of which this prospectus is a part, have been audited by UHY LLP, an independent registered public accounting firm, as set forth in their report thereon appearing elsewhere herein, and are included in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

        The information included in this prospectus regarding estimated quantities of proved reserves, the future net revenues from those reserves and their present value as of December 31, 2012 and 2011 is based on proved reserve reports prepared by Cawley, Gillespie & Associates, Inc., our independent petroleum engineers. These estimates are included in this prospectus in reliance upon the authority of such firm as an expert in these matters.

WHERE YOU CAN FIND MORE INFORMATION

        We have filed with the SEC a registration statement on Form S-1 (including the exhibits, schedules and amendments thereto) under the Securities Act, with respect to the shares of our common stock offered hereby. This prospectus does not contain all of the information set forth in the registration statement and the exhibits and schedules thereto. For further information with respect to us and the common stock offered hereby, we refer you to the registration statement and the exhibits and schedules filed therewith. Statements contained in this prospectus as to the contents of any contract, agreement or any other document are summaries of the material terms of this contract, agreement or other document. With respect to each of these contracts, agreements or other documents filed as an exhibit to the registration statement, reference is made to the exhibits for a more complete description of the matter involved. A copy of the registration statement, and the exhibits and schedules thereto, may be inspected without charge at the Public Reference Room of the SEC at 100 F Street N.E., Washington, DC 20549. Copies of these materials may be obtained from such office, upon payment of a duplicating fee. Please call the SEC at 1-800-SEC-0330 for further information on the operation of the Public Reference Room. The SEC maintains a website at www.sec.gov that contains reports, proxy and information statements and other information regarding registrants that file electronically with the SEC.

153

GLOSSARY

        The terms defined in this section are used throughout this prospectus:

        "3-D seismic." Geophysical data that depict the subsurface strata in three dimensions. 3-D seismic typically provides a more detailed and accurate interpretation of the subsurface strata than 2-D, or two-dimensional, seismic.

        "Basin." A large natural depression on the earth's surface in which sediments generally brought by water accumulate.

        "Bbl." One stock tank barrel, of 42 U.S. gallons liquid volume, used in reference to crude oil, condensate or natural gas liquids.

        "Bbl/D." One Bbl per day.

        "Bcf." One billion cubic feet of natural gas.

        "BOE." One barrel of oil equivalent, with 6,000 cubic feet of natural gas being equivalent to one barrel of oil.

        "BOE/D." One barrel of oil equivalent per day.

        "British thermal unit (Btu)." The heat required to raise the temperature of a one-pound mass of water from 58.5 to 59.5 degrees Fahrenheit.

        "Cash operating expense." Equals lease operating expense plus production, severance and ad valorem tax, processing, gathering and overhead and general and administrative expense less non-cash equity-based compensation expense and acquisition costs.

        "Completion." The process of treating a drilled well followed by the installation of permanent equipment for the production of oil or natural gas, or in the case of a dry hole, the reporting of abandonment to the appropriate agency.

        "Condensate." A mixture of hydrocarbons that exists in the gaseous phase at original reservoir temperature and pressure, but that, when produced, is in the liquid phase at surface pressure and temperature.

        "Developed acreage." The number of acres that are allocated or assignable to productive wells or wells capable of production.

        "Development capital." Expenditures to obtain access to proved reserves and to construct facilities for producing, treating and storing hydrocarbons.

        "Development well." A well drilled within the proved area of an oil or natural gas reservoir to the depth of a stratigraphic horizon known to be productive.

        "Dry hole." A well found to be incapable of producing hydrocarbons in sufficient quantities such that proceeds from the sale of such production exceed production expenses and taxes.

        "Economically producible." A resource that generates revenue that exceeds, or is reasonably expected to exceed, the costs of the operation. For a complete definition of economically producible, refer to the SEC's Regulation S-X, Rule 4-10(a)(10).

        "Enhanced recovery." The recovery of hydrocarbons through the injection of liquids or gases into the reservoir, supplementing its natural energy. Enhanced recovery methods are often applied when production slows due to depletion of the natural pressure.

        "Estimated ultimate recovery (EUR)." The sum of gross reserves remaining as of a given date and cumulative production as of that date.

G-1

        "Exploratory well." A well drilled to find a new field or to find a new reservoir in a field previously found to be productive of oil or natural gas in another reservoir.

        "Finding and Development (F&D) costs." F&D costs are calculated by dividing the sum of property acquisition costs, exploration costs and development costs for the year, by the sum of proved reserve extensions, discoveries, acquisitions and revisions for the year.

        "Field." An area consisting of a single reservoir or multiple reservoirs all grouped on or related to the same individual geological structural feature and/or stratigraphic condition. The field name refers to the surface area, although it may refer to both the surface and the underground productive formations. For a complete definition of field, refer to the SEC's Regulation S-X, Rule 4-10(a)(15).

        "Formation." A layer of rock which has distinct characteristics that differ from nearby rock.

        "GAAP." Accounting principles generally accepted in the United States.

        "Gross acres" or "Gross wells." The total acres or wells, as the case may be, in which an entity owns a working interest.

        "Held by production acreage." Acreage covered by a mineral lease that perpetuates a company's right to operate a property as long as the property produces a minimum paying quantity of oil or gas.

        "Horizontal drilling." A drilling technique used in certain formations where a well is drilled vertically to a certain depth and then drilled at a right angle within a specified interval.

        "Infill wells." Wells drilled into the same pool as known producing wells so that oil or natural gas does not have to travel as far through the formation.

        "IRS." Internal Revenue Service.

        "Lease operating expense (LOE)." All direct and allocated indirect costs of lifting hydrocarbons from a producing formation to the surface constituting part of the current operating expenses of a working interest. Such costs include labor, superintendence, supplies, repairs, maintenance, allocated overhead charges, workover, insurance and other expenses incidental to production, but exclude lease acquisition or drilling or completion expenses.

        "LIBOR." London Interbank Offered Rate.

        "MBbl." One thousand barrels of crude oil, condensate or NGLs.

        "MBOE." One thousand barrels of oil equivalent.

        "Mcf." One thousand cubic feet of natural gas.

        "MMBOE." One million barrels of oil equivalent.

        "MMBtu." One million British thermal units.

        "MMcf." One million cubic feet of natural gas.

        "Natural gas liquids (NGLs)." The combination of ethane, propane, butane, isobutane and natural gasolines that when removed from natural gas become liquid under various levels of higher pressure and lower temperature.

        "Net acres" or "Net wells." The percentage of total acres or wells, as the case may be, an owner has out of a particular number of gross acres or wells. For example, an owner who has 50% interest in 100 gross acres owns 50 net acres.

        "Net revenue interest." An owner's interest in the revenues of a well after deducting proceeds allocated to royalty and overriding interests.

G-2

        "NYMEX." The New York Mercantile Exchange.

        "Operator." The entity responsible for the exploration, development and production of a well or lease.

        "Present value of future net revenues (PV-10)." The estimated future gross revenue to be generated from the production of proved reserves, net of estimated production and future development and abandonment costs, using prices and costs in effect at the determination date, before income taxes, and without giving effect to non-property-related expenses, discounted to a present value using an annual discount rate of 10% in accordance with the guidelines of the SEC.

        "Productive well." A well that is found to be capable of producing hydrocarbons in sufficient quantities such that proceeds from the sale of the production exceed production expenses and taxes.

        "Proved developed reserves." Proved reserves that can be expected to be recovered:

            i.  Through existing wells with existing equipment and operating methods or in which the cost of the required equipment is relatively minor compared with the cost of a new well; or

           ii.  Through installed extraction equipment and infrastructure operational at the time of the reserves estimate if the extraction is by means not involving a well.

        "Proved reserves." Those quantities of oil and natural gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible—from a given date forward, from known reservoirs, and under existing economic conditions, operating methods, and government regulations—prior to the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic or probabilistic methods are used for the estimation. The project to extract the hydrocarbons must have commenced, or the operator must be reasonably certain that it will commence, the project within a reasonable time. For a complete definition of proved oil and natural gas reserves, refer to the SEC's Regulation S-X, Rule 4-10(a)(22).

        "Proved undeveloped reserves (PUDs)." Proved reserves that are expected to be recovered from new wells on undrilled acreage, or from existing wells where a relatively major expenditure is required for recompletion.

        Reserves on undrilled acreage shall be limited to those directly offsetting development spacing areas that are reasonably certain of production when drilled, unless evidence using reliable technology exists that establishes reasonable certainty of economic producibility at greater distances.

        Undrilled locations can be classified as having undeveloped reserves only if a development plan has been adopted indicating that they are scheduled to be drilled within five years, unless the specific circumstances justify a longer time.

        Under no circumstances shall estimates for proved undeveloped reserves be attributable to any acreage for which an application of fluid injection or other improved recovery technique is contemplated, unless such techniques have been proved effective by actual projects in the same reservoir or an analogous reservoir, or by other evidence using reliable technology establishing reasonable certainty.

        "Reasonable certainty." A high degree of confidence. For a complete definition of reasonable certainty, refer to the SEC's Regulation S-X, Rule 4-10(a)(24).

        "Recompletion." The process of re-entering an existing wellbore that is either producing or not producing and completing new reservoirs in an attempt to establish or increase existing production.

G-3

        "Reliable technology." A grouping of one or more technologies (including computational methods) that have been field tested and have been demonstrated to provide reasonably certain results with consistency and repeatability in the formation being evaluated or in an analogous formation.

        "Reserve/production ratio (R/P Ratio)." The number of years proved reserves would last assuming current production continued at the January 2013 rate. This ratio is calculated by dividing annualized average daily production into the proved reserve quantity. Because production rates naturally decline over time, the R/P Ratio is not a useful estimate of how long properties should economically produce.

        "Reserves." Estimated remaining quantities of oil and natural gas and related substances anticipated to be economically producible, as of a given date, by application of development prospects to known accumulations. In addition, there must exist, or there must be a reasonable expectation that there will exist, the legal right to produce or a revenue interest in the production, installed means of delivering oil and natural gas or related substances to market and all permits and financing required to implement the project.

        "Reservoir." A porous and permeable underground formation containing a natural accumulation of producible hydrocarbons that is confined by impermeable rock or water barriers and is separate from other reservoirs.

        "Royalty." An interest in an oil and natural gas lease that gives the owner the right to receive a portion of the production from the leased acreage (or of the proceeds from the sale thereof), but does not require the owner to pay any portion of the production or development costs on the leased acreage. Royalties may be either landowner's royalties, which are reserved by the owner of the leased acreage at the time the lease is granted, or overriding royalties, which are usually reserved by an owner of the leasehold in connection with a transfer to a subsequent owner.

        "SEC." The United States Securities and Exchange Commission.

        "Spacing." The distance between wells producing from the same reservoir. Spacing is often expressed in terms of acres, e.g., 40-acre spacing, and is often established by regulatory agencies.

        "Stacked pay." Multiple geological zones that potentially contain hydrocarbons and are arranged in a vertical stack.

        "Standardized Measure." The present value of estimated future net revenue to be generated from the production of proved reserves, determined in accordance with the rules and regulations of the SEC (using 12-month first-day-of-the-month oil and natural gas average prices, as adjusted for basis or location differentials, held constant over the life of the reserves and costs in effect as of the date of estimation), less future development and production costs and income taxes, and discounted at 10% per annum to reflect the timing of future net revenue. Standardized Measure does not give effect to derivative transactions.

        "TD." Total depth.

        "Undeveloped acreage." Lease acreage on which wells have not been drilled or completed to a point that would permit the production of economic quantities of oil or natural gas regardless of whether such acreage contains proved reserves.

        "Wellbore." The hole drilled by the bit that is equipped for oil or gas production on a completed well. Also called well or borehole.

        "Working interest." The right granted to the lessee of a property to explore for and to produce and own oil, natural gas or other minerals. The working interest owners bear the exploration, development and operating costs on either a cash, penalty or carried basis.

        "Workover." Operations on a producing well to restore or increase production.

        "WTI." West Texas Intermediate crude oil, which is a light, sweet crude oil, characterized by an American Petroleum Institute gravity, or API gravity, between 39 and 41 and a sulfur content of approximately 0.4 weight percent that is used as a benchmark for other crude oils.

G-4

INDEX TO FINANCIAL STATEMENTS

	Page
ATHLON ENERGY INC.
BALANCE SHEET
Report of Independent Registered Public Accounting Firm	F-2
Balance Sheet as of April 25, 2013	F-3
Notes to Balance Sheet	F-4
UNAUDITED PRO FORMA FINANCIAL STATEMENTS
Introduction	F-5
Unaudited Pro Forma Balance Sheet as of March 31, 2013	F-6
Unaudited Pro Forma Statement of Operations for the Three Months Ended March 31, 2013	F-7
Unaudited Pro Forma Statement of Operations for the Year Ended December 31, 2012	F-8
Notes to Unaudited Pro Forma Financial Statements	F-9
ATHLON HOLDINGS LP
UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS
Consolidated Balance Sheets as of March 31, 2013 and December 31, 2012	F-15
Consolidated Statements of Operations for the Three Months Ended March 31, 2013 and 2012	F-16
Consolidated Statement of Changes in Partners' Equity for the Three Months Ended March 31, 2013	F-17
Consolidated Statements of Cash Flows for the Three Months Ended March 31, 2013 and 2012	F-18
Notes to Consolidated Financial Statements	F-19
AUDITED CONSOLIDATED FINANCIAL STATEMENTS
Report of Independent Registered Public Accounting Firm	F-32
Consolidated Balance Sheets as of December 31, 2012 and 2011	F-33
Consolidated Statements of Operations for the Years Ended December 31, 2012 and 2011	F-34
Consolidated Statements of Changes in Partners' Equity for the Years Ended December 31, 2012 and 2011	F-35
Consolidated Statements of Cash Flows for the Years Ended December 31, 2012 and 2011	F-36
Notes to Consolidated Financial Statements	F-37
Supplementary Information	F-58
ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS
AUDITED CARVE OUT FINANCIAL STATEMENTS
Report of Independent Registered Public Accounting Firm	F-63
Carve Out Balance Sheet as of September 30, 2011	F-64
Carve Out Statement of Operations for the Nine Months Ended September 30, 2011	F-65
Carve Out Statement of Changes in Owner's Net Equity for the Nine Months Ended September 30, 2011	F-66
Carve Out Statement of Cash Flows for the Nine Months Ended September 30, 2011	F-67
Notes to Carve Out Financial Statements	F-68

F-1

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Stockholders
Athlon Energy Inc.

        We have audited the accompanying balance sheet of Athlon Energy Inc. as of April 25, 2013. This balance sheet is the responsibility of the Company's management. Our responsibility is to express an opinion on this balance sheet based on our audit.

        We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the balance sheet is free of material misstatement. We were not engaged to perform an audit of the Company's internal control over financial reporting. Our audit included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the balance sheet, assessing the accounting principles used and significant estimates made by management, and evaluating the overall balance sheet presentation. We believe that our audit provides a reasonable basis for our opinion.

        In our opinion, the balance sheet referred to above presents fairly, in all material respects, the financial position of Athlon Energy Inc. at April 25, 2013, in conformity with U.S. generally accepted accounting principles.

/s/ Ernst & Young LLP

Fort Worth, Texas
June 4, 2013

F-2

ATHLON ENERGY INC.

BALANCE SHEET

	April 25, 2013
ASSETS
Current assets:
Receivable from stockholder	$	10
Total assets	$	10
STOCKHOLDER'S EQUITY
Stockholder's equity:
Common stock, $0.01 par value, 1,000 shares authorized, issued and outstanding	$	10
Total stockholder's equity	$	10

The accompanying notes are an integral part of this consolidated balance sheet.

F-3

ATHLON ENERGY INC.

NOTES TO BALANCE SHEET

Note 1. Formation of the Company and Description of Business

        Athlon Energy Inc. (together with its subsidiaries, the "Company"), a Delaware corporation, was formed on April 1, 2013 and is currently a wholly-owned subsidiary of Athlon Holdings GP LLC (the "General Partner"), a Delaware limited liability company. Athlon Holdings LP (together with its subsidiaries, "Holdings"), a Delaware limited partnership, was formed on July 22, 2011 and is an independent exploration and production company focused on the acquisition, development and exploitation of unconventional oil and liquids-rich natural gas reserves in the Permian Basin. The General Partner serves as the general partner of Holdings.

        On April 25, 2013, the Company was authorized to issue 1,000 shares of common stock, $.01 par value, and had 1,000 shares outstanding, all of which were owned by the General Partner. On April 25, 2013, the Company had a $10 receivable from the General Partner equal to the sales price of the shares of common stock the General Partner owns.

        There were no other transactions involving the Company as of April 25, 2013.

Note 2. Subsequent Events

        The Company intends to offer shares of common stock to the public in an offering registered under the Securities Act of 1933, as amended.

        Subsequent to April 25, 2013, the Company collected the $10 receivable from the General Partner.

        On April 26, 2013, Holdings underwent a corporate reorganization and as a result, the Company became the holding company of Holdings. The Company will operate and control all of the business and affairs and consolidate the financial results of Holdings. In the reorganization, Apollo Investment Fund VII, L.P. and its parallel funds (the "Apollo Funds") entered into a number of distribution and contribution transactions pursuant to which the Apollo Funds exchanged their Class A limited partner interests in Holdings for common stock of the Company. The remaining holders of Class A limited partner interests in Holdings have not exchanged their interests in the reorganization transactions. In addition, the holders of the Class B limited partner interests in Holdings exchanged their interests for common stock of the Company subject to the same vesting terms.

        Subsequent events have been considered through June 4, 2013, the date the balance sheet was issued.

F-4

ATHLON ENERGY INC.

UNAUDITED PRO FORMA FINANCIAL STATEMENTS

INTRODUCTION

        Athlon Energy Inc. (the "Company") incorporated in Delaware on April 1, 2013 and is an independent exploration and production company focused on the acquisition, development, and exploitation of unconventional oil and liquids-rich natural gas reserves in the Permian Basin. The Company plans to pursue an initial public offering of shares of common stock (the "Offering"). The accompanying unaudited pro forma financial statements give effect to the following transactions:

•

the issuance of $500 million of 7³/8% Senior Notes due 2021 on April 17, 2013 (the "Notes") and the application of the net proceeds received thereby to (1) repay a portion of indebtedness outstanding under the Company's credit agreement, (2) repay in full and terminate the Company's former second lien term loan, and (3) make a distribution to Athlon Holdings LP's Class A limited partners;

•

the reorganization of the Company as described in "Corporate Reorganization"; and

•

the completion of the Offering and the use of proceeds from the Offering as described in "Use of Proceeds".

The unaudited pro forma balance sheet assumes that the transactions occurred on March 31, 2013. The unaudited pro forma statements of operations assumes that the transactions occurred on January 1, 2012.

        The Company's accounting predecessor, Athlon Holdings LP ("Holdings"), conducted its operations as a limited partnership with all earnings taxed at the partner level. Following its corporate reorganization, the Company will be subject to subchapter C of the Internal Revenue Code and, as a result, will become taxable as a corporation and subject to U.S. federal and state income taxes at the entity level.

        The accompanying unaudited pro forma financial statements of the Company should be read together with the audited consolidated financial statements of Holdings as of and for the years ended December 31, 2012 and 2011 and the unaudited consolidated financial statements of Holdings as of March 31, 2013 and for the three months ended March 31, 2013 and 2012, both of which are included elsewhere in this prospectus. The accompanying unaudited pro forma financial statements of the Company were derived by making certain adjustments to the consolidated financial statements of Holdings. The adjustments are based on currently available information and certain estimates and assumptions. Therefore, the actual adjustments may differ from the pro forma adjustments. However, management believes that the assumptions provide a reasonable basis for presenting the significant effects of the transactions as contemplated and that the pro forma adjustments give appropriate effect to those assumptions and are properly applied in the unaudited pro forma financial statements.

        The unaudited pro forma financial statements and related notes are presented for illustrative purposes only. If the Offering and other transactions contemplated herein had occurred in the past, the Company's operating results might have been materially different from those presented in the unaudited pro forma financial statements. The unaudited pro forma financial statements should not be relied upon as an indication of operating results that the Company would have achieved if the Offering and other transactions contemplated herein had taken place on the specified date. In addition, future results may vary significantly from the results reflected in the unaudited pro forma financial statements of operations and should not be relied on as an indication of the future results the Company will have after the completion of the Offering and the other transactions contemplated by these unaudited pro forma financial statements.

F-5

ATHLON ENERGY INC.

UNAUDITED PRO FORMA BALANCE SHEET

March 31, 2013

(in thousands)

	Athlon Holdings LP Historical			Notes Offering Pro Forma Adjustments			Corporate Reorganization Pro Forma Adjustments			Initial Public Offering Pro Forma Adjustments			Pro Forma as Adjusted
ASSETS
Current assets:
Cash and cash equivalents	$	3,379		$	487,458	(a)	$	—		$	278,895	(g)	$	275,103
					(488,253	)(b)					(3,173	)(h)
					(703	)(c)					(2,500	)(j)
Accounts receivable		33,149			—			—			—			33,149
Inventory		1,023			—			—			—			1,023
Other		781			—			—			—			781
Total current assets		38,332			(1,498	)		—			273,222			310,056
Properties and equipment, at cost—full cost method:
Proved properties, including wells and related equipment		864,350			—			—			377	(k)		864,727
Unproved properties		95,892			—			—			—			95,892
Accumulated depletion, depreciation, and amortization		(91,829	)		—			—			—			(91,829	)
		868,413			—			—			377			868,790
Derivatives		2,204			—			—			—			2,204
Debt issuance costs		5,906			12,542	(a)		—			—			15,591
					(2,857	)(d)
Other		1,680			—			—			(395	)(i)		1,285
Total assets	$	916,535		$	8,187		$	—		$	273,204		$	1,197,926
LIABILITIES AND EQUITY
Current liabilities:
Accounts payable:
Trade	$	250		$	—		$	—		$	—		$	250
Affiliate		538			—			—			—			538
Accrued liabilities:
Lease operating		4,460			—			—			—			4,460
Production, severance, and ad valorem taxes		2,459			—			—			—			2,459
Development capital		29,986			—			—			—			29,986
Derivatives		4,599			—			—			—			4,599
Revenue payable		12,842			—			—			—			12,842
Other		3,232			(703	)(c)		—			—			2,529
Total current liabilities		58,366			(703	)		—			—			57,663
Derivatives		324			—			—			—			324
Asset retirement obligations, net of current portion		5,600			—			—			—			5,600
Long-term debt		416,426			500,000	(a)		—			(3,173	)(h)		500,000
					(413,253	)(b)
Deferred tax liability		2,361			—			19,002	(f)		—			21,363
Other		128			—			—			—			128
Total liabilities		483,205			86,044			19,002			(3,173	)		585,078
Commitments and contingencies
Equity:
Preferred stock		—			—			—			—			—
Common stock		—			—			10	(e)		*	(g)		10
											*	(1)
Additional paid-in capital		—			—			346,034	(e)		278,895	(g)		626,182
											(395	)(i)
											1,648	(k)
											*	(1)
Partners' capital		433,330			(75,000	)(b)		(355,473	)(e)		—			—
					(2,857	)(d)
Accumulated deficit		—			—			(19,002	)(f)		(2,500	)(j)		(22,773	)
											(1,271	)(k)
Total stockholders' equity		433,330			(77,857	)		(28,431	)		276,377			603,419
Noncontrolling interest		—			—			9,429	(e)		—			9,429
Total equity		433,330			(77,857	)		(19,002	)		276,377			612,848
Total liabilities and equity	$	916,535		$	8,187		$	—		$	273,204		$	1,197,926

*

To be completed by amendment.

The accompanying notes are an integral part of these unaudited pro forma financial statements.

F-6

ATHLON ENERGY INC.

UNAUDITED PRO FORMA STATEMENT OF OPERATIONS

For the Three Months Ended March 31, 2013

(in thousands)

	Athlon Holdings LP Historical		Notes Offering Pro Forma Adjustments			Corporate Reorganization Pro Forma Adjustments			Initial Public Offering Pro Forma Adjustments			Pro Forma as Adjusted
Revenues:
Oil	$	45,659	$	—		$	—		$	—		$	45,659
Natural gas		3,367		—			—			—			3,367
Natural gas liquids		5,720		—			—			—			5,720
Total revenues		54,746		—			—			—			54,746
Expenses:
Production:
Lease operating		7,237		—			—			—			7,237
Production, severance, and ad valorem taxes		3,694		—			—			—			3,694
Depletion, depreciation, and amortization		18,053		—			—			—			18,053
General and administrative		3,339		—			—			—			3,339
Derivative fair value loss		6,849		—			—			—			6,849
Other operating		194		—			—			—			194
Total expenses		39,366		—			—			—			39,366
Operating income (loss)		15,380		—			—			—			15,380
Interest expense		4,474		9,614	(a)		—			—			9,976
				(4,112)	(b)
Income (loss) before income taxes		10,906		(5,502	)		—			—			5,404
Income tax provision		27		—			1,994	(c)		—			2,021
Consolidated net income (loss)		10,879		(5,502	)		(1,994	)		—			3,383
Less: net income (loss) attributable to noncontrolling interest		—		—			168	(d)		*	(e)		168
Net income (loss) attributable to stockholders	$	10,879	$	(5,502	)	$	(2,162	)	$	—		$	3,215
Net income (loss) per common share (f):
Basic												$	*
Diluted												$	*
Weighted average common shares outstanding (f):
Basic													*
Diluted													*

*

To be completed by amendment.

The accompanying notes are an integral part of these unaudited pro forma financial statements.

F-7

ATHLON ENERGY INC.

UNAUDITED PRO FORMA STATEMENT OF OPERATIONS

For the Year Ended December 31, 2012

(in thousands)

	Athlon Holdings LP Historical			Notes Offering Pro Forma Adjustments			Corporate Reorganization Pro Forma Adjustments			Initial Public Offering Pro Forma Adjustments			Pro Forma as Adjusted
Revenues:
Oil	$	128,081		$	—		$	—		$	—		$	128,081
Natural gas		8,415			—			—			—			8,415
Natural gas liquids		20,615			—			—			—			20,615
Total revenues		157,111			—			—			—			157,111
Expenses:
Production:
Lease operating		25,503			—			—			—			25,503
Production, severance, and ad valorem taxes		10,438			—			—			—			10,438
Depletion, depreciation, and amortization		54,456			—			—			—			54,456
General and administrative		9,678			—			—			—			9,678
Acquisitions costs		876			—			—			—			876
Derivative fair value gain		(9,293	)		—			—			—			(9,293	)
Other operating		562			—			—			—			562
Total expenses		92,220			—			—			—			92,220
Operating income (loss)		64,891			—			—			—			64,891
Interest expense		9,949			39,096	(a)		—			—			40,590
					(8,455	)(b)
Income (loss) before income taxes		54,942			(30,641	)		—			—			24,301
Income tax provision		1,928			—			7,158	(c)		—			9,086
Consolidated net income (loss)		53,014			(30,641	)		(7,158	)		—			15,215
Less: net income (loss) attributable to
noncontrolling interest		—			—			753	(d)		*	(e)		753
Net income (loss) attributable to stockholders	$	53,014		$	(30,641	)	$	(7,911	)	$	—		$	14,462
Net income (loss) per common share (f):
Basic													$	*
Diluted													$	*
Weighted average common shares outstanding (f):
Basic														*
Diluted														*

*

To be completed by amendment.

The accompanying notes are an integral part of these unaudited pro forma financial statements.

F-8

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS

Note 1. Basis of Presentation, the Offering, and Other Transactions

        The historical financial information is derived from the consolidated financial statements of Holdings included elsewhere in this prospectus. For purposes of the unaudited pro forma balance sheet, it is assumed that the transactions had taken place on March 31, 2013. For purposes of the unaudited pro forma statements of operations, it is assumed all transactions had taken place on January 1, 2012.

        Upon closing of the Offering, the Company expects to incur direct, incremental general and administrative expenses as a result of being a publicly traded company, including, but not limited to, costs associated with annual and quarterly reports to stockholders, tax return preparation, independent auditor fees, investor relations activities, registrar and transfer agent fees, incremental director and officer liability insurance costs, and independent director compensation. The Company estimates these direct, incremental general and administrative expenses initially to total approximately $2.0 million per year. These direct, incremental general and administrative expenditures are not reflected in the historical consolidated financial statements or in the unaudited pro forma financial statements.

        Upon closing of the Offering, the limited partnership agreement of Holdings will be amended and restated to, among other things, modify Holdings' capital structure by replacing its different classes of interests with a single new class of units that we refer to as the "New Holdings Units." The members of the Company's management team and certain employees that hold Class A limited partner interests will own New Holdings Units and will enter into an exchange agreement under which (subject to the terms of the exchange agreement) they will have the right, under certain circumstances, to exchange their New Holdings Units for shares of the Company's common stock on a one-for-one basis, subject to customary conversion rate adjustments for stock splits, stock dividends, and reclassifications. All other New Holdings Units will be held by the Company. As a holder exchanges its New Holdings Units, the Company's interest in Holdings will be correspondingly increased.

        The Company will enter into a tax receivable agreement for the benefit of the holders of New Holdings Units. Future exchanges of New Holdings Units for the Company's common stock under the exchange agreement are expected to result in increases in the tax basis of Holdings' assets that otherwise would not have been available. Depletion from the increase in tax basis will be available, subject to limitations, to reduce the amount of tax that the Company would be required to pay in the future.

        Under the tax receivable agreement, the Company will agree to pay to the holders of New Holdings Units (or certain permitted transferees thereof) 85% of the actual reduction in U.S. federal, state, and local tax payments that the Company is deemed to realize as a result of increases in tax basis and certain other tax benefits related to exchanges of New Holdings Units pursuant to the exchange agreement, including tax benefits attributable to payments under the tax receivable agreement. The beneficiaries under the tax receivable agreement will not reimburse the Company for any payments previously made under the tax receivable agreement if such benefits are subsequently disallowed, although future payments would be adjusted to the extent possible to reflect the result of such disallowance. As a result, in certain circumstances, payments could be made under the tax receivable agreement in excess of the Company's reported deferred tax assets. The obligation to pay 85% of the amount of such cash savings to the holders of New Holdings Units is the Company's obligation, and not the obligation of Holdings or any other subsidiary. Please read "Corporate Reorganization" and "Certain Relationships and Related Party Transactions—Tax Receivable Agreement."

        The step-up in basis will depend on the fair value of the New Holdings Units at conversion. There is no intent of the holders of New Holdings Units to exchange their units for shares of the Company's common stock in the foreseeable future. In addition, the Company does not expect to be in a tax

F-9

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS (Continued)

Note 1. Basis of Presentation, the Offering, and Other Transactions (Continued)

paying position before 2019. Therefore, the Company cannot presently estimate what the benefit or payments under the tax receivable agreement will be on a factually supportable basis. If the tax receivable agreement were terminated immediately after the Offering, the Company estimates it would be required to make an early termination payment of approximately $5.3 million to the holders of the New Holdings Units.

Note 2. Pro Forma Adjustments and Assumptions

        The Company made the following adjustments and assumptions in the preparation of the unaudited pro forma balance sheet:

(a)

Reflects gross proceeds of $500 million from the issuance of the Notes, net of underwriting discounts and commissions of $10 million, in the aggregate, and additional debt issuance costs of approximately $2.5 million.



(b)

Reflects the use of net proceeds from the issuance of the Notes and cash on hand to (1) repay approximately $288.3 million of outstanding borrowings under the Company's credit agreement, (2) repay in full and terminate the Company's former second lien term loan of $125 million, and (3) make a $75 million distribution to Holdings' Class A limited partners.



(c)

Reflects the use of net proceeds from the issuance of the Notes to pay approximately $0.7 million of accrued interest on the Company's former second lien term loan.



(d)

Reflects the write off of approximately $2.9 million of debt issuance costs related to (1) the reduction in the borrowing base under the Company's credit agreement from $360 million to $267.5 million in connection with the issuance of the Notes and (2) the repayment in full and termination of the Company's former second lien term loan. The write off of debt issuance costs related to the Company's credit agreement was a result of a decrease in borrowing capacity as determined in accordance with ASC 470-50, "Debt—Modifications and Extinguishments—Derecognition".



(e)

Reflects (1) the issuance of 860,907 shares of common stock to Apollo in exchange for their Class A limited partner interest in Holdings, (2) the issuance of 100,000 shares of common stock to the Company's management and certain employees in exchange for their Class B limited partner interests in Holdings, (3) the reclassification of management's Class A limited partner interests in Holdings to noncontrolling interest of the Company, and (4) the reclassification of the Company's predecessor's retained earnings to additional paid-in capital. The 100,000 shares of common stock issued to the Company's management and certain employees in exchange for their Class B limited partner interests in Holdings are subject to the same vesting and performance terms as the original grant.



(f)

Reflects estimated change in long-term deferred tax liabilities for temporary differences between the historical cost basis and tax basis of the Company's assets and liabilities as the result of its change in tax status to a subchapter C corporation. A corresponding charge to earnings has not been reflected in the unaudited pro forma statement of operations as the charge is considered non-recurring.



(g)

Reflects estimated gross proceeds of $300 million from the issuance and sale of              shares of common stock at an assumed initial public offering price of $          per share, net of estimated underwriting discounts and commissions of $15 million, in the aggregate, and additional estimated expenses related to the Offering of approximately $4.6 million.

F-10

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS (Continued)

Note 2. Pro Forma Adjustments and Assumptions (Continued)

(h)

Reflects the use of a portion of the net proceeds from the Offering to repay approximately $3.2 million of remaining outstanding borrowings under the Company's credit agreement.



(i)

Reflects the reclassification of expenses related to the Offering incurred prior to March 31, 2013 of approximately $0.4 million.



(j)

Reflects the termination of the Company's Services Agreement, dated August 23, 2010, and, in connection with the termination, the payment to Apollo of approximately $2.5 million. Such payment corresponds to the present value as of the date of termination of the aggregate annual fees that would have been payable during the remainder of the term of the Services Agreement (assuming a term ending on August 23, 2020) using a discount rate of 8.0%. This adjustment is not reflected in the accompanying unaudited pro forma statements of operations as it is considered non-recurring.



(k)

Reflects the recognition of the remaining unrecognized equity-based compensation related to the 100,000 shares of common stock which were issued to the Company's management in exchange for their Class B limited partner interests in Holdings. The terms of the underlying agreements cause the awards to immediately vest upon the closing of the Offering. Includes the estimated grant date fair value of 2,725 Class B limited partner interests granted during April 2013. This adjustment is not reflected in the accompanying unaudited pro forma statements of operations as it is considered non-recurring.



(l)

Reflects the stock split for shares held by the Company's existing stockholders prior to the consummation of this Offering.

        The Company made the following adjustments and assumptions in the preparation of the unaudited pro forma statements of operations:

(a)

Reflects estimated incremental interest expense and amortization of debt issuance costs associated with the issuance of the Notes.



(b)

Reflects (1) the elimination of interest expense and amortization of debt issuance costs related to the Company's former second lien term loan, which was repaid in full and terminated in connection with the issuance of the Notes, and (2) the reduction in interest expense under the Company's credit agreement, partially offset by an increase in unused commitment fees. On a pro forma basis, there would have been no outstanding borrowings under the Company's credit agreement as of January 1, 2012.

A ¹/8% change in LIBOR would have had no effect on our interest expense as we would have had no outstanding variable rate debt during the periods presented on a pro forma basis.

(c)

Reflects estimated incremental income tax provision associated with the Company's historical results of operations and the Notes Offering pro forma adjustments assuming the Company's earnings had been subject to federal income tax as a subchapter C corporation using an effective tax rate of approximately 37.4%. This rate is inclusive of federal, state, and local income taxes.



(d)

Reflects the reduction in consolidated net income (loss) attributable to noncontrolling interest for the Company's historical results of operations and the Notes Offering pro forma adjustments. As described in "Corporate Reorganization", the Company has become the sole managing partner of Holdings and will initially own less than 100% of the economic interest in Holdings, but will have 100% of the voting power and control the management of Holdings.

F-11

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS (Continued)

Note 2. Pro Forma Adjustments and Assumptions (Continued)

Upon completion of the Company's reorganization, the noncontrolling interest was approximately 3.2%.

(e)

Reflects the reduction in consolidated net income (loss) attributable to noncontrolling interest for the change in noncontrolling interest percentage as a result of the Offering. Upon consummation of the Offering, additional shares of common stock will be issued to Apollo, the Company's management and certain employees, and the investors in the Offering resulting in an increase in the Company's ownership percentage of Holdings. This will reduce the noncontrolling interest from approximately 3.2% to approximately          %.



(f)

Reflects basic and diluted income per common share for the issuance of shares of common stock in the Offering. Please read "Note 3. Pro Forma Earnings Per Share" for additional discussion.

Note 3. Pro Forma Earnings Per Share

        The following table reflects the pro forma allocation of net income to the Company's common stockholders and earnings per share ("EPS") computations for the periods indicated:

	Three months ended March 31, 2013		Year ended December 31, 2012
	(in thousands, except per share amounts)
Basic EPS
Numerator:
Basic net income attributable to stockholders	$	3,215	$	14,462
Denominator:
Basic weighted average shares outstanding		*		*
Basic EPS attributable to stockholders	$	*	$	*
Diluted EPS
Numerator:
Net income attributable to stockholders	$	3,215	$	14,462
Effect of conversion of New Holdings Units to shares of the Company's common stock		*		*
Diluted net income attributable to stockholders	$	*	$	*
Denominator:
Basic weighted average shares outstanding		*		*
Effect of conversion of New Holdings Units to shares of the Company's common stock		*		*
Diluted weighted average shares outstanding		*		*
Diluted EPS attributable to stockholders	$	*	$	*

*

To be completed by amendment.

F-12

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS (Continued)

Note 4. Supplementary Information

        The following pro forma standardized measure of the discounted net future cash flows and changes applicable to the Company's proved reserves reflect the effect of income taxes assuming the Company's standardized measure had been subject to federal income tax as a subchapter C corporation. The future cash flows are discounted at 10% per year and assume continuation of existing economic conditions.

        The standardized measure of discounted future net cash flows, in management's opinion, should be examined with caution. The basis for this table is the reserve studies prepared by independent petroleum engineering consultants, which contain imprecise estimates of quantities and rates of production of reserves. Revisions of previous year estimates can have a significant impact on these results. Also, exploration costs in one year may lead to significant discoveries in later years and may significantly change previous estimates of proved reserves and their valuation. Therefore, the standardized measure of discounted future net cash flow is not necessarily indicative of the fair value of the Company's proved oil and natural gas properties.

        The data presented should not be viewed as representing the expected cash flow from or current value of, existing proved reserves since the computations are based on a large number of estimates and arbitrary assumptions. Reserve quantities cannot be measured with precision and their estimation requires many judgmental determinations and frequent revisions. Actual future prices and costs are likely to be substantially different from the prices and costs utilized in the computation of reported amounts.

        The Company's pro forma standardized measure of discounted estimated future net cash flows was as follows as of December 31, 2012:

	Athlon Holdings LP Historical			Reorganization Pro Forma Adjustments			Pro Forma as Adjusted
	(in thousands)
Future cash inflows	$	5,361,058		$	—		$	5,361,058
Future production costs		(1,811,514	)		—			(1,811,514	)
Future development costs		(1,060,785	)		—			(1,060,785	)
Future income taxes		(37,527	)		(677,762	)		(715,289	)
Future net cash flows		2,451,232			(677,762	)		1,773,470
10% annual discount		(1,600,318	)		429,334			(1,170,984	)
Standardized measure of discounted estimated future net cash flows	$	850,914		$	(248,428	)	$	602,486

F-13

ATHLON ENERGY INC.

NOTES TO UNAUDITED PRO FORMA FINANCIAL STATEMENTS (Continued)

Note 4. Supplementary Information (Continued)

        The changes in Holdings' pro forma standardized measure of discounted estimated future net cash flows were as follows for 2012:

	Athlon Holdings LP Historical			Reorganization Pro Forma Adjustments			Pro Forma as Adjusted
	(in thousands)
Net change in prices and production costs	$	(109,214	)	$	—		$	(109,214	)
Purchases of minerals-in-place		81,304			—			81,304
Extensions, discoveries, and improved recovery		376,493			—			376,493
Revisions of previous quantity estimates		(189,505	)		—			(189,505	)
Production, net of production costs		(121,170	)		—			(121,170	)
Previously estimated development costs incurred during the period		119,361			—			119,361
Accretion of discount		59,144			—			59,144
Change in estimated future development costs		60,210			—			60,210
Net change in income taxes		(5,378	)		(95,776	)		(101,154	)
Change in timing and other		(1,488	)		—			(1,488	)
Net change in standardized measure		269,757			(95,776	)		173,981
Standardized measure, beginning of year		581,157			(152,652	)		428,505
Standardized measure, end of year	$	850,914		$	(248,428	)	$	602,486

F-14

ATHLON HOLDINGS LP
CONSOLIDATED BALANCE SHEETS
(in thousands)

	March 31, 2013			December 31, 2012
	(unaudited)
ASSETS
Current assets:
Cash and cash equivalents	$	3,379		$	8,871
Accounts receivable		33,149			24,501
Derivatives		—			2,246
Inventory		1,023			1,022
Other		781			2,486
Total current assets		38,332			39,126
Properties and equipment, at cost—full cost method:
Proved properties, including wells and related equipment		864,350			788,571
Unproved properties		95,892			89,860
Accumulated depletion, depreciation, and amortization		(91,829	)		(73,824	)
		868,413			804,607
Derivatives		2,204			2,854
Debt issuance costs		5,906			4,418
Other		1,680			1,293
Total assets	$	916,535		$	852,298
LIABILITIES AND PARTNERS' EQUITY
Current liabilities:
Accounts payable:
Trade	$	250		$	3,170
Affiliate		538			935
Accrued liabilities:
Lease operating		4,460			3,858
Production, severance, and ad valorem taxes		2,459			1,307
Development capital		29,986			39,483
Derivatives		4,599			592
Revenue payable		12,842			9,330
Other		3,232			2,700
Total current liabilities		58,366			61,375
Derivatives		324			519
Asset retirement obligations, net of current portion		5,600			5,049
Long-term debt		416,426			362,000
Other		2,489			2,478
Total liabilities		483,205			431,421
Commitments and contingencies
Partners' equity		433,330			420,877
Total liabilities and partners' equity	$	916,535		$	852,298

The accompanying notes are an integral part of these consolidated financial statements.

F-15

ATHLON HOLDINGS LP

CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands)

(unaudited)

	Three months ended March 31,
	2013		2012
Revenues:
Oil	$	45,659	$	27,433
Natural gas		3,367		1,448
Natural gas liquids		5,720		4,351
Total revenues		54,746		33,232
Expenses:
Production:
Lease operating		7,237		4,699
Production, severance, and ad valorem taxes		3,694		2,350
Depletion, depreciation, and amortization		18,053		9,614
General and administrative		3,339		2,597
Derivative fair value loss		6,849		22,711
Other operating		194		130
Total expenses		39,366		42,101
Operating income (loss)		15,380		(8,869	)
Interest expense		4,474		1,495
Income (loss) before income taxes		10,906		(10,364	)
Income tax provision (benefit)		27		(364	)
Net income (loss)	$	10,879	$	(10,000	)

The accompanying notes are an integral part of these consolidated financial statements.

F-16

ATHLON HOLDINGS LP

CONSOLIDATED STATEMENT OF CHANGES IN PARTNERS' EQUITY

(in thousands)

(unaudited)

	Total Partner's Equity
Balance at December 31, 2012	$	420,877
Capital contributions and equity-based compensation		1,574
Net income		10,879
Balance at March 31, 2013	$	433,330

The accompanying notes are an integral part of these consolidated financial statements.

F-17

ATHLON HOLDINGS LP

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

(unaudited)

	Three months ended March 31,
	2013			2012
Cash flows from operating activities:
Net income (loss)	$	10,879		$	(10,000	)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depletion, depreciation, and amortization		18,053			9,614
Deferred taxes		27			(364	)
Non-cash derivative loss		6,708			20,118
Equity-based compensation		48			58
Other		438			300
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable		(8,648	)		(3,021	)
Other current assets		219			319
Accounts payable		(2,253	)		4,712
Revenue payable		3,010			948
Other current liabilities		1,916			(1,961	)
Net cash provided by operating activities		30,397			20,723
Cash flows from investing activities:
Acquisitions of oil and natural gas properties		(8,819	)		(1,239	)
Development of oil and natural gas properties		(81,605	)		(57,120	)
Other		(136	)		(139	)
Net cash used in investing activities		(90,560	)		(58,498	)
Cash flows from financing activities:
Proceeds from long-term debt, net of issuance costs		53,271			21,816
Payments on long-term debt		—			(9,000	)
Other		1,400			166
Net cash provided by financing activities		54,671			12,982
Decrease in cash and cash equivalents		(5,492	)		(24,793	)
Cash and cash equivalents, beginning of period		8,871			32,030
Cash and cash equivalents, end of period	$	3,379		$	7,237

The accompanying notes are an integral part of these consolidated financial statements.

F-18

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

(unaudited)

Note 1. Formation of the Partnership and Description of Business

        Athlon Holdings LP (together with its subsidiaries, "Holdings"), a Delaware limited partnership, is an independent exploration and production company focused on the acquisition, development, and exploitation of unconventional oil and liquids-rich natural gas reserves in the Permian Basin. Holdings was formed on July 22, 2011, and is the holding company for Athlon Energy LP, a Delaware limited partnership, which was formed on August 5, 2010, and Athlon FE Energy LP, a Delaware limited partnership, which was formed on July 22, 2011. Athlon Holdings GP LLC serves as the general partner to Holdings with no obligations to make capital contributions and no rights to distributions.

        As of March 31, 2013, Holdings was a party to a limited partnership agreement with its management group and Apollo Athlon Holdings LLC ("Apollo"), which is an affiliate of Apollo Global Management, LLC. Apollo has a controlling influence over Holdings. As of March 31, 2013, Apollo Investment Fund VII, L.P. and its parallel funds (the "Apollo Funds"), members of Holdings' management team, and certain employees owned all of the Class A limited partner interests in Holdings and members of Holdings' management team and certain employees own all of the Class B limited partner interests in Holdings. Please read "Note 6. Partners' Equity" and "Note 7. Class B Limited Partner Interests" for additional discussion.

        Athlon Energy Inc. ("Athlon") was formed on April 1, 2013. On April 26, 2013, Holdings underwent a corporate reorganization and as a result, Athlon became the holding company of Holdings. Athlon will operate and control all of the business and affairs and consolidate the financial results of Holdings. In the reorganization, the Apollo Funds entered into a number of distribution and contribution transactions pursuant to which the Apollo Funds exchanged their Class A limited partner interests in Holdings for common stock of Athlon. The remaining holders of Class A limited partner interests in Holdings have not exchanged their interests in the reorganization transactions. In addition, the holders of the Class B limited partner interests in Holdings exchanged their interests for common stock of Athlon subject to the same vesting terms.

Note 2. Basis of Presentation

        Holdings' consolidated financial statements include the accounts of its wholly owned subsidiaries. All material intercompany balances and transactions have been eliminated in consolidation.

        In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments necessary to present fairly, in all material respects, Holdings financial position as of March 31, 2013 and results of operations and cash flows for the three months ended March 31, 2013 and 2012. All adjustments are of a normal recurring nature. These interim results are not necessarily indicative of results for an entire year.

        Certain amounts and disclosures have been condensed and omitted from the unaudited consolidated financial statements pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the "SEC"). Therefore, these unaudited consolidated financial statements should be read in conjunction with Holdings' audited consolidated financial statements and related notes thereto.

F-19

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 2. Basis of Presentation (Continued)

New Accounting Pronouncements

        In December 2011, the Financial Accounting Standards Board issued Accounting Standards Update ("ASU") 2011-11, "Disclosures about Offsetting Assets and Liabilities" and in January 2013 issued ASU 2013-01, "Clarifying the Scope of Disclosures About Offsetting Assets and Liabilities". These ASUs created new disclosure requirements regarding the nature of an entity's rights of setoff and related arrangements associated with its derivative instruments, repurchase agreements, and securities lending transactions. Certain disclosures of the amounts of certain instruments subject to enforceable master netting arrangements are required, irrespective of whether the entity has elected to offset those instruments in the statement of financial position. These ASUs were effective retrospectively for annual reporting periods beginning on or after January 1, 2013. The adoption of these ASUs did not impact Holdings' financial position, results of operations, or liquidity.

        No other new accounting pronouncements issued or effective during the three months ended March 31, 2013, or from March 31, 2013 through the date of this Report, had or are expected to have a material impact on Holdings' unaudited consolidated financial statements.

Note 3. Commitments and Contingencies

        Holdings is a party to ongoing legal proceedings in the ordinary course of business. Management does not believe the results of these proceedings, individually or in the aggregate, will have a material adverse effect on Holdings' business, financial position, results of operations, or liquidity.

        Additionally, Holdings has contractual obligations related to future plugging and abandonment expenses on oil and natural gas properties and related facilities disposal, long-term debt, commodity derivative contracts, operating leases, and development commitments.

Note 4. Asset Retirement Obligations

        Asset retirement obligations relate to future plugging and abandonment expenses on oil and natural gas properties and related facilities disposal. The following table summarizes the changes in Holdings' asset retirement obligations for the three months ended March 31, 2013 (in thousands):

Balance at January 1	$	5,049
Acquisition of properties		265
Wells drilled		253
Accretion of discount		149
Plugging and abandonment costs incurred		(9	)
Balance at March 31	$	5,707

        As of March 31, 2013, $5.6 million of Holdings' asset retirement obligations were long-term and recorded in "Asset retirement obligations, net of current portion" and $107,000 were current and included in "Other current liabilities" in the accompanying Consolidated Balance Sheets.

F-20

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 5. Long-Term Debt

Credit Agreement

        Holdings is a party to an amended and restated credit agreement dated March 19, 2013 (the "Holdings Credit Agreement"), which matures on March 19, 2018. The Holdings Credit Agreement provides for revolving credit loans to be made to Holdings from time to time and letters of credit to be issued from time to time for the account of Holdings or any of its restricted subsidiaries. The aggregate amount of the commitments of the lenders under the Holdings Credit Agreement is $1.0 billion. Availability under the Holdings Credit Agreement is subject to a borrowing base, which is redetermined semi-annually and upon requested special redeterminations. As of March 31, 2013, the borrowing base was $360 million and there were $291.4 million of outstanding borrowings, $68.6 million of borrowing capacity, and no outstanding letters of credit under the Holdings Credit Agreement.

        Obligations under the Holdings Credit Agreement are secured by a first-priority security interest in substantially all of Holdings' proved reserves and in the equity interests of its operating subsidiaries. In addition, obligations under the Holdings Credit Agreement are guaranteed by Holdings' operating subsidiaries.

        Loans under the Holdings Credit Agreement are subject to varying rates of interest based on (1) outstanding borrowings in relation to the borrowing base and (2) whether the loan is a Eurodollar loan or a base rate loan. Eurodollar loans under the Holdings Credit Agreement bear interest at the Eurodollar rate plus the applicable margin indicated in the following table, and base rate loans under the Holdings Credit Agreement bear interest at the base rate plus the applicable margin indicated in the following table. Holdings also incurs a quarterly commitment fee on the unused portion of the Holdings Credit Agreement indicated in the following table:

Ratio of Outstanding Borrowings to Borrowing Base	Unused Commitment Fee			Applicable Margin for Eurodollar Loans			Applicable Margin for Base Rate Loans
Less than or equal to .30 to 1		0.375	%		0.50	%		1.50	%
Greater than .30 to 1 but less than or equal to .60 to 1		0.375	%		0.75	%		1.75	%
Greater than .60 to 1 but less than or equal to .80 to 1		0.50	%		1.00	%		2.00	%
Greater than .80 to 1 but less than or equal to .90 to 1		0.50	%		1.25	%		2.25	%
Greater than .90 to 1		0.50	%		1.50	%		2.50	%

        The "Eurodollar rate" for any interest period (either one, two, three, or six months, as selected by Holdings) is the rate equal to the British Bankers Association London Interbank Offered Rate ("LIBOR") for deposits in dollars for a similar interest period. The "Base Rate" is calculated as the highest of: (1) the annual rate of interest announced by Bank of America, N.A. as its "prime rate"; (2) the federal funds effective rate plus 0.5%; or (3) except during a "LIBOR Unavailability Period", the Eurodollar rate (for dollar deposits for a one-month term) for such day plus 1.0%.

        Any outstanding letters of credit reduce the availability under the Holdings Credit Agreement. Borrowings under the Holdings Credit Agreement may be repaid from time to time without penalty.

        The Holdings Credit Agreement contains covenants including, among others, the following:

•

a prohibition against incurring debt, subject to permitted exceptions;

F-21

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 5. Long-Term Debt (Continued)

•

a restriction on creating liens on Holdings' assets and the assets of its operating subsidiaries, subject to permitted exceptions;

•

restrictions on merging and selling assets outside the ordinary course of business;

•

restrictions on use of proceeds, investments, transactions with affiliates, or change of principal business;

•

a requirement that Holdings maintain a ratio of consolidated funded debt to consolidated Adjusted EBITDA (as defined in the Holdings Credit Agreement) of not more than 4.75 to 1.0 beginning with the quarter ended June 30, 2013 (which ratio changes to 4.5 to 1.0 beginning with the quarter ended June 30, 2014); and

•

a provision limiting commodity derivative contracts to a volume not exceeding 85% of projected production from proved reserves for a period not exceeding 66 months from the date the swap is entered into.

        The Holdings Credit Agreement contains customary events of default, which would permit the lenders to accelerate the debt if not cured within applicable grace periods. If an event of default occurs and is continuing, lenders with a majority of the aggregate commitments may require Bank of America, N.A. to declare all amounts outstanding under the Holdings Credit Agreement to be immediately due and payable.

Second Lien

        As of March 31, 2013, Holdings was a party to a second lien term loan agreement dated September 5, 2012 (the "Second Lien"), which matures on November 21, 2017. The Second Lien provided for term loans to be made to Holdings in the aggregate amount of up to $125 million. As of March 31, 2013, there were $125 million outstanding loans under the Second Lien. Holdings used the net proceeds from the Second Lien to reduce outstanding borrowings under its credit agreement. The Second Lien was repaid in full with a portion of the net proceeds from the issuance of senior notes in April 2013. Please read "Note 10. Subsequent Events—Senior Notes" for additional discussion.

Note 6. Partners' Equity

        Holdings is party to a limited partnership agreement with its management group and Apollo. The Apollo Funds, members of Holdings' management team, and certain employees are Class A limited partners. The following table shows the partnership interest in Holdings as of March 31, 2013:

		Partnership Interest
Athlon Holdings LLC	General Partner		0.000	%
The Apollo Funds	Class A Partner		96.825	%
Management team and employees	Class A Partner		3.175	%

        As of March 31, 2013, Holdings had remaining capital commitments of approximately $38.1 million from the Apollo Funds and none from management and employees. After Holdings' corporate

F-22

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 6. Partners' Equity (Continued)

reorganization as discussed in "Note 10. Subsequent Events—Corporate Reorganization", the Apollo Funds have no further capital commitments.

Note 7. Class B Limited Partner Interests

        Holdings' limited partnership agreement provides for the issuance of Class B limited partner interests. The Class B interests entitle the holder to participate in the net profits of Holdings, but are subject to various performance criteria. Class A limited partners are entitled to a return of their initial investment plus interest compounded at 8% annually (the "Class A Preference Amount"). Upon the occurrence of a liquidity event and after the Class A Preference Amount has been satisfied, 80% and 20% of the remaining net profits will be distributed to holders of Class A interests and Class B interests, respectively. The Class B interests vest over four or five years or upon certain performance thresholds being met by Holdings. Class B interests can also vest on the occurrence of certain events such as a change in control or in some cases upon termination of employment with Holdings. The total number of Class B interests that may be issued pursuant to the partnership agreement is 100,000. As of March 31, 2013, there were 2,600 Class B interests available for issuance under the partnership agreement. Class B interests that are forfeited will again become available for issuance under the partnership agreement.

        Management has independent valuations prepared for its grants of Class B limited partner interests. During the three months ended March 31, 2013 and 2012, Holdings recorded approximately $48,000 and $58,000, respectively, of non-cash equity-based compensation expense, which was allocated to LOE and general and administrative expenses in the accompanying Consolidated Statements of Operations based on the allocation of the respective employees' compensation. During the three months ended March 31, 2013, Holdings also capitalized approximately $26,000 of non-cash stock-based compensation expense as a component of "Proved properties, including wells and related equipment" in the accompanying Consolidated Balance Sheets.

        The fair value of Class B interests granted was estimated on the grant date using an option pricing model based on the following assumptions for the periods indicated:

	Three months ended March 31,
	2013			2012
Expected volatility		40.6	%		46.3	%
Expected dividend yield		0	%		0	%
Expected term (in years)		0.62			1.63
Risk-free interest rate		0.13	%		0.24	%
Weighted-average grant date fair value per interest	$	67.68		$	140.72

        The expected volatility was calculated based on the average historical volatility of each company in Holdings' peer group based on historical stock price data. The expected term of the Class B interests was based on expected payout date from a triggering event. The risk-free interest rate was based on the U.S. Treasury yield curve in effect at the grant date for a period of time commensurate with the expected term of the Class B interests.

F-23

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 7. Class B Limited Partner Interests (Continued)

        The following table summarizes the changes in Holdings' Class B interests for the three months ended March 31, 2013:

	Number of Class B Interests			Weighted- Average Grant Date Fair Value
Outstanding at January 1		50,212		$	22.07
Granted		3,600			67.68
Vested		(7,175	)		6.36
Forfeited		—			—
Outstanding at March 31		46,637			27.65

        As of March 31, 2013, Holdings had approximately $1.2 million of total unrecognized compensation cost related to unvested Class B interests, which is expected to be recognized over a weighted-average period of approximately 3.8 years. During the three months ended March 31, 2013 and 2012, there were 7,175 and 6,832, respectively, Class B interests that vested, the total grant date fair value of which was approximately $46,000 and none, respectively.

        In conjunction with Holdings' corporate reorganization as discussed in "Note 10. Subsequent Events—Corporate Reorganization", the holders of the Class B limited partner interest in Holdings exchanged their interests for common stock of Athlon subject to the same vesting terms.

Note 8. Fair Value Measurements

        The book values of cash and cash equivalents, accounts receivable, and accounts payable approximate fair value due to the short-term nature of these instruments. The book values of the Holdings Credit Agreement and the Second Lien approximate fair value as the interest rates are variable. Holdings considers debt with variable interest rates to have a fair value equal to its carrying value ("Level 1" input). Commodity derivative contracts are marked-to-market each quarter and are thus stated at fair value in the accompanying Consolidated Balance Sheets.

Derivative Policy

        Holdings uses various financial instruments for non-trading purposes to manage and reduce price volatility and other market risks associated with its oil production. These arrangements are structured to reduce Holdings' exposure to commodity price decreases, but they can also limit the benefit Holdings might otherwise receive from commodity price increases. Holdings' risk management activity is generally accomplished through over-the-counter commodity derivative contracts with large financial institutions, most of which are lenders underwriting the Holdings Credit Agreement.

        Holdings applies the provisions of the "Derivatives and Hedging" topic of the Accounting Standards Codification, which requires each derivative instrument to be recorded in the accompanying Consolidated Balance Sheets at fair value. If a derivative has not been designated as a hedge or does not otherwise qualify for hedge accounting, it must be adjusted to fair value through earnings. Holdings elected not to designate its current portfolio of commodity derivative contracts as hedges. Therefore,

F-24

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 8. Fair Value Measurements (Continued)

changes in fair value of these derivative instruments are recognized in earnings and included in "Derivative fair value loss" in the accompanying Consolidated Statements of Operations.

Commodity Derivative Contracts

        Commodity prices are often subject to significant volatility due to many factors that are beyond Holdings' control, including but not limited to: prevailing economic conditions, supply and demand of hydrocarbons in the marketplace, actions by speculators, and geopolitical events such as wars or natural disasters. Holdings' objective is to manage its exposure to oil price risk with swaps, puts, and collars. Swaps provide a fixed price for a notional amount of sales volumes. Puts provide a fixed floor price on a notional amount of sales volumes while allowing full price participation if the relevant index price closes above the floor price. Collars provide a floor price on a notional amount of sales volumes while allowing some additional price participation if the relevant index price closes above the floor price. This participation is limited by a ceiling price specified in the contract.

        The following table summarizes open commodity derivative contracts as of March 31, 2013:

Period	Average Daily Floor Volume		Weighted- Average Floor Price		Average Daily Cap Volume		Weighted- Average Cap Price		Average Daily Swap Volume		Weighted- Average Swap Price		Asset (Liability) Fair Market Value
	(Bbl)		(per Bbl)		(Bbl)		(per Bbl)		(Bbl)		(per Bbl)		(in thousands)
Apr. - Dec. 2013		150	$	75.00		150	$	105.95		6,000	$	94.66	$	(3,474	)
2014		—		—		—		—		5,950		92.76		130
2015		—		—		—		—		1,300		93.18		1,782
													$	(1,562	)

        Holdings is also party to basis differential swaps for 5,000 Bbls/D at $1.20/Bbl for March through December 2013. At March 31, 2013, the fair value of these contracts was a liability of approximately $1.2 million.

        Counterparty Risk.    At March 31, 2013, Holdings had committed 10% or greater (in terms of fair market value) of its oil derivative contracts in asset positions from the following counterparties:

Counterparty	Fair Market Value of Oil Derivative Contracts Committed
	(in thousands)
BNP Paribas	$	1,824

        Holdings does not require collateral from its counterparties for entering into financial instruments, so in order to mitigate the credit risk associated with financial instruments, Holdings enters into master netting agreements with certain counterparties. The master netting agreement is a standardized, bilateral contract between a given counterparty and Holdings. Instead of treating each financial transaction between the counterparty and Holdings separately, the master netting agreement enables the counterparty and Holdings to aggregate all financial trades and treat them as a single agreement. This arrangement is intended to benefit Holdings in two ways: (1) default by a counterparty under one

F-25

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 8. Fair Value Measurements (Continued)

financial trade can trigger rights to terminate all financial trades with such counterparty; and (2) netting of settlement amounts reduces Holdings' credit exposure to a given counterparty in the event of close-out. Holdings' accounting policy is to not offset fair value amounts between different counterparties for derivative instruments in the accompanying Consolidated Balance Sheets.

Tabular Disclosures of Fair Value Measurements

        The following table summarizes the fair value of Holdings' derivative instruments not designated as hedging instruments as of the dates indicated:

Balance Sheet Location	Oil Commodity Derivatives			Commodity Derivatives Nettinga			Total Commodity Derivatives
As of March 31, 2013
Assets
Derivatives—current	$	863		$	(863	)	$	—
Derivatives—noncurrent		3,110			(906	)		2,204
Total assets		3,973			(1,769	)		2,204
Liabilities
Derivatives—current		(5,462	)		863			(4,599	)
Derivatives—noncurrent		(1,230	)		906			(324	)
Total liabilities		(6,692	)		1,769			(4,923	)
Net assets (liabilities)	$	(2,719	)	$	—		$	(2,719	)
As of December 31, 2012
Assets
Derivatives—current	$	3,386		$	(1,140	)	$	2,246
Derivatives—noncurrent		3,265			(411	)		2,854
Total assets		6,651			(1,551	)		5,100
Liabilities
Derivatives—current	$	(1,732	)		1,140		$	(592	)
Derivatives—noncurrent		(930	)		411			(519	)
Total liabilities		(2,662	)		1,551			(1,111	)
Net assets (liabilities)	$	3,989		$	—		$	3,989

^a

Represents counterparty netting under master netting agreements, which allow for netting of commodity derivative contracts. These derivative instruments are reflected net on the accompanying Consolidated Balance Sheets.

F-26

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 8. Fair Value Measurements (Continued)

        The following table summarizes the effect of derivative instruments not designated as hedges on the accompanying Consolidated Statements of Operations for the periods indicated (in thousands):

		Amount of Loss Recognized in Income
		Three months ended March 31,
	Location of Loss Recognized in Income
Derivatives Not Designated as Hedges		2013		2012
Commodity derivative contracts	Derivative fair value loss	$	6,849	$	22,711

Fair Value Hierarchy

        Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. GAAP establishes a three-tier fair value hierarchy, which prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are defined as follows:

•

Level 1—Inputs such as unadjusted, quoted prices that are available in active markets for identical assets or liabilities.

•

Level 2—Inputs, other than quoted prices within Level 1, that are either directly or indirectly observable.

•

Level 3—Inputs that are unobservable for use when little or no market data exists requiring the use of valuation methodologies that result in management's best estimate of fair value.

        As required by GAAP, Holdings utilizes the most observable inputs available for the valuation technique used. The financial assets and liabilities are classified in their entirety based on the lowest level of input that is of significance to the fair value measurement. Holdings' assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of the financial assets and liabilities and their placement within the fair value hierarchy levels. The following methods and assumptions were used to estimate the fair values of Holdings' assets and liabilities that are accounted for at fair value on a recurring basis:

•

Level 2—Fair values of swaps were estimated using a combined income-based and market-based valuation methodology based upon forward commodity price curves obtained from independent pricing services. Holdings' collars and puts are average value options. Settlement is determined by the average underlying price over a predetermined period of time. Holdings uses observable inputs in an option pricing valuation model to determine fair value such as: (1) current market and contractual prices for the underlying instruments; (2) quoted forward prices for oil and natural gas; (3) interest rates, such as a LIBOR curve for a term similar to the commodity derivative contract; and (4) appropriate volatilities.

        Holdings adjusts the valuations from the valuation model for nonperformance risk. For commodity derivative contracts which are in an asset position, Holdings uses the counterparty's credit default swap

F-27

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 8. Fair Value Measurements (Continued)

rating. For commodity derivative contracts which are in a liability position, Holdings uses the average credit default swap rating of its peer companies as Holdings does not have its own credit default swap rating. All fair values have been adjusted for nonperformance risk resulting in an increase in the net commodity derivative liability of approximately $0.2 million as of March 31, 2013 and an increase in the net commodity derivative asset of approximately $0.1 million as of December 31, 2012.

        The following table sets forth Holdings' assets and liabilities that were accounted for at fair value on a recurring basis as of the dates indicated:

				Fair Value Measurements at Reporting Date Using
Description	Asset (liability), net			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	(in thousands)
As of March 31, 2013
Oil derivative contracts—swaps	$	(1,504	)	$	—	$	(1,504	)	$	—
Oil derivative contracts—basis differential swaps		(1,157	)		—		(1,157	)		—
Oil derivative contracts—collars and puts		(58	)		—		(58	)		—
Total	$	(2,719	)	$	—	$	(2,719	)	$	—
As of December 31, 2012
Oil derivative contracts—swaps	$	4,069		$	—	$	4,069		$	—
Oil derivative contracts—collars and puts		(80	)		—		(80	)		—
Total	$	3,989		$	—	$	3,989		$	—

Note 9. Related Party Transactions

Transaction Fee Agreement

        Holdings is a party to a Transaction Fee Agreement, dated August 23, 2010, which requires Holdings to pay a fee to Apollo equal to 2% of the total equity contributed to Holdings, as defined in the agreement, in exchange for consulting and advisory services provided by Apollo. In October 2012, Apollo assigned its rights and obligations under the Transaction Fee Agreement to an affiliate, Apollo Global Securities, LLC. Since Holdings' inception through March 31, 2013, it has incurred transaction fees under the Transaction Fee Agreement of approximately $7.5 million in total. Upon the consummation of Athlon's initial public offering as discussed in "Note 10. Subsequent Events—Initial Public Offering", Holdings intends to terminate the Transaction Fee Agreement.

F-28

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 9. Related Party Transactions (Continued)

Services Agreement

        Holdings is a party to a Services Agreement, dated August 23, 2010, which requires Holdings to further compensate Apollo for consulting and advisory services equal to a minimum of $62,500 per quarter or 1% of net income before interest, income taxes, and DD&A, not to exceed $500,000 in any calendar year. The Services Agreement also provides for reimbursement to Apollo for any reasonable out-of-pocket expenses incurred while performing under the Services Agreement. During the three months ended March 31, 2013 and 2012, Holdings incurred approximately $405,000 and $213,000, respectively, of fees under the Services Agreement, which is included in "General and administrative expenses" in the accompanying Consolidated Statements of Operations.

        The Services Agreement provides that Apollo will provide advisory services until the earliest of (i) August 23, 2020, (ii) such time as Apollo owns in the aggregate less than 5% of the beneficial economic interest of Holdings, and (iii) such date as is mutually agreed upon by Holdings and Apollo. Upon the consummation of Athlon's initial public offering as discussed in "Note 10. Subsequent Events—Initial Public Offering", Holdings intends to terminate the Services Agreement and, in connection with the termination, Apollo will receive a discounted payment corresponding to the present value as of the date of termination of the aggregate annual fees that would have been payable during the remainder of the term of the Services Agreement (assuming a term ending on August 23, 2020). Under the Services Agreement, Holdings also agreed to indemnify Apollo and its affiliates and their respective limited partners, general partners, directors, members, officers, managers, employees, agents, advisors, their directors, officers, and representatives for potential losses relating to the services contemplated under the Services Agreement.

Note 10. Subsequent Events

Senior Notes

        In April 2013, Holdings issued $500 million aggregate principal amount of 7³/8% senior notes due 2021. The net proceeds from the senior notes offering were used to repay a portion of the outstanding borrowings under the Holdings Credit Agreement, to repay the Second Lien in full, to make a $75 million distribution to Holdings' Class A limited partners, and for general partnership purposes. The indenture governing the senior notes contains covenants, including, among other things, covenants that restrict Holdings' ability to:

•

make distributions, investments, or other restricted payments if Holdings' fixed charge coverage ratio is less than 2.0 to 1.0;

•

incur additional indebtedness if Holdings' fixed charge coverage ratio would be less than 2.0 to 1.0; and

•

create liens, sell assets, consolidate or merge with any other person, or engage in transactions with affiliates.

These covenants are subject to a number of important qualifications, limitations, and exceptions. In addition, the indenture contains other customary terms, including certain events of default upon the occurrence of which the senior notes may be declared immediately due and payable.

F-29

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 10. Subsequent Events (Continued)

        Under the indenture, starting on April 15, 2016, Holdings will be able to redeem some or all of the senior notes at a premium that will decrease over time, plus accrued and unpaid interest to the date of redemption. Prior to April 15, 2016, Holdings will be able, at its option, to redeem up to 35% of the aggregate principal amount of the senior notes at a price of 107.375% of the principal thereof, plus accrued and unpaid interest to the date of redemption, with an amount equal to the net proceeds from certain equity offerings. In addition, at Holdings' option, prior to April 15, 2016, Holdings may redeem some or all of the senior notes at a redemption price equal to 100% of the principal amount of the senior notes, plus an "applicable premium", plus accrued and unpaid interest to the date of redemption. If a change of control occurs on or prior to July 15, 2014, Holdings may redeem all, but not less than all, of the notes at 110% of the principal amount thereof plus accrued and unpaid interest to, but not including, the redemption date. Certain asset dispositions will be triggering events that may require Holdings to repurchase all or any part of a noteholder's notes at a purchase price in cash equal to 101% of the principal amount thereof, plus accrued and unpaid interest, if any, to but excluding the date of repurchase. Interest on the senior notes is payable in cash semi-annually in arrears, commencing on October 15, 2013, through maturity.

Holdings Credit Agreement

        In conjunction with the offering of senior notes, the borrowing base under the Holdings Credit Agreement was reduced to $267.5 million. Holdings used a portion of the net proceeds from the offering of the senior notes as discussed above to reduce the outstanding borrowings under the Holdings Credit Agreement. As of May 15, 2013, there were $36 million of outstanding borrowings under the Holdings Credit Agreement.

Corporate Reorganization

        As previously discussed in "Note 1. Formation of the Partnership and Description of Business", Athlon was formed on April 1, 2013. On April 26, 2013, Holdings underwent a corporate reorganization and as a result, Athlon became the holding company of Holdings. Athlon will operate and control all of the business and affairs and consolidate the financial results of Holdings. In the corporate reorganization, the Apollo Funds entered into a number of distribution and contribution transactions pursuant to which the Apollo Funds exchanged their Class A limited partner interests in Holdings for common stock of Athlon. The remaining holders of Class A limited partner interests in Holdings have not exchanged their interests in the reorganization transactions. In addition, the holders of the Class B limited partner interests in Holdings exchanged their interests for common stock of Athlon subject to the same vesting terms. As a result of the corporate reorganization, Athlon has become a taxable entity for federal income tax purposes. Management is in the process of computing the tax-related impacts of the corporate reorganization.

Initial Public Offering

        On April 29, 2013, Athlon announced that it has confidentially submitted a draft registration statement on Form S-1 to the SEC for a possible initial public offering of shares of its common stock. The number of shares to be offered and the price range for the offering have not yet been determined. Athlon intends to contribute the proceeds from the initial public offering to Holdings, which is

F-30

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

(unaudited)

Note 10. Subsequent Events (Continued)

expected to use the proceeds to reduce outstanding borrowings under the Holdings Credit Agreement, to provide additional liquidity for use in its drilling program, and for general corporate purposes, including potential acquisitions. The initial public offering is expected to commence after the SEC completes the review process with respect to Athlon's registration statement, subject to market conditions and other conditions.

        These financial statements considered subsequent events through May 15, 2013, the date the consolidated financial statements were available to be issued.

F-31

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Supervisors and Partners
Athlon Holdings LP

        We have audited the accompanying consolidated balance sheets of Athlon Holdings LP (the "Partnership") as of December 31, 2012 and 2011, and the related consolidated statements of operations, changes in partners' equity, and cash flows for each of the two years in the period ended December 31, 2012. These financial statements are the responsibility of the Partnership's management. Our responsibility is to express an opinion on these financial statements based on our audits.

        We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. We were not engaged to perform an audit of the Partnership's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Partnership's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

        In our opinion, the financial statements referred to above present fairly, in all material respects, the consolidated financial position of Athlon Holdings LP at December 31, 2012 and 2011, and the consolidated results of its operations and its cash flows for each of the two years in the period ended December 31, 2012, in conformity with U.S. generally accepted accounting principles.

/s/ Ernst & Young LLP

Fort Worth, Texas
March 8, 2013

F-32

ATHLON HOLDINGS LP

CONSOLIDATED BALANCE SHEETS

(in thousands)

	December 31,
	2012			2011
ASSETS
Current assets:
Cash and cash equivalents	$	8,871		$	32,030
Accounts receivable		24,501			17,181
Derivatives		2,246			—
Inventory		1,022			751
Other		2,486			1,574
Total current assets		39,126			51,536
Properties and equipment, at cost—full cost method:
Proved properties, including wells and related equipment		788,571			399,205
Unproved properties		89,860			125,036
Accumulated depletion, depreciation, and amortization		(73,824	)		(19,589	)
		804,607			504,652
Derivatives		2,854			2,503
Debt issuance costs		4,418			2,264
Other		1,293			868
Total assets	$	852,298		$	561,823
LIABILITIES AND PARTNERS' EQUITY
Current liabilities:
Accounts payable:
Trade	$	3,170		$	3,214
Affiliate		935			4,581
Accrued liabilities:
Lease operating		3,858			2,568
Production, severance, and ad valorem taxes		1,307			2,592
Development capital		39,483			30,863
Derivatives		592			5,908
Revenue payable		9,330			5,710
Other		2,700			2,036
Total current liabilities		61,375			57,472
Derivatives		519			2,554
Asset retirement obligations		5,049			3,704
Long-term debt		362,000			170,000
Other		2,478			641
Total liabilities		431,421			234,371
Commitments and contingencies
Partners' equity		420,877			327,452
Total liabilities and partners' equity	$	852,298		$	561,823

The accompanying notes are an integral part of these consolidated financial statements.

F-33

ATHLON HOLDINGS LP

CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands)

	Year ended December 31,
	2012			2011
Revenues:
Oil	$	128,081		$	51,193
Natural gas		8,415			3,521
Natural gas liquids		20,615			10,967
Total revenues		157,111			65,681
Expenses:
Production:
Lease operating		25,503			13,328
Production, severance, and ad valorem taxes		10,438			4,727
Depletion, depreciation, and amortization		54,456			19,747
General and administrative		9,678			7,724
Acquisition costs		876			9,519
Derivative fair value loss (gain)		(9,293	)		7,959
Other operating		562			404
Total expenses		92,220			63,408
Operating income		64,891			2,273
Interest expense		9,949			2,932
Income (loss) before income taxes		54,942			(659	)
Income tax provision		1,928			470
Net income (loss)	$	53,014		$	(1,129	)

The accompanying notes are an integral part of these consolidated financial statements.

F-34

ATHLON HOLDINGS LP

CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' EQUITY

(in thousands)

	Total Partners' Equity
Balance at December 31, 2010	$	24,499
Capital contributions from partners		303,976
Equity-based compensation		106
Net loss		(1,129	)
Balance at December 31, 2011		327,452
Capital contributions from partners		40,166
Equity-based compensation		245
Net income		53,014
Balance at December 31, 2012	$	420,877

The accompanying notes are an integral part of these consolidated financial statements.

F-35

ATHLON HOLDINGS LP

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

	Year ended December 31,
	2012			2011
Cash flows from operating activities:
Net income (loss)	$	53,014		$	(1,129	)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depletion, depreciation, and amortization		54,456			19,747
Deferred taxes		1,928			470
Non-cash derivative loss (gain)		(9,947	)		7,509
Equity-based compensation		152			106
Other		1,758			963
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable		(7,320	)		(16,963	)
Other current assets		(337	)		(1,691	)
Other assets		—			(16	)
Accounts payable		(2,140	)		537
Revenue payable		3,620			5,710
Derivatives		—			(1,950	)
Other current liabilities		118			5,579
Net cash provided by operating activities		95,302			18,872
Cash flows from investing activities:
Acquisitions of oil and natural gas properties		(80,602	)		(414,759	)
Development of oil and natural gas properties		(266,235	)		(57,457	)
Monetization of put options		—			7,625
Other		(422	)		(884	)
Net cash used in investing activities		(347,259	)		(465,475	)
Cash flows from financing activities:
Proceeds from long-term debt, net of issuance costs		519,672			198,651
Payments on long-term debt		(331,000	)		(31,000	)
Capital contributions from partners		40,166			303,976
Other		(40	)		—
Net cash provided by financing activities		228,798			471,627
Increase (decrease) in cash and cash equivalents		(23,159	)		25,024
Cash and cash equivalents, beginning of period		32,030			7,006
Cash and cash equivalents, end of period	$	8,871		$	32,030

The accompanying notes are an integral part of these consolidated financial statements.

F-36

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

Note 1. Formation of the Partnership and Description of Business

        Athlon Holdings LP (together with its subsidiaries, "Holdings"), a Delaware limited partnership, is engaged in the acquisition and development of oil and natural gas reserves in the Permian Basin of West Texas. Holdings was formed on July 22, 2011, and is the holding company for Athlon Energy LP (together with its operating subsidiary, Athlon Energy Operating LLC, "Athlon SG"), a Delaware limited partnership, which was formed on August 5, 2010, and Athlon FE Energy LP (together with its operating subsidiary, Athlon FE Operating LLC, "Athlon FE"), a Delaware limited partnership, which was formed on July 22, 2011. Athlon Holdings LLC serves as the general partner to Holdings with no obligations to make capital contributions and no rights to distributions. Holdings owns all of Athlon SG's and Athlon FE's general partner and limited partner units.

        On August 23, 2010, Athlon SG entered into a limited partnership agreement with its management group and Apollo Athlon Holdings LLC ("Apollo"), which is an affiliate of Apollo Global Management, LLC. Apollo has a controlling influence over Holdings. On July 22, 2011, the partnership agreement was amended and restated resulting in the formation of Holdings and Athlon FE. Upon formation, Holdings became the holding company of Athlon SG and Athlon FE. The amended and restated partnership agreement required all of Athlon SG's equity contributions to be contributed to Holdings. The holders of all Class A and Class B limited partner units in Athlon SG contributed these units to Holdings in exchange for equivalent units of Holdings. As the amendment of the partnership agreement constituted a reorganization of entities under common control, the operations of Athlon SG are presented as if Holdings existed and owned Athlon SG prior to July 22, 2011 and the assets and liabilities of Athlon SG are reflected at their carrying amounts. Please read "Note 7. Partners' Equity" and "Note 8. Employee Benefit Plans" for additional discussion.

Note 2. Summary of Significant Accounting Policies

Principles of Consolidation

        Holdings' consolidated financial statements include the accounts of its wholly owned subsidiaries. All material intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

        Preparing financial statements in conformity with accounting principles generally accepted in the United States requires management to make certain estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, and expenses, and the disclosure of contingent assets and liabilities in the consolidated financial statements. Although management believes these estimates are reasonable, actual results could differ materially from those estimates.

        Estimates made in preparing these consolidated financial statements include, among other things, estimates of the proved oil and natural gas reserve volumes used in calculating depletion, depreciation, and amortization ("DD&A") expense; operating costs accrued; volumes and prices for revenues accrued; valuation of derivative instruments; and the timing and amount of future abandonment costs used in calculating asset retirement obligations. Changes in the assumptions used could have a significant impact on results in future periods.

F-37

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

Cash and Cash Equivalents

        Cash and cash equivalents include demand deposits and funds invested in highly liquid instruments with original maturities of three months or less and typically exceed federally insured limits.

        The following table sets forth supplemental disclosures of cash flow information for the periods indicated:

	Year ended December 31,
	2012		2011
	(in thousands)
Cash paid during the period for:
Interest	$	8,326	$	2,395
Income taxes		—		—

Accounts Receivable

        Accounts receivable, which are primarily from the sale of oil, natural gas, and natural gas liquids ("NGLs"), is accrued based on estimates of the sales and prices Holdings believes it will receive. Holdings routinely reviews outstanding balances, assesses the financial strength of its customers, and records a reserve for amounts not expected to be fully recovered. Actual balances are not applied against the reserve until substantially all collection efforts have been exhausted. At December 31, 2012 and 2011, Holdings had no allowance for doubtful accounts.

Inventory

        Inventory includes materials and supplies that Holdings intends to deploy to various development activities and oil in tanks at the lease, both of which are stated at the lower of cost (determined on an average basis) or market. Oil in tanks at the lease is carried at an amount equal to its costs to produce. Inventory consisted of the following as of the dates indicated:

	December 31,
	2012		2011
	(in thousands)
Materials and supplies	$	670	$	371
Oil inventory		352		380
Total inventory	$	1,022	$	751

Oil and Natural Gas Properties

        Holdings applies the provisions of the "Extractive Activities—Oil and Gas" topic of the Financial Accounting Standards Board's (the "FASB") Accounting Standards Codification (the "ASC"). Holdings uses the full cost method of accounting for its oil and natural gas properties. Under this method, costs directly associated with the acquisition, exploration, and development of reserves are capitalized into a full cost pool. Capitalized costs are amortized using a unit-of-production method. Under this method, the provision for DD&A is computed at the end of each period by multiplying total production for the

F-38

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

period by a depletion rate. The depletion rate is determined by dividing the total unamortized cost base plus future development costs by net equivalent proved reserves at the beginning of the period.

        Costs associated with unproved properties are excluded from the amortizable cost base until a determination has been made as to the existence of proved reserves. Unproved properties are reviewed at the end of each quarter to determine whether the costs incurred should be reclassified to the full cost pool and, thereby, subjected to amortization. The costs associated with unproved properties primarily consist of acquisition and leasehold costs as well as development costs for wells in progress for which a determination of the existence of proved reserves has not been made. These costs are transferred to the amortization base once a determination is made whether or not proved reserves can be assigned to the property, upon impairment of a lease, or immediately upon determination that the well is unsuccessful. Costs of seismic data that cannot be directly associated to specific unproved properties are included in the full cost pool as incurred, otherwise, they are allocated to various unproved leaseholds and transferred to the amortization base with the associated leasehold costs on a specific project basis.

        Unevaluated properties are assessed periodically, at least annually, for possible impairment. Properties are assessed on an individual basis or as a group if properties are individually insignificant. The assessment includes consideration of various factors, including, but not limited to: intent to drill, remaining lease term, geological and geophysical evaluations, drilling results, and economic viability of development if proved reserves are assigned. During any period in which these factors indicate impairment, the cumulative drilling costs incurred to date for such property and all or a portion of the associated leasehold costs are transferred to the full cost pool and become subject to amortization.

        Under the full cost method of accounting, total capitalized costs of oil and natural gas properties, net of accumulated depletion, less related deferred income taxes may not exceed an amount equal to the present value of future net revenues from proved reserves, discounted at 10% per annum, plus the lower of cost or fair value of unevaluated properties, plus estimated salvage value, less the related tax effects (the "ceiling limitation"). A ceiling limitation is calculated at the end of each quarter. If total capitalized costs, net of accumulated DD&A, less related deferred income taxes are greater than the ceiling limitation, a write-down or impairment of the full cost pool is required. A write-down of the carrying value of the full cost pool is a non-cash charge that reduces earnings and impacts partners' equity in the period of occurrence and typically results in lower DD&A expense in future periods. Once incurred, a write-down cannot be reversed at a later date.

        The ceiling limitation calculation is prepared using the 12-month first-day-of-the-month oil and natural gas average prices, as adjusted for basis or location differentials, held constant over the life of the reserves ("net wellhead prices"). If applicable, these net wellhead prices would be further adjusted to include the effects of any fixed price arrangements for the sale of oil and natural gas. Holdings uses commodity derivative contracts to mitigate the risk against the volatility of oil and natural gas prices. Commodity derivative contracts that qualify and are designated as cash flow hedges are included in estimated future cash flows. Holdings has not designated any of its commodity derivative contracts as cash flow hedges and has therefore not included its commodity derivative contracts in estimating future cash flows. The future cash outflows associated with future development or abandonment of wells are included in the computation of the discounted present value of future net revenues for purposes of the ceiling limitation calculation.

F-39

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

        Sales and abandonments of oil and natural gas properties being amortized are accounted for as adjustments to the full cost pool, with no gain or loss recognized, unless the adjustments would significantly alter the relationship between capitalized costs and proved reserves. A significant alteration would not ordinarily be expected to occur upon the sale of reserves involving less than 25% of the reserve quantities of a cost center.

        Natural gas volumes are converted to barrels of oil equivalent ("BOE") at the rate of six thousand cubic feet ("Mcf") of natural gas to one barrel ("Bbl") of oil. This convention is not an equivalent price basis and there may be a large difference in value between an equivalent volume of oil versus an equivalent volume of natural gas.

        Independent petroleum engineers estimate Holdings' proved reserves annually on December 31. This results in a new DD&A rate which Holdings uses for the preceding fourth quarter after adjusting for fourth quarter production. Holdings internally estimates reserve additions and reclassifications of reserves from unproved to proved at the end of the first, second, and third quarters for use in determining a DD&A rate for the respective quarter.

        Holdings capitalizes interest on expenditures made in connection with exploration and development projects that are not subject to current amortization. Interest is capitalized only for the period that activities are in progress to bring these projects to their intended use. Capitalized interest cannot exceed gross interest expense. During 2012, Holdings capitalized approximately $0.2 million of interest expense. During 2011, Holdings did not capitalize any interest expense.

        Amounts shown in the accompanying Consolidated Balance Sheets as "Proved properties, including wells and related equipment" consisted of the following as of the date indicated:

	December 31,
	2012		2011
	(in thousands)
Proved leasehold costs	$	376,271	$	283,302
Wells and related equipment—completed		379,036		89,140
Wells and related equipment—in process		33,264		26,763
Total proved properties	$	788,571	$	399,205

Asset Retirement Obligations

        Holdings applies the provisions of the "Asset Retirement and Environmental Obligations" topic of the ASC. Holdings has obligations as a result of lease agreements and enacted laws to remove its equipment and restore land at the end of production operations. These asset retirement obligations are primarily associated with plugging and abandoning wells and land remediation. At the time a well is drilled or acquired, Holdings records a separate liability for the estimated fair value of its asset retirement obligations, with an offsetting increase to the related oil and natural gas asset representing asset retirement costs in the accompanying Consolidated Balance Sheets. The cost of the related oil and natural gas asset, including the asset retirement cost, is included in Holdings' full cost pool. The estimated fair value of an asset retirement obligation is the present value of the expected future cash outflows required to satisfy the asset retirement obligations discounted at Holdings' credit-adjusted,

F-40

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

risk-free interest rate at the time the liability is incurred. Accretion expense is recognized over time as the discounted liability is accreted to its expected settlement value.

        Inherent to the present-value calculation are numerous estimates, assumptions, and judgments, including, but not limited to: the ultimate settlement amounts, inflation factors, credit-adjusted risk-free rates, timing of settlement, and changes in the legal, regulatory, environmental, and political environments. To the extent future revisions to these assumptions affect the present value of the abandonment liability, Holdings makes corresponding adjustments to both the asset retirement obligation and the related oil and natural gas property asset balance. These revisions result in prospective changes to DD&A expense and accretion of the discounted abandonment liability. Please read "Note 5. Asset Retirement Obligations" for additional information.

Segment Reporting

        Holdings operates in only one industry: the oil and natural gas exploration and production industry in the United States. All revenues are derived from customers located in the United States.

Major Customers/Concentration of Credit Risk

        The following purchasers accounted for 10% or greater of the sales of production for the periods indicated and the corresponding outstanding accounts receivable balance as of the dates indicated:

	Percentage of Total Revenues for the Year Ended December 31,						Outstanding Accounts Receivable Balance as of December 31,
Purchaser	2012			2011			2012		2011
							(in thousands)
Occidental Petroleum Corporation		29	%		58	%	$	4,456	$	5,863
DCP Midstream		12	%		13	%		2,604		2,716
Pecos Gathering & Marketing		43	%		13	%		9,348		3,756

Income Taxes

        Holdings is treated as a partnership for federal and state income tax purposes with each partner being separately taxed on their share of Holdings' taxable income. Therefore, no provision for current or deferred federal income taxes has been provided for in the accompanying Consolidated Financial Statements. However, Holdings' operations located in Texas are subject to an entity-level tax, the Texas margin tax, at a statutory rate of up to 0.7% of income that is apportioned to Texas. Deferred tax assets and liabilities are recognized for future Texas margin tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective Texas margin tax bases.

        Net income (loss) for financial statement purposes may differ significantly from taxable income reportable to partners as a result of differences between the tax bases and financial reporting bases of assets and liabilities and the taxable income allocation requirements under the partnership agreement. In addition, individual partners have different investment bases depending upon the timing and price of acquisition of their partnership units, and each partner's tax accounting, which is partially dependent

F-41

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

upon the partner's tax position, differs from the accounting followed in the accompanying Consolidated Financial Statements. As a result, the aggregate difference in the basis of net assets for financial and tax reporting purposes cannot be readily determined as Holdings does not have access to information about each partner's tax attributes in Holdings.

        Holdings performs a periodic evaluation of tax positions to review the appropriate recognition threshold for each tax position recognized in its consolidated financial statements. As of December 31, 2012 and 2011, all of Holdings' tax positions met the "more-likely-than-not" threshold. As a result, no additional tax expense, interest, or penalties have been accrued.

Revenue Recognition

        Revenues from the sale of oil, natural gas and NGLs are recognized when the production is sold, net of any royalty interest. Because final settlement of Holdings' hydrocarbon sales can take up to two months, the expected sales volumes and prices for those properties are estimated and accrued using information available at the time the revenue is recorded. Natural gas revenues are recorded using the sales method of accounting whereby revenue is recognized based on actual sales of natural gas rather than Holdings' proportionate share of natural gas production. If Holdings' overproduced imbalance position (i.e., Holdings has cumulatively been over-allocated production) is greater than its share of remaining reserves, a liability would be recorded for the excess at period-end prices unless a different price is specified in the contract, in which case that price is used. At December 31, 2012 and 2011, Holdings did not have any natural gas imbalances. Revenue is not recognized for oil production in tanks, but the production is recorded as a current asset based on the cost to produce and included in "Inventory" in the accompanying Consolidated Balance Sheets. Transportation expenses are included in operating expenses and are not material.

Derivatives

        Holdings uses various financial instruments for non-trading purposes to manage and reduce price volatility and other market risks associated with its oil production. These arrangements are structured to reduce Holdings' exposure to commodity price decreases, but they can also limit the benefit Holdings might otherwise receive from commodity price increases. Holdings' risk management activity is generally accomplished through over-the-counter commodity derivative contracts with large financial institutions, most of which are lenders underwriting Holdings' revolving credit agreement.

        Holdings applies the provisions of the "Derivatives and Hedging" topic of the ASC, which requires each derivative instrument to be recorded in the accompanying Consolidated Balance Sheets at fair value. If a derivative has not been designated as a hedge or does not otherwise qualify for hedge accounting, it must be adjusted to fair value through earnings. Holdings elected not to designate its current portfolio of commodity derivative contracts as hedges. Therefore, changes in fair value of these derivative instruments are recognized in earnings and included in "Derivative fair value loss (gain)" in the accompanying Consolidated Statements of Operations.

New Accounting Pronouncements

        In May 2011, the FASB issued Accounting Standards Update ("ASU") 2011-04, "Amendments to Achieve Common Fair Value Measurements and Disclosure Requirements in U.S. GAAP and IFRSs". ASU 2011-04 amended ASC 820 to converge the fair value measurement guidance in GAAP and

F-42

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

International Financial Reporting Standards. Certain of the amendments clarified the application of existing fair value measurement requirements, while other amendments changed a particular principle in ASC 820. In addition, ASU 2011-04 required additional fair value disclosures. The amendments were effective for annual periods beginning after December 15, 2011. The adoption of ASU 2011-04 did not have a material impact on Holdings' financial position, results of operations, or liquidity.

        In December 2011, the FASB issued ASU 2011-11, "Disclosures about Offsetting Assets and Liabilities" and in January 2013 issued ASU 2013-01, "Clarifying the Scope of Disclosures About Offsetting Assets and Liabilities". These ASUs create new disclosure requirements regarding the nature of an entity's rights of setoff and related arrangements associated with its derivative instruments, repurchase agreements, and securities lending transactions. Certain disclosures of the amounts of certain instruments subject to enforceable master netting arrangements would be required, irrespective of whether the entity has elected to offset those instruments in the statement of financial position. These ASUs are effective retrospectively for annual reporting periods beginning on or after January 1, 2013. The adoption of these ASUs will not impact Holdings' financial position, results of operations, or liquidity.

        No other new accounting pronouncements issued or effective during 2012, or in 2013 through the date of this report, had or are expected to have a material impact on Holdings' consolidated financial statements.

Note 3. Acquisitions

Cobra

        In December 2012, Athlon FE acquired certain oil and natural gas properties and related assets in the Permian Basin in West Texas from Cobra Oil & Gas Corporation and certain of its subsidiaries and affiliates for approximately $48.3 million in cash, which was financed through a $40 million capital contribution from Apollo and borrowings under Holdings' credit agreement. The operations of these properties have been included with those of Athlon FE from the date of acquisition.

Element

        On October 3, 2011, Athlon FE acquired certain oil and natural gas properties and related assets in the Permian Basin in West Texas from Element Petroleum, LP ("Element") for approximately $253.2 million in cash, which was financed through borrowings under Athlon FE's then-existing credit agreement and capital contributions from partners. The operations of these properties have been included with those of Athlon FE from the date of acquisition. Athlon FE incurred approximately $6.4 million of transaction costs related to this acquisition, which are included in "General and administrative expenses" in the accompanying Consolidated Statements of Operations. Of this amount, approximately $4.3 million was paid to Apollo. Please read "Note 10. Related Party Transactions" for additional discussion.

F-43

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 3. Acquisitions (Continued)

        The allocation of the purchase price to the fair value of the assets acquired and liabilities assumed from Element was as follows (in thousands):

Proved properties, including wells and related equipment	$	130,527
Unproved properties		123,107
Other assets		806
Total assets acquired		254,440
Current liabilities		831
Asset retirement obligations		393
Total liabilities assumed		1,224
Fair value of net assets acquired	$	253,216

Pro Formas

        The following unaudited pro forma condensed financial data was derived from the historical financial statements of Holdings and from the accounting records of Element to give effect to the acquisition as if it had occurred on January 1, 2011. The unaudited pro forma condensed financial information has been included for comparative purposes only and is not necessarily indicative of the results that might have occurred had the Element acquisition taken place on January 1, 2011 and is not intended to be a projection of future results.

	Year ended December 31, 2011
	(in thousands)
Pro forma total revenues	$	89,618
Pro forma net income	$	9,777

SandRidge

        On January 6, 2011, Athlon SG acquired certain oil and natural gas properties and related assets in the Permian Basin in West Texas from SandRidge Exploration and Production, LLC ("SandRidge") for approximately $156.0 million in cash, which was financed through borrowings under Athlon SG's then-existing credit agreement and capital contributions from partners. The operations of these properties have been included with those of Athlon SG from the date of acquisition. Athlon SG incurred $2.6 million of transaction costs related to this acquisition, which are included in "General and administrative expenses" in the accompanying Consolidated Statements of Operations. Of this amount, approximately $2.3 million was paid to Apollo. Please read "Note 10. Related Party Transactions" for additional discussion.

F-44

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 3. Acquisitions (Continued)

        The allocation of the purchase price to the fair value of the assets acquired and liabilities assumed from SandRidge was as follows (in thousands):

Proved properties, including wells and related equipment	$	158,157
Oil inventory		637
Total assets acquired		158,794
Asset retirement obligations		2,778
Fair value of net assets acquired	$	156,016

Note 4. Commitments and Contingencies

Leases

        Holdings leases certain office space that has non-cancelable lease terms in excess of one year. The following table summarizes by year the remaining non-cancelable future payments under these operating leases as of December 31, 2012:

	Payments Due by Period
	Total		2013		2014		2015		2016		2017		Thereafter
	(in thousands)
Corporate office lease	$	1,412	$	381	$	375	$	375	$	281	$	—	$	—
Midland office lease		375		90		92		96		97		—		—
Total	$	1,787	$	471	$	467	$	471	$	378	$	—	$	—

        Holdings' operating lease rental expense was approximately $507 thousand and $272 thousand during 2012 and 2011, respectively.

Litigation

        Holdings is a party to ongoing legal proceedings in the ordinary course of business. Management does not believe the results of these proceedings, individually or in the aggregate, will have a material adverse effect on Holdings' business, financial position, results of operations, or liquidity.

F-45

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 5. Asset Retirement Obligations

        Asset retirement obligations relate to future plugging and abandonment expenses on oil and natural gas properties and related facilities disposal. The following table summarizes the changes in Holdings' asset retirement obligations for the period indicated:

	Year Ended December 31,
	2012			2011
	(in thousands)
Balance at January 1	$	3,704		$	—
Acquisition of properties		60			3,282
Wells drilled		815			166
Accretion of discount		478			344
Revisions of previous estimates		(8	)		—
Plugging and abandonment costs incurred		—			(88	)
Balance at December 31	$	5,049		$	3,704

Note 6. Long-Term Debt

Second Lien

        Holdings is a party to a second lien term loan agreement dated September 5, 2012 (the "Second Lien"), which matures on November 21, 2017. The Second Lien provides for term loans to be made to Holdings in the aggregate amount of up to $125 million. At December 31, 2012, there were $125 million outstanding loans under the Second Lien. Holdings used the net proceeds from the Second Lien to reduce outstanding borrowings under its credit agreements.

        Obligations under the Second Lien are secured by a second-priority security interest in substantially all of Holdings' proved reserves and in the equity interests of its operating subsidiaries. In addition, obligations under the Second Lien are fully and unconditionally guaranteed by Holdings' operating subsidiaries.

        Loans under the Second Lien are subject to varying rates of interest based on whether the loan is a Eurodollar loan or a base rate loan. Eurodollar loans under the Second Lien bear interest at the Eurodollar rate plus the applicable margin indicated in the following table, and base rate loans under the Second Lien bear interest at the base rate plus the applicable margin indicated in the following table:

Period	Eurodollar Loans			Base Rate Loans
September 5, 2012 through December 31, 2013		6.50	%		5.50	%
January 1, 2014 through December 31, 2014		6.75	%		5.75	%
January 1, 2015 through December 31, 2015		7.00	%		6.00	%
January 1, 2016 and thereafter		7.25	%		6.25	%

        The "Eurodollar rate" for any interest period (either one, two, three, or six months, as selected by Holdings) is equal to the British Bankers Association London Interbank Offered Rate ("LIBOR") divided by 1.00 minus the rate prescribed by the Board of Governors of the Federal Reserve System for determining the maximum reserve requirements in respect of Eurocurrency liabilities for a member of

F-46

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 6. Long-Term Debt (Continued)

the Federal Reserve System in New York City. The "Base Rate" is calculated as the highest of: (1) the annual rate of interest announced by Wells Fargo Bank, N.A. as its "prime rate"; (2) the federal funds effective rate plus 0.5%; or (3) LIBOR plus 1.0%.

        Borrowings under the Second Lien may be repaid from time to time without penalty, except during 2015 in which case there is a 1.0% pre-payment fee.

        The Second Lien contains covenants including, among others, the following:

•

a prohibition against incurring debt, subject to permitted exceptions;

•

a restriction on creating liens on Holdings' assets and the assets of its operating subsidiaries, subject to permitted exceptions;

•

restrictions on merging and selling assets outside the ordinary course of business;

•

restrictions on use of proceeds, investments, transactions with affiliates, or change of principal business;

•

a provision limiting oil and natural gas swaps to a volume not exceeding the percentages indicated in the following table:

The Months Immediately Following Any Date of Determination	Projected Production from Proved Developed Producing Reserves			Projected Production from Proved Reserves
1st through the 24th month		90	%		65	%
25th through the 36th month		85	%		50	%
37th and each succeeding month		85	%		0	%

•

a requirement that Holdings maintain a ratio of consolidated current assets (which includes availability under Holdings credit agreement) to consolidated current liabilities (which excludes current maturities of long-term debt, non-cash derivative assets and liabilities, and amounts due to Apollo under the Transaction Fee Agreement) of not less than 1.0 to 1.0;

•

a requirement that Holdings maintain a ratio of consolidated funded debt to consolidated Adjusted EBITDA (as defined in the Second Lien) of not more than 4.5 to 1.0; and

•

a requirement that Holdings maintain a ratio of the most recent present value of total proved reserves discounted at 10% to consolidated funded debt of not less than 1.5 to 1.0.

        As of December 31, 2012, Holdings was in compliance with all covenants of the Second Lien.

        The Second Lien contains customary events of default, which would permit the lenders to accelerate the debt if not cured within applicable grace periods. If an event of default occurs and is continuing, lenders with a majority of the aggregate commitments may require Wells Fargo Energy Capital, Inc. to declare all amounts outstanding under the Second Lien to be immediately due and payable.

F-47

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 6. Long-Term Debt (Continued)

Credit Agreements

Athlon SG Credit Agreement

        Athlon SG was a party to a credit agreement dated January 6, 2011 (as amended, the "SG Credit Agreement"), which was scheduled to mature on January 6, 2016. In May 2012, all outstanding borrowings under the SG Credit Agreement were repaid with borrowings under Holdings' new credit agreement discussed below and the SG Credit Agreement was terminated.

Athlon FE Credit Agreement

        Athlon FE was a party to a credit agreement dated October 3, 2011 (as amended, the "FE Credit Agreement"), which was scheduled to mature on October 3, 2016. In May 2012, all outstanding borrowings under the FE Credit Agreement were repaid with borrowings under Holdings' new credit agreement discussed below and the FE Credit Agreement was terminated.

Holdings Credit Agreement

        Holdings is a party to a credit agreement dated May 21, 2012 (as amended, the "Holdings Credit Agreement"), which matures on May 21, 2017. Upon entering into the Holdings Credit Agreement, all outstanding borrowings under each of the SG Credit Agreement and the FE Credit Agreement were repaid and the agreements were terminated. On September 5, 2012, Holdings amended the Holdings Credit Agreement to, among other things: (1) exclude amounts due to Apollo under the Transaction Fee Agreement from consolidated current liabilities in the calculation of consolidated current ratio; (2) provide for a reduction in the borrowing base of 20% of any amount incurred under the Second Lien in excess of $100 million; (3) waive the current ratio requirement for the quarter ended June 30, 2012; and (4) reaffirm the borrowing base at $245 million.

        The Holdings Credit Agreement provides for revolving credit loans to be made to Holdings from time to time and letters of credit to be issued from time to time for the account of Holdings or any of its restricted subsidiaries. The aggregate amount of the commitments of the lenders under the Holdings Credit Agreement is $700 million. Availability under the Holdings Credit Agreement is subject to a borrowing base, which is redetermined semi-annually and upon requested special redeterminations. On December 31, 2012, the borrowing base was $275 million and there were $237 million of outstanding borrowings, $38 million of borrowing capacity, and no outstanding letters of credit under the Holdings Credit Agreement.

        Holdings incurs a quarterly commitment fee at a rate of 0.5% per year on the unused portion of the Holdings Credit Agreement.

        Obligations under the Holdings Credit Agreement are secured by a first-priority security interest in substantially all of Holdings' proved reserves and in the equity interests of its operating subsidiaries. In addition, obligations under the Holdings Credit Agreement are guaranteed by Holdings' operating subsidiaries.

        Loans under the Holdings Credit Agreement are subject to varying rates of interest based on (1) outstanding borrowings in relation to the borrowing base and (2) whether the loan is a Eurodollar loan or a base rate loan. Eurodollar loans under the Holdings Credit Agreement bear interest at the Eurodollar rate plus the applicable margin indicated in the following table, and base rate loans under

F-48

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 6. Long-Term Debt (Continued)

the Holdings Credit Agreement bear interest at the base rate plus the applicable margin indicated in the following table:

Ratio of Outstanding Borrowings to Borrowing Base	Applicable Margin for Eurodollar Loans			Applicable Margin for Base Rate Loans
Less than .50 to 1		2.00	%		1.00	%
Greater than or equal to .50 to 1 but less than .75 to 1		2.25	%		1.25	%
Greater than or equal to .75 to 1 but less than .90 to 1		2.50	%		1.50	%
Greater than or equal to .90 to 1		2.75	%		1.75	%

        The "Eurodollar rate" for any interest period (either one, two, three, or six months, as selected by Holdings) is the rate equal to the LIBOR for deposits in dollars for a similar interest period. The "Base Rate" is calculated as the highest of: (1) the annual rate of interest announced by Bank of America, N.A. as its "prime rate"; (2) the federal funds effective rate plus 0.5%; or (3) except during a "LIBOR Unavailability Period," the Eurodollar rate (for dollar deposits for a one-month term) for such day plus 1.0%.

        Any outstanding letters of credit reduce the availability under the Holdings Credit Agreement. Borrowings under the Holdings Credit Agreement may be repaid from time to time without penalty.

        The Holdings Credit Agreement contains covenants including, among others, the following:

•

a prohibition against incurring debt, subject to permitted exceptions;

•

a restriction on creating liens on Holdings' assets and the assets of its operating subsidiaries, subject to permitted exceptions;

•

restrictions on merging and selling assets outside the ordinary course of business;

•

restrictions on use of proceeds, investments, transactions with affiliates, or change of principal business;

•

a provision limiting oil and natural gas swaps to a volume not exceeding the percentages indicated in the following table:

The Months Immediately Following Any Date of Determination	Projected Production from Proved Developed Producing Reserves			Projected Production from Proved Reserves
1st through the 24th month		90	%		65	%
25th through the 36th month		85	%		50	%
37th and each succeeding month		85	%		0	%

•

a requirement that Holdings maintain a ratio of consolidated current assets (which includes availability under the Holdings Credit Agreement) to consolidated current liabilities (which excludes current maturities of long-term debt, obligations to Apollo arising from the Transaction Fee Agreement, and non-cash derivative assets and liabilities) of not less than 1.0 to 1.0; and

•

a requirement that Holdings maintain a ratio of consolidated funded debt to consolidated Adjusted EBITDA (as defined in the Holdings Credit Agreement) of not more than 4.0 to 1.0.

F-49

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 6. Long-Term Debt (Continued)

        As of December 31, 2012, Holdings was in compliance with all covenants of the Holdings Credit Agreement.

        The Holdings Credit Agreement contains customary events of default, which would permit the lenders to accelerate the debt if not cured within applicable grace periods. If an event of default occurs and is continuing, lenders with a majority of the aggregate commitments may require Bank of America, N.A. to declare all amounts outstanding under the Holdings Credit Agreement to be immediately due and payable.

Long-Term Debt Maturities

        The following table shows Holdings' long-term debt maturities as of December 31, 2012:

	Payments Due by Period
	Total		2013		2014		2015		2016		2017		Thereafter
	(in thousands)
Holdings Credit Agreement	$	237,000	$	—	$	—	$	—	$	—	$	237,000	$	—
Second Lien		125,000		—		—		—		—		125,000		—
Total	$	362,000	$	—	$	—	$	—	$	—	$	362,000	$	—

        During 2012 and 2011, the weighted-average interest rate for total indebtedness was 4.3% and 3.8%, respectively.

Note 7. Partners' Equity

        On August 23, 2010, Athlon SG entered into a limited partnership agreement with its management group and Apollo. On July 22, 2011, the partnership agreement was amended and restated resulting in the formation of Holdings. The amended and restated partnership agreement required all of Athlon SG's equity contributions to be contributed to Holdings. The holders of all Class A and Class B limited partner units in Athlon SG contributed these units to Holdings in exchange for equivalent units of Holdings. Apollo and Holdings' management group are Class A limited partners in Athlon. The following table shows the partnership interest in Holdings as of December 31, 2012:

		Partnership Interest
Athlon Holdings LLC	General Partner		0.0	%
Apollo Athlon Holdings LLC	Class A Partner		97.2	%
Management group	Class A Partner		2.8	%

        As of December 31, 2012, Holdings had remaining capital commitments of approximately $38.1 million from Apollo and none from management.

Note 8. Employee Benefit Plans

401(k) Plan

        Holdings made contributions to its 401(k) plan, which is a voluntary and contributory plan for eligible employees based on a percentage of employee contributions, of approximately $454 thousand

F-50

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 8. Employee Benefit Plans (Continued)

and $219 thousand during 2012 and 2011, respectively. Holdings' 401(k) plan does not allow employees to invest in securities of Holdings.

Class B Limited Partner Interests

        Holdings' limited partnership agreement provides for the issuance of Class B limited partner interests. The Class B interests entitle the holder to participate in the net profits of Holdings, but are subject to various performance criteria. Class A interest holders are entitled to a return of their initial investment plus interest compounded at 8% annually (the "Class A Preference Amount"). Upon the occurrence of a liquidity event and after the Class A Preference Amount has been satisfied, 80% and 20% of the remaining net profits will be distributed to holders of Class A interests and Class B interests, respectively. The Class B interests vest over four or five years or upon certain performance thresholds being met by Holdings. Class B interests can also vest on the occurrence of certain events such as a change in control or in some cases upon termination of employment with Holdings. The total number of Class B interests that may be issued pursuant to the partnership agreement is 100,000. As of December 31, 2012, there were 6,200 Class B interests available for issuance under the partnership agreement. Class B interests that are forfeited will again become available for issuance under the partnership agreement.

        Management evaluated the terms of the Class B interests granted during 2010, in particular the potential impact of the performance criteria on the potential value of the Class B interests, and concluded that any compensation expense related to those grants would have been nominal. Management had independent valuations of its Class B interests granted during 2012 and 2011 and recorded approximately $152 thousand and $106 thousand, respectively, of non-cash equity-based compensation expense, which was allocated to LOE and general and administrative expenses in the accompanying Consolidated Statements of Operations based on the allocation of the respective employees' cash compensation. During 2012, Holdings also capitalized approximately $93 thousand of non-cash stock-based compensation expense as a component of "Proved properties, including wells and related equipment" in the accompanying Consolidated Balance Sheets.

        The fair value of Class B interests granted was estimated on the grant date using an option pricing model based on the following assumptions for the periods indicated:

	Year Ended December 31,
	2012			2011
Expected volatility		47	%		44	%
Expected dividend yield		0	%		0	%
Expected term (in years)		1.52			1.65
Risk-free interest rate		0.23	%		0.35	%
Weighted-average grant date fair value per interest	$	128.94		$	134.84

        The expected volatility was calculated based on the average historical volatility of each company in Holdings' peer group based on historical stock price data. The expected term of the Class B interests was based on expectations about future behavior. The risk-free interest rate was based on the U.S. Treasury yield curve in effect at the grant date for a period of time commensurate with the expected term of the Class B interests.

F-51

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 8. Employee Benefit Plans (Continued)

        The following table summarizes the changes in Holdings' Class B interests for the periods indicated:

	Year Ended December 31,
	2012					2011
	Number of Class B Interests			Weighted- Average Grant Date Fair Value		Number of Class B Interests			Weighted- Average Grant Date Fair Value
Outstanding at beginning of period		68,662		$	15.93		82,153		$	—
Granted		2,195			128.94		9,050			134.84
Vested		(20,375	)		11.32		(19,046	)		3.11
Forfeited		(270	)		140.72		(3,495	)		19.13
Outstanding at end of year		50,212			22.07		68,662			15.93

        The following table provides information regarding the expected vesting of Holdings' outstanding Class B interests at December 31, 2012:

	Year of Vesting
Year of Grant	2013		2014		2015		2016		2017		Total
2010		18,664		14,497		8,664		—		—		41,825
2011		1,711		1,711		1,711		1,329		—		6,462
2012		385		385		385		385		385		1,925
Total		20,760		16,593		10,760		1,714		385		50,212

        As of December 31, 2012, Holdings had approximately $1.0 million of total unrecognized compensation cost related to unvested Class B interests, which is expected to be recognized over a weighted-average period of approximately 3.7 years. During 2012 and 2011, there were 20,375 and 19,046, respectively, Class B interests that vested, the total fair value of which was approximately $231 thousand and $59 thousand, respectively.

Note 9. Fair Value Measurements

        The book values of cash and cash equivalents, accounts receivable, and accounts payable approximate fair value due to the short-term nature of these instruments. The book values of the Holdings Credit Agreement and the Second Lien approximate fair value as the interest rates are variable. Commodity derivative contracts are marked-to-market each quarter and are thus stated at fair value in the accompanying Consolidated Balance Sheets.

Commodity Derivative Contracts

        Commodity prices are often subject to significant volatility due to many factors that are beyond Holdings' control, including but not limited to: prevailing economic conditions, supply and demand of hydrocarbons in the marketplace, actions by speculators, and geopolitical events such as wars or natural disasters. Holdings' objective is to manage its exposure to oil price risk with swaps, puts, and collars. Swaps provide a fixed price for a notional amount of sales volumes. Puts provide a fixed floor price on

F-52

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 9. Fair Value Measurements (Continued)

a notional amount of sales volumes while allowing full price participation if the relevant index price closes above the floor price. Collars provide a floor price on a notional amount of sales volumes while allowing some additional price participation if the relevant index price closes above the floor price. This participation is limited by a ceiling price specified in the contract.

        The following table summarizes open commodity derivative contracts as of December 31, 2012:

Period	Average Daily Floor Volume		Weighted- Average Floor Price		Average Daily Cap Volume		Weighted- Average Cap Price		Average Daily Swap Volume		Weighted- Average Swap Price		Asset Fair Market Value
	(Bbl)		(per Bbl)		(Bbl)		(per Bbl)		(Bbl)		(per Bbl)		(in thousands)
2013		150	$	75.00		150	$	105.95		5,000	$	94.15	$	1,654
2014		—		—		—		—		4,950		92.65		956
2015		—		—		—		—		800		94.86		1,379
													$	3,989

        In January 2011, Holdings terminated certain oil puts that were in place at December 31, 2010 and received net proceeds of approximately $7.6 million, which is reflected as "Monetization of put options" in the "Investing activities" section of the accompanying Consolidated Statements of Cash Flows. In July and August 2011, Holdings entered into additional oil puts that included deferred premiums. These deferred premiums increased Holdings' interest expense by approximately $0.2 million during 2011. In October 2011, Holdings terminated the oil puts and entered into oil swaps that required the initial payment of premiums of approximately $2.0 million.

        Counterparty Risk.    At December 31, 2012, Holdings had committed 10% or greater (in terms of fair market value) of its oil derivative contracts in asset positions from the following counterparties:

Counterparty	Fair Market Value of Oil Derivative Contracts Committed
	(in thousands)
BNP Paribas	$	3,660
Royal Bank of Canada		711
Scotiabank		617

        Holdings does not require collateral from its counterparties for entering into financial instruments, so in order to mitigate the credit risk associated with financial instruments, Holdings enters into master netting agreements with certain counterparties. The master netting agreement is a standardized, bilateral contract between a given counterparty and Holdings. Instead of treating each financial transaction between the counterparty and Holdings separately, the master netting agreement enables the counterparty and Holdings to aggregate all financial trades and treat them as a single agreement. This arrangement is intended to benefit Holdings in two ways: (1) default by a counterparty under one financial trade can trigger rights to terminate all financial trades with such counterparty; and (2) netting of settlement amounts reduces Holdings' credit exposure to a given counterparty in the event of close-out. Holdings' accounting policy is to not offset fair value amounts between different counterparties for derivative instruments in the accompanying Consolidated Balance Sheets.

F-53

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 9. Fair Value Measurements (Continued)

Tabular Disclosures of Fair Value Measurements

        The following table summarizes the fair value of Holdings' derivative instruments as of the dates indicated (in thousands):

	Asset Derivatives					Liability Derivatives
		Fair Value					Fair Value
	Balance Sheet Location	December 31, 2012		December 31, 2011		Balance Sheet Location	December 31, 2012		December 31, 2011
Derivatives not designated as hedges
Commodity derivative contracts	Derivatives—current	$	2,246	$	—	Derivatives—current	$	592	$	5,908
Commodity derivative contracts	Derivatives—noncurrent		2,854		2,503	Derivatives—noncurrent		519		2,554
Total derivatives not designated as hedges		$	5,100	$	2,503		$	1,111	$	8,462

        The following table summarizes the effect of derivative instruments not designated as hedges on the accompanying Consolidated Statements of Operations for the periods indicated (in thousands):

		Amount of Loss (Gain) Recognized in Income
		Year ended December 31,
	Location of Loss (Gain) Recognized in Income
Derivatives Not Designated as Hedges		2012			2011
Commodity derivative contracts	Derivative fair value loss (gain)	$	(9,293	)	$	7,959

Fair Value Hierarchy

        Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. GAAP establishes a three-tier fair value hierarchy, which prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are defined as follows:

•

Level 1—Inputs such as unadjusted, quoted prices that are available in active markets for identical assets or liabilities.

•

Level 2—Inputs, other than quoted prices within Level 1, that are either directly or indirectly observable.

•

Level 3—Inputs that are unobservable for use when little or no market data exists requiring the use of valuation methodologies that result in management's best estimate of fair value.

        As required by GAAP, Holdings utilizes the most observable inputs available for the valuation technique used. The financial assets and liabilities are classified in their entirety based on the lowest

F-54

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 9. Fair Value Measurements (Continued)

level of input that is of significance to the fair value measurement. Holdings' assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of the financial assets and liabilities and their placement within the fair value hierarchy levels. The following methods and assumptions were used to estimate the fair values of Holdings' assets and liabilities that are accounted for at fair value on a recurring basis:

•

Level 2—Fair values of swaps were estimated using a combined income-based and market-based valuation methodology based upon forward commodity price curves obtained from independent pricing services. Holdings' collars and puts are average value options. Settlement is determined by the average underlying price over a predetermined period of time. Holdings uses observable inputs in an option pricing valuation model to determine fair value such as: (1) current market and contractual prices for the underlying instruments; (2) quoted forward prices for oil and natural gas; (3) interest rates, such as a LIBOR curve for a term similar to the commodity derivative contract; and (4) appropriate volatilities.

        Holdings adjusts the valuations from the valuation model for nonperformance risk. For commodity derivative contracts which are in an asset position, Holdings uses the counterparty's credit default swap rating. For commodity derivative contracts which are in a liability position, Holdings uses the average credit default swap rating of its peer companies as Holdings does not have its own credit default swap rating. All fair values have been adjusted for nonperformance risk resulting in an increase in the net commodity derivative asset of approximately $0.1 million as of December 31, 2012 and a decrease of the net commodity derivative liability of approximately $0.5 million as of December 31, 2011.

        The following table sets forth Holdings' assets and liabilities that were accounted for at fair value on a recurring basis as of the dates indicated:

				Fair Value Measurements at Reporting Date Using
Description	Asset (liability), net			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
	(in thousands)
As of December 31, 2012
Oil derivative contracts—swaps	$	4,069		$	—	$	4,069		$	—
Oil derivative contracts—collars and puts		(80	)		—		(80	)		—
Total	$	3,989		$	—	$	3,989		$	—
As of December 31, 2011
Oil derivative contracts—swaps	$	(5,392	)	$	—	$	(5,392	)	$	—
Oil derivative contracts—collars and puts		(567	)		—		—			(567	)
Total	$	(5,959	)	$	—	$	(5,392	)	$	(567	)

        Holdings' oil collars were classified as Level 3 in the fair value hierarchy as of December 31, 2011. Beginning in 2012, these contracts were classified as Level 2 in the fair value hierarchy as a result of

F-55

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 9. Fair Value Measurements (Continued)

Holdings' ability to obtain appropriate volatilities. The following table summarizes the changes in the fair value of Holdings' Level 3 assets and liabilities that were previously classified as Level 3 for the periods indicated:

	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Oil Derivative Contracts— Collars and Puts
	(in thousands)
Balance at January 1, 2011	$	7,475
Total gains (losses):
Included in earnings		(461	)
Monetization of put options		(7,625	)
Purchases (premiums paid)		44
Balance at December 31, 2011		(567	)
Transfers out of Level 3		567
Balance at December 31, 2012	$	—

        Since Holdings does not use hedge accounting for its commodity derivative contracts, all gains and losses on its Level 3 assets and liabilities are included in "Derivative fair value loss (gain)" in the accompanying Consolidated Statements of Operations.

Note 10. Related Party Transactions

Transaction Fee Agreement

        Holdings is a party to a Transaction Fee Agreement, dated August 23, 2010, which requires Holdings to pay a fee to Apollo equal to 2% of the total equity contributed to Holdings, as defined in the agreement, in exchange for consulting and advisory services provided by Apollo. In October 2012, Apollo assigned its rights and obligations under the Transaction Fee Agreement to Apollo Global Securities, LLC. In December 2012, Holdings incurred a transaction fee payable to Apollo Global Securities, LLC of $0.8 million related to a $40 million capital contribution received from Apollo. Upon the closing of the SandRidge acquisition in January 2011, Athlon SG incurred a transaction fee payable to Apollo of approximately $2.3 million. Upon the closing of the Element acquisition in October 2011, Athlon FE incurred a transaction fee payable to Apollo of approximately $4.3 million. All transaction fees incurred under the Transaction Fee Agreement are included in "Acquisition costs" in the accompanying Consolidated Statements of Operations during the period incurred.

Services Agreement

        Holdings is also a party to a Services Agreement, dated August 23, 2010, which requires Holdings to further compensate Apollo for consulting and advisory services equal to a minimum of $62,500 per quarter or 1% of net income before interest, income taxes, and DD&A, not to exceed $500,000 in any calendar year. The Services Agreement also provides for reimbursement to Apollo for any reasonable out-of-pocket expenses incurred while performing under the Services Agreement. During 2012 and

F-56

ATHLON HOLDINGS LP

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

Note 10. Related Party Transactions (Continued)

2011, Holdings incurred approximately $493 thousand and $411 thousand, respectively, of fees under the Services Agreement, which is included in "General and administrative expenses" in the accompanying Consolidated Statements of Operations.

Note 11. Subsequent Events

        In January 2013, Holdings increased the borrowing base under the Holdings Credit Agreement to $295 million.

        During February 2013, Holdings entered into additional oil swaps. The following table summarizes open commodity derivative contracts as of March 8, 2013:

Period	Average Daily Floor Volume		Weighted- Average Floor Price		Average Daily Cap Volume		Weighted- Average Cap Price		Average Daily Swap Volume		Weighted- Average Swap Price
	(Bbl)		(per Bbl)		(Bbl)		(per Bbl)		(Bbl)		(per Bbl)
2013		150	$	75.00		150	$	105.95		5,500	$	94.50
2014		—		—		—		—		5,450		92.83
2015		—		—		—		—		1,300		93.18

        In February 2013, Holdings also entered into basis differential swaps for 5,000 Bbls/D at $1.20/Bbl for March through December 2013.

        These financial statements considered subsequent events through March 8, 2013, the date the consolidated financial statements were available to be issued.

F-57

ATHLON HOLDINGS LP

SUPPLEMENTARY INFORMATION

Capitalized Costs and Costs Incurred Relating to Oil and Natural Gas Producing Activities

        The capitalized cost of oil and natural gas properties was as follows as of the dates indicated:

	December 31,
	2012			2011
	(in thousands)
Properties and equipment, at cost—full cost method:
Proved properties, including wells and related equipment	$	788,571		$	399,205
Unproved properties		89,860			125,036
Accumulated depletion, depreciation, and amortization		(73,824	)		(19,589	)
	$	804,607		$	504,652

        The following table summarizes costs incurred related to oil and natural gas properties for the periods indicated:

	Year ended December 31,
	2012		2011
	(in thousands)
Acquisitions:
Proved propertiesa	$	42,122	$	287,400
Unproved propertiesb		38,908		130,273
Total acquisitions		81,030		417,673
Development:
Drilling and exploitationc		201,174		71,403
Total development		201,174		71,403
Exploration:
Drilling and exploitationd		75,008		17,829
Total exploration		75,008		17,829
Total costs incurred	$	357,212	$	506,905

^a

Includes asset retirement obligations incurred of approximately $60 thousand and $3.3 million during 2012 and 2011, respectively.

^b

Costs incurred for unproved properties are excluded from the amortization base.

^c

Includes asset retirement obligations incurred of approximately $606 thousand and $108 thousand during 2012 and 2011, respectively.

^d

Includes asset retirement obligations incurred of approximately $209 thousand and $58 thousand during 2012 and 2011, respectively.

Oil & Natural Gas Producing Activities—Unaudited

        All of Holdings' results of operations relate to oil and natural gas producing activities. Holdings only has one cost center, which is the Permian Basin in West Texas. Holdings average depletion rate per BOE of production was $21.03 and $20.32 for 2012 and 2011, respectively.

F-58

ATHLON HOLDINGS LP

SUPPLEMENTARY INFORMATION (Continued)

        The estimates of Holdings' proved reserves, which are located entirely within the United States, were prepared in accordance with rules and regulations established by the FASB. Proved oil and natural gas reserve quantities are based on internal estimates reviewed by independent petroleum engineers.

        Future prices received for production and future production costs may vary, perhaps significantly, from the prices and costs assumed for purposes of these estimates. There can be no assurance that the proved reserves will be developed within the periods assumed or that prices and costs will remain constant. Actual production may not equal the estimated amounts used in the preparation of reserve projections. Estimates of future net cash flows from Holdings' properties, and the representative value thereof, were made using 12-month first-day-of-the-month oil and natural gas average prices, as adjusted for basis or location differentials, held constant over the life of the reserves. Prices used in estimating Holdings' future net cash flows were as follows as of the dates indicated:

	December 31,
	2012		2011
Oil (per Bbl)	$	94.71	$	93.25
Natural gas (per Mcf)		2.75		3.53

        Net future cash inflows have not been adjusted for commodity derivative contracts outstanding at the end of the year. Future cash inflows are reduced by estimated production and development costs, which are based on year-end economic conditions and held constant throughout the life of the properties, and the estimated effect of future income taxes due to the Texas margin tax. Future federal income taxes have not been deducted from future net revenues in the calculation of Holdings' standardized measure as each partner is separately taxed on his share of Holdings' taxable income.

        There are numerous uncertainties inherent in estimating quantities of proved reserves and in projecting future rates of production and timing of development expenditures. Oil and natural gas reserve engineering is and must be recognized as a subjective process of estimating underground accumulations of oil and natural gas that cannot be measured in any exact way, and estimates of other engineers might differ materially from those included herein. The accuracy of any reserve estimate is a function of the quality of available data and engineering, and estimates may justify revisions based on the results of drilling, testing, and production activities. Accordingly, reserve estimates are often materially different from the quantities of oil and natural gas that are ultimately recovered. Reserve estimates are integral to management's analysis of impairment of oil and natural gas properties and the calculation of DD&A on these properties.

F-59

ATHLON HOLDINGS LP

SUPPLEMENTARY INFORMATION (Continued)

        Holdings' estimated net quantities of proved reserves were as follows as of the dates indicated:

	December 31,
	2012		2011
Proved developed reserves:
Oil (MBbls)		14,470		7,942
Natural gas (MMcf)		31,965		14,063
Natural gas liquids (MBbls)		5,900		3,211
Combined (MBOE)		25,698		13,496
Proved undeveloped reserves:
Oil (MBbls)		34,953		18,030
Natural gas (MMcf)		71,718		37,497
Natural gas liquids (MBbls)		13,375		8,338
Combined (MBOE)		60,281		32,618
Proved reserves:
Oil (MBbls)		49,423		25,972
Natural gas (MMcf)		103,683		51,560
Natural gas liquids (MBbls)		19,275		11,549
Combined (MBOE)		85,979		46,114

        The changes in Holdings' proved reserves were as follows for the periods indicated:

	Oil (MBbls)			Natural Gas (MMcf)			Natural Gas Liquids (MBbls)			Oil Equivalent (MBOE)
Balance at December 31, 2010		—			—			—			—
Purchases of minerals-in-place		21,308			39,179			8,935			36,773
Extensions and discoveries		4,200			10,064			2,285			8,162
Revisions of previous estimates		1,020			3,334			568			2,143
Production		(556	)		(1,017	)		(239	)		(964	)
Balance, December 31, 2011		25,972			51,560			11,549			46,114
Purchases of minerals-in-place		5,203			5,874			1,162			7,344
Extensions and discoveries		23,471			56,736			10,525			43,452
Revisions of previous estimates1		(3,766	)		(7,324	)		(3,366	)		(8,352	)
Production		(1,457	)		(3,163	)		(595	)		(2,579	)
Balance, December 31, 2012		49,423			103,683			19,275			85,979

¹

During 2012, Holdings experienced negative revisions of previous estimates, 7,185 MBOE of which was related to proved undeveloped locations that are not currently scheduled to be drilled within the next five years.

        The following is a standardized measure of the discounted net future cash flows and changes applicable to proved reserves. The future cash flows are discounted at 10% per year and assume continuation of existing economic conditions.

        The standardized measure of discounted future net cash flows, in management's opinion, should be examined with caution. The basis for this table is the reserve studies prepared by independent petroleum engineering consultants, which contain imprecise estimates of quantities and rates of

F-60

ATHLON HOLDINGS LP

SUPPLEMENTARY INFORMATION (Continued)

production of reserves. Revisions of previous year estimates can have a significant impact on these results. Also, exploration costs in one year may lead to significant discoveries in later years and may significantly change previous estimates of proved reserves and their valuation. Therefore, the standardized measure of discounted future net cash flow is not necessarily indicative of the fair value of Holdings' proved oil and natural gas properties.

        The data presented should not be viewed as representing the expected cash flow from or current value of, existing proved reserves since the computations are based on a large number of estimates and arbitrary assumptions. Reserve quantities cannot be measured with precision and their estimation requires many judgmental determinations and frequent revisions. Actual future prices and costs are likely to be substantially different from the prices and costs utilized in the computation of reported amounts.

        Holdings' standardized measure of discounted estimated future net cash flows was as follows as of the dates indicated:

	December 31,
	2012			2011
	(in thousands)
Future cash inflows	$	5,361,058		$	3,155,756
Future production costs		(1,811,514	)		(972,343	)
Future development costs		(1,060,785	)		(569,672	)
Future income taxes		(37,527	)		(22,090	)
Future net cash flows		2,451,232			1,591,651
10% annual discount		(1,600,318	)		(1,010,494	)
Standardized measure of discounted estimated future net cash flows	$	850,914		$	581,157

F-61

ATHLON HOLDINGS LP

SUPPLEMENTARY INFORMATION (Continued)

        The changes in Holdings' standardized measure of discounted estimated future net cash flows were as follows for the periods indicated:

	Year ended December 31,
	2012			2011
	(in thousands)
Net change in prices and production costs	$	(109,214	)	$	73,093
Purchases of minerals-in-place		81,304			394,248
Extensions, discoveries, and improved recovery		376,493			101,396
Revisions of previous quantity estimates		(189,505	)		27,499
Production, net of production costs		(121,170	)		(47,626	)
Previously estimated development costs incurred during the period		119,361			43,994
Accretion of discount		59,144			20,072
Change in estimated future development costs		60,210			(22,239	)
Net change in income taxes		(5,378	)		(2,809	)
Change in timing and other		(1,488	)		(6,471	)
Net change in standardized measure		269,757			581,157
Standardized measure, beginning of year		581,157			—
Standardized measure, end of year	$	850,914		$	581,157

F-62

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Supervisors and Partners
Athlon Holdings LP

        We have audited the accompanying carve out balance sheet of Element Petroleum, LP's ("Element") Permian Basin Operations as defined in Note 1 as of September 30, 2011, and the related carve out statements of operations, owner's net equity, and cash flows for the nine months then ended. These financial statements are the responsibility of Athlon Holdings LP's management. Our responsibility is to express an opinion on these financial statements based on our audit.

        We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the financial statements are free of material misstatement. We were not engaged to perform an audit of Element's internal control over financial reporting. Our audit included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of Element's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion.

        In our opinion, the financial statements referred to above present fairly, in all material respects, the carve out financial position of Element's Permian Basin Operations included in the Purchase and Sale Agreement with Athlon FE Operating LLC at September 30, 2011 and the carve out results of its operations and its cash flows for the nine months then ended in conformity with U.S. generally accepted accounting principles.

/s/ UHY LLP

Houston, Texas
May 16, 2012

F-63

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

CARVE OUT BALANCE SHEET

(in thousands)

	September 30, 2011
ASSETS
Current assets:
Accounts receivable	$	2,253
Inventory		271
Total current assets		2,524
Properties and equipment, at cost—successful efforts method:
Proved properties, including wells and related equipment		121,568
Unproved properties		13,515
Accumulated depletion, depreciation, and amortization		(30,732	)
		104,351
Other property and equipment		939
Accumulated depreciation		(173	)
		766
Other		73
Total assets	$	107,714
LIABILITIES AND OWNER'S NET EQUITY
Current liabilities:
Accounts payable	$	6,501
Accrued liabilities:
Lease operating		170
Production, severance, and ad valorem taxes		401
Development capital		2,516
Revenues payable		1,802
Other		305
Total current liabilities		11,695
Asset retirement obligations		1,754
Total liabilities		13,449
Commitments and contingencies (see Note 3)
Owner's net equity		94,265
Total liabilities and owner's net equity	$	107,714

The accompanying notes are an integral part of these carve out financial statements.

F-64

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

CARVE OUT STATEMENT OF OPERATIONS

(in thousands)

	Nine Months Ended September 30, 2011
Revenues:
Oil	$	17,406
Natural gas		6,109
Management fees		422
Total revenues		23,937
Expenses:
Production:
Lease operating		1,962
Production, severance, and ad valorem taxes		1,590
Depletion, depreciation, and amortization		5,594
General and administrative		1,897
Accretion		62
Total expenses		11,105
Operating income		12,832
Interest, net		1
Net income	$	12,833

The accompanying notes are an integral part of these carve out financial statements.

F-65

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

CARVE OUT STATEMENT OF CHANGES IN OWNER'S NET EQUITY

(in thousands)

Balance at December 31, 2010	$	45,041
Net contributions from owner		36,391
Net income		12,833
Balance at September 30, 2011	$	94,265

The accompanying notes are an integral part of these carve out financial statements.

F-66

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

CARVE OUT STATEMENT OF CASH FLOWS

(in thousands)

	Nine Months Ended September 30, 2011
Cash flows from operating activities:
Net income	$	12,833
Adjustments to reconcile net income to net cash provided by operating activities:
Depletion, depreciation, and amortization		5,594
Accretion		62
Changes in operating assets and liabilities:
Accounts receivable		(1,563	)
Inventory		89
Accounts payable		(1,118	)
Other current liabilities		3,470
Net cash provided by operating activities		19,367
Cash flows from investing activities:
Acquisition of oil and natural gas properties		(2,085	)
Development of oil and natural gas properties		(53,640	)
Other		(33	)
Net cash used in investing activities		(55,758	)
Cash flows from financing activities:
Net contributions from owner		36,391
Net cash provided by financing activities		36,391
Increase (decrease) in cash and cash equivalents		—
Cash and cash equivalents, beginning of period		—
Cash and cash equivalents, end of period	$	—
Non-cash investing activities:
Establishment of asset retirement obligations	$	639

The accompanying notes are an integral part of these carve out financial statements.

F-67

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

NOTES TO CARVE OUT FINANCIAL STATEMENTS

Note 1. Description of Business and Basis of Presentation

        Athlon FE Energy LP together with its subsidiary, ("Athlon FE"), a Delaware limited partnership, was formed on July 22, 2011 (the "date of inception"), and is the holding company for Athlon FE Operating LLC (the "Company"), which was also formed on July 22, 2011. Athlon FE seeks to execute a low-risk "acquire and exploit" strategy by establishing a footprint in proven oil and natural gas basins with initial acquisitions of mature producing properties that have long-lived, predictable reserves in the onshore continental United States. On October 3, 2011, the Company acquired certain oil and natural gas properties from Element Petroleum, LP ("Element") in the Permian Basin of West Texas (the "Permian Basin Operations") for approximately $253.2 million.

        The accompanying carve out financial statements and related notes thereto represent the financial position, results of operations, changes in owner's net equity, and cash flows of the Permian Basin Operations. The carve out financial statements have been prepared in accordance with Regulation S-X, Article 3, "General instructions as to financial statements" and Staff Accounting Bulletin ("SAB") Topic 1-B, "Allocations of Expenses and Related Disclosure in Financial Statements of Subsidiaries, Divisions or Lesser Business Components of Another Entity". Certain expenses incurred by Element are only indirectly attributable to its ownership of the Permian Basin Operations as Element owns interests in numerous other oil and natural gas properties. As a result, certain assumptions and estimates were made in order to allocate a reasonable share of such expenses to the Permian Basin Operations so that the accompanying carve out financial statements reflect substantially all the costs of doing business borne by Element on behalf of the Permian Basin Operations. These allocations may not be indicative of the cost of future operations or the amount of future allocations. The allocations and related estimates and assumptions are described more fully in "Note 2. Summary of Significant Accounting Policies" and "Note 5. Related Party Transactions".

Note 2. Summary of Significant Accounting Policies

        The accompanying carve out financial statements were derived from the accounting records of Element.

Allocation of Costs

        The accompanying carve out financial statements have been prepared in accordance with SAB Topic 1-B. These rules require allocations of costs for salaries and benefits, depreciation, rent, accounting, legal services, and other expenses. Element has allocated general and administrative expenses to the Permian Basin Operations using an average of its proportionate share of Element's consolidated oil and natural gas revenues, capital expenditures, and well count. Management believes the allocation methodologies used are reasonable and result in an allocation of the cost of doing business borne by Element on behalf of the Permian Basin Operations. These allocations may not be indicative of the cost of future operations or the amount of future allocations.

Use of Estimates

        Preparing carve out financial statements in conformity with accounting principles generally accepted in the United States ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, and expenses, and the disclosure of contingent assets and liabilities in the carve out financial statements. Also, certain amounts in the accompanying carve out financial statements have been allocated in a way that management believes is

F-68

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

NOTES TO CARVE OUT FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

reasonable and consistent in order to depict the historical financial position, results of operations, and cash flows of the Permian Basin Operations on a stand-alone basis. Although management believes these estimates are reasonable, actual results could differ from these estimates.

        Estimates made in preparing these carve out financial statements include, among other things, estimates of the proved oil and natural gas reserve volumes used in calculating depletion, depreciation, and amortization ("DD&A") expense; the estimated future cash flows and fair value of properties used in determining the need for any impairment write-down; operating costs accrued; volumes and prices for revenues accrued; and the timing and amount of future abandonment costs used in calculating asset retirement obligations. Changes in the assumptions used could have a significant impact on results in future periods.

Cash and Cash Equivalents

        Element provided cash as needed to support the Permian Basin Operations and collected cash from sales of production. Consequently, the accompanying Carve Out Balance Sheet do not include any cash balances. Net cash paid from Element to the Permian Basin Operations is reflected as net contributions from owner on the accompanying Carve Out Statement of Owner's Net Equity and Carve Out Statement of Cash Flows.

Accounts Receivable

        Trade accounts receivable, which are primarily from oil and natural gas sales, are recorded at the invoiced amount and do not bear interest. Element routinely reviews outstanding accounts receivable balances, assesses the financial strength of its customers, and records a reserve for amounts not expected to be fully recovered. Actual balances are not applied against the reserve until substantially all collection efforts have been exhausted. At September 30, 2011, the Permian Basin Operations had no allowance for doubtful accounts.

Properties and Equipment

        Oil and Natural Gas Properties.    The Permian Basin Operations use the successful efforts method of accounting for its oil and natural gas properties under the provisions of the "Financial Accounting and Reporting by Oil and Gas Producing Companies" topic of the Financial Accounting Standards Board's (the "FASB") Accounting Standards Codification (the "ASC"). Under this method, all costs associated with productive and nonproductive development wells are capitalized. Exploration expenses, including geological and geophysical expenses and delay rentals, are charged to expense as incurred. Costs associated with drilling exploratory wells are initially capitalized pending determination of whether the well is economically productive or nonproductive.

        If an exploratory well does not find reserves or does not find reserves in a sufficient quantity as to make them economically producible, the previously capitalized costs would be expensed in the accompanying Carve Out Statement of Operations and shown as an adjustment to net income in the "Operating activities" section of the accompanying Carve Out Statement of Cash Flows in the period in which the determination was made. If an exploratory well finds reserves but they cannot be classified as proved, the associated cost continues to be capitalized as long as the well has found a sufficient quantity of reserves to justify its completion as a producing well and sufficient progress is being made in assessing the reserves and the operating viability of the project. If subsequently it is determined that

F-69

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

NOTES TO CARVE OUT FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

these conditions do not continue to exist, all previously capitalized costs associated with the exploratory well would be expensed and shown as an adjustment to net income in the "Operating activities" section of the accompanying Carve Out Statement of Cash Flows in the period in which the determination was made. Re-drilling or directional drilling in a previously abandoned well is classified as development or exploratory based on whether it is in a proved or unproved reservoir. Costs for repairs and maintenance to sustain or increase production from the existing producing reservoir are charged to expense as incurred. Costs to recomplete a well in a different unproved reservoir are capitalized pending determination that economic reserves have been added. If the recompletion is unsuccessful, the costs would be charged to expense. All capitalized costs associated with both development and exploratory wells are shown as "Development of oil and natural gas properties" in the "Investing activities" section of the accompanying Carve Out Statement of Cash Flows.

        Significant tangible equipment added or replaced that extends the useful or productive life of the property is capitalized. Costs to construct facilities or increase the productive capacity from existing reservoirs are capitalized. Capitalized costs are amortized on a unit-of-production basis over the remaining life of proved developed reserves or total proved reserves, as applicable. Natural gas volumes are converted to barrels of oil equivalent ("BOE") at the rate of six thousand cubic feet ("Mcf") of natural gas to one barrel ("Bbl") of oil. This convention is not an equivalent price basis and there may be a large difference in value between an equivalent volume of oil versus an equivalent volume of natural gas.

        DD&A of capitalized costs for producing oil and natural gas properties is provided for using the unit-of-production method based on estimates of proved oil and natural gas reserves on a field-by-field basis. Costs of significant nonproducing properties, wells in progress of being drilled, and development projects are excluded from depletion until such time as the related project is developed and proved reserves are established or impairment is determined. The costs of retired, sold, or abandoned properties that constitute part of an amortization base are charged or credited, net of proceeds received, to accumulated DD&A.

        Reserve engineers estimate the reserves of the Permian Basin Operations annually on December 31.

        In accordance with the provisions of the "Accounting for the Impairment or Disposal of Long-Lived Assets" topic of the ASC, management assesses the need for an impairment of long-lived assets to be held and used, including proved oil and natural gas properties, whenever events and circumstances indicate that the carrying value of the asset may not be recoverable. If impairment is indicated based on a comparison of the asset's carrying value to its undiscounted expected future net cash flows, then an impairment charge is recognized to the extent the asset's carrying value exceeds its fair value. Expected future net cash flows are based on existing proved reserves, forecasted production information, and management's outlook of future commodity prices. Any impairment charge incurred is expensed and reduces the net basis in the asset. Management aggregates proved property for impairment testing the same way as for calculating DD&A. The price assumptions used to calculate undiscounted cash flows is based on judgment. Management uses prices consistent with the prices it believes a market participant would use in bidding on acquisitions and/or assessing capital projects. These price assumptions are critical to the impairment analysis as lower prices could trigger impairment.

F-70

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

NOTES TO CARVE OUT FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

        Unproved properties, the majority of which relate to the acquisition of leasehold interests, are assessed for impairment on a property-by-property basis for individually significant balances and on an aggregate basis for individually insignificant balances. If the assessment indicates impairment, a loss is recognized by providing a valuation allowance at the level at which impairment was assessed. The impairment assessment is affected by economic factors such as the results of exploration activities, commodity price outlooks, remaining lease terms, and potential shifts in business strategy employed by management. In the case of individually insignificant balances, the amount of the impairment loss recognized is determined by amortizing the portion of these properties' costs which management believes will not be transferred to proved properties over the remaining life of the lease.

        Amounts shown in the accompanying Carve Out Balance Sheet as "Proved properties, including wells and related equipment" consisted of the following as of the date indicated:

	September 30, 2011
	(in thousands)
Proved leasehold costs	$	15,342
Wells and related equipment—Completed		97,029
Wells and related equipment—In process		9,197
Total proved properties	$	121,568

        Other Property and Equipment.    Other property and equipment is carried at cost. Depreciation is expensed on a straight-line basis over estimated useful lives, which range from three to seven years. Gains or losses from the disposal of other property and equipment are recognized in the period realized.

Asset Retirement Obligations

        Management applies the provisions of the "Accounting for Asset Retirement Obligation" topic of the ASC. The Permian Basin Operations have significant obligations under its lease agreements and federal regulation to remove its equipment and restore land at the end of oil and natural gas production operations. These asset retirement obligations are primarily associated with plugging and abandoning wells and land remediation. Estimating the future restoration and removal cost is difficult and requires management to make estimates and judgments because most of the removal obligations are many years in the future and contracts and regulation often have vague descriptions of what constitutes removal. Asset removal technologies and costs are constantly changing, as are regulatory, political, environmental, safety, and public relations considerations. At the time the well is drilled, the Permian Basin Operations record a separate liability for the estimated fair value of its asset retirement obligations, with an offsetting increase to the related oil and natural gas properties representing asset retirement costs in the accompanying Carve Out Balance Sheet. The cost of the related oil and natural gas asset, including the asset retirement cost, is included in the Permian Basin Operations' capitalized property costs. The estimated fair value of an asset retirement obligation is the present value of the expected future cash outflows required to satisfy the asset retirement obligations discounted at Element's credit-adjusted, risk-free interest rate. Accretion expense is recognized over time as the discounted liability is accreted to its expected settlement value.

F-71

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

NOTES TO CARVE OUT FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

        Inherent to the present-value calculation are numerous estimates, assumptions, and judgments, including, but not limited to: the ultimate settlement amounts, inflation factors, credit-adjusted, risk-free rates, timing of settlement, and changes in the legal, regulatory, environmental, and political environments. To the extent future revisions to these assumptions affect the present value of the abandonment liability, management makes corresponding adjustments to both the asset retirement obligation and the related oil and natural gas property asset balance. Increases in the discounted asset retirement obligations resulting from the passage of time are reflected as additional accretion expense in the accompanying Carve Out Statement of Operations. Please read "Note 4. Asset Retirement Obligations" for additional information.

Owner's Net Equity

        The change in net assets that is not attributable to current period earnings is reflected as net contributions from owner for that period. As the Permian Basin Operations were not a separate legal entity during the period covered by these carve out financial statements, none of Element's debt is directly attributable to its ownership of the Permian Basin Operations, and no formal intercompany financing arrangement exists related to the Permian Basin Operations. Additionally, as debt cannot be specifically ascribed to the Permian Basin Operations, the accompanying Carve Out Statement of Operations do not include any allocation of interest expense incurred by Element related to the Permian Basin Operations.

Segment Reporting

        The Permian Basin Operations operate in only one industry: the oil and natural gas exploration and production industry in the United States. All revenues are derived from customers located in the United States.

Major Customers / Concentration of Credit Risk

        The following purchasers accounted for 10% or greater of the sales of production for the period indicated and the corresponding outstanding accounts receivable balance as of the date indicated:

	Percentage of Total Sales of Production for the			Outstanding Accounts Receivable Balance
Purchaser	Nine Months Ended September 30, 2011			As of September 30, 2011
				(in thousands)
Pecos Gathering		58	%	$	(10	)
DCP Midstream		15	%		424
LPC Crude Oil		16	%		747

Oil and Natural Gas Revenue Recognition

        Oil and natural gas revenues are recognized as oil and natural gas is produced and sold, net of royalties. Royalties are incurred based upon the actual price received from the sales. To the extent actual volumes and prices of oil and natural gas are unavailable for a given reporting period because of timing or information not received from third parties, the expected sales volumes and prices for those

F-72

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

NOTES TO CARVE OUT FINANCIAL STATEMENTS (Continued)

Note 2. Summary of Significant Accounting Policies (Continued)

properties are estimated and recorded as "Accounts receivable" in the accompanying Carve Out Balance Sheet. Natural gas revenues are recorded using the sales method of accounting whereby revenue is recognized based on actual sales of natural gas rather than the Permian Basin Operations' proportionate share of natural gas production. If the Permian Basin Operations' overproduced imbalance position (i.e., the Permian Basin Operations have cumulatively been over-allocated production) is greater than its share of remaining reserves, a liability would be recorded for the excess at period-end prices unless a different price is specified in the contract in which case that price is used. At September 30, 2011, the Permian Basin Operations had no oil inventories in pipelines or tanks and it had no natural gas imbalances. Revenue is not recognized for oil production in tanks.

Earnings Per Share

        During the period presented, the Permian Basin Operations were wholly owned by Element. Accordingly, earnings per share is not presented.

Fair Value of Financial Instruments

        Financial instruments in the accompanying Carve Out Balance Sheet include accounts receivable and accounts payable. The book values of accounts receivable and accounts payable approximate fair value due to the short-term nature of these instruments.

New Accounting Pronouncements

        In May 2011, the FASB issued Accounting Standards Update ("ASU") 2011-04, "Amendments to Achieve Common Fair Value Measurements and Disclosure Requirements in U.S. GAAP and IFRSs". ASU 2011-04 amended ASC 820 to converge the fair value measurement guidance in GAAP and International Financial Reporting Standards. Certain of the amendments clarify the application of existing fair value measurement requirements, while other amendments change a particular principle in ASC 820. In addition, ASU 2011-04 requires additional fair value disclosures. The amendments will be applied prospectively and are effective for annual periods beginning after December 15, 2011. Management does not believe the adoption of this guidance will have a material impact on the Permian Basin Operations' financial position, results of operations, or liquidity.

        In December 2011, the FASB issued ASU 2011-11, "Disclosures about offsetting Assets and Liabilities" requiring additional disclosure about offsetting and related arrangements. ASU 2011-11 is effective retrospectively for annual reporting periods beginning on or after January 1, 2013. The adoption of ASU 2011-11 will not impact the Permian Basin Operations' position, results of operations, or liquidity.

        No other new accounting pronouncements issued or effective during 2011 had or are expected to have a material impact on the Permian Basin Operations' carve out financial statements.

Note 3. Commitments and Contingencies

        The Permian Basin Operations are subject to various possible contingencies. Such contingencies include environmental issues and other matters. Although management believes it has complied with the various laws and regulations, administrative rulings and interpretations thereof, adjustments could be required as new interpretations and regulations are issued. In addition, production rates and

F-73

ELEMENT PETROLEUM, LP PERMIAN BASIN OPERATIONS

NOTES TO CARVE OUT FINANCIAL STATEMENTS (Continued)

Note 3. Commitments and Contingencies (Continued)

environmental matters are subject to regulation by various federal and state agencies. Additionally, the Permian Basin Operations have contractual obligations related to future plugging and abandonment expenses on oil and natural gas properties as discussed in "Note 4. Asset Retirement Obligations".

Note 4. Asset Retirement Obligations

        Asset retirement obligations relate to future plugging and abandonment expenses on oil and natural gas properties and related facilities disposal. The following table summarizes the changes in the Permian Basin Operations' asset retirement obligations for the period indicated:

	Nine Months Ended September 30, 2011
	(in thousands)
Balance at beginning of period	$	1,053
Acquisition of properties		—
Wells drilled		638
Accretion of discount		62
Revisions of previous estimates		1
Balance at end of period	$	1,754

Note 5. Related Party Transactions

        The employees supporting the operations of the Permian Basin Operations are employees of Element's management company. Accordingly, Element recognizes all employee-related expenses and liabilities in its consolidated financial statements. In addition to employee payroll-related expenses, Element incurred general and administrative expenses related to leasing office space and other corporate overhead expenses during the period covered by these carve out financial statements. For purposes of deriving the accompanying carve out financial statements, Element allocated general and administrative expenses to the Permian Basin Operations using an average of its proportionate share of Element's consolidated oil and natural gas revenues, capital expenditures, and well count. For the nine months ended September 30, 2011, the portion of Element's consolidated general and administrative expenses allocated to the Permian Basin Operations was 60.4%, or approximately $1.9 million.

Note 6. Subsequent Events

        These carve out financial statements considered subsequent events through May 16, 2012, the date the financial statements were available to be issued. No subsequent events requiring recognition or disclosure have occurred.

F-74

              Shares

Athlon Energy Inc.

Common Stock

PROSPECTUS

                        , 2013

Citigroup

        Until                        , 2013 (25 days after the date of this prospectus), all dealers that buy, sell or trade our common stock, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to the dealers' obligation to deliver a prospectus when acting as underwriters and with respect to their unsold allotments or subscriptions.

Part II

INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13.    Other Expenses of Issuance and Distribution

        The following table sets forth an itemized statement of the amounts of all expenses (excluding underwriting discounts and commissions) payable by us in connection with the registration of the common stock offered hereby. With the exception of the SEC registration fee, FINRA filing fee and NYSE listing fee), the amounts set forth below are estimates.

SEC registration fee	$	47,058
FINRA filing fee		52,250
NYSE listing fee		175,000
Accounting fees and expenses		500,000
Legal fees and expenses		2,000,000
Printing and engraving expenses		400,000
Transfer agent and registrar fees		5,000
Miscellaneous		1,820,692
Total	$	5,000,000

ITEM 14.    Indemnification of Directors and Officers

        Section 145 of the Delaware General Corporation Law permits a Delaware corporation to indemnify its officers, directors and other corporate agents to the extent and under the circumstances set forth therein. Our amended and restated certificate of incorporation and bylaws provide that we will indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding whether civil, criminal, administrative or investigative, by reason of the fact that he is or was our director or officer, or is or was serving at our request as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, in accordance with provisions corresponding to Section 145 of the Delaware General Corporation Law. These indemnification provisions may be sufficiently broad to permit indemnification of the registrant's executive officers and directors for liabilities, including reimbursement of expenses incurred, arising under the Securities Act.

        Pursuant to Section 102(b)(7) of the Delaware General Corporation Law, our amended and restated certificate of incorporation eliminates the personal liability of a director to us or our stockholders for monetary damages for a breach of fiduciary duty as a director, except for liabilities arising:

•

from any breach of the director's duty of loyalty to us or our stockholders;

•

from acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law;

•

under Section 174 of the Delaware General Corporation Law; and

•

from any transaction from which the director derived an improper personal benefit.

        The above discussion of Section 145 of the Delaware General Corporation Law and of our amended and restated certificate of incorporation and bylaws is not intended to be exhaustive and is respectively qualified in its entirety by Section 145 of the Delaware General Corporation Law, our amended and restated certificate of incorporation and bylaws.

        As permitted by Section 145 of the Delaware General Corporation Law, we will carry primary and excess insurance policies insuring our directors and officers against certain liabilities they may incur in

II-1

their capacity as directors and officers. Under the policies, the insurer, on our behalf, may also pay amounts for which we granted indemnification to our directors and officers.

        In addition, the underwriting agreement to be filed as Exhibit 1.1 to this Registration Statement provides that the underwriters will indemnify us and our executive officers and directors for certain liabilities related to this offering, including liabilities arising under the Securities Act.

ITEM 15.    Recent Sales of Unregistered Securities

        In connection with our incorporation on April 1, 2013 under the laws of the State of Delaware, we issued 1,000 shares of our common stock to Athlon Holdings GP LLC for an aggregate purchase price of $10.00. These securities were offered and sold by us in reliance upon the exemption from the registration requirements provided by Section 4(2) of the Securities Act.

        On April 26, 2013, in connection with our reorganization transactions, certain holders of interests in Athlon Holdings LP exchanged their Class A limited partner interests and Class B interests of Athlon Holdings for an aggregate of 960,907 shares of our common stock. These securities were issued by us in reliance upon the exemption from the registration requirements provided by Section 4(2) of the Securities Act.

ITEM 16.    Exhibits and Financial Statement Schedules

(a)

Exhibits

Exhibit Number		Description
	1.1**	Form of Underwriting Agreement.
	3.1*	Form of Amended and Restated Certificate of Incorporation of Athlon Energy Inc.
	3.2*	Form of Amended and Restated Bylaws of Athlon Energy Inc.
	4.1*	Indenture between Wells Fargo Bank, N.A. and Athlon Holdings LP dated April 17, 2013 relating to the 73/8% Senior Notes due 2021 (including form of Note) (previously filed as exhibit 4.2 to this registration statement on June 5, 2013).
	4.2*	Registration Rights Agreement among Athlon Holdings LP, Athlon Finance Corp. and Merrill Lynch, Pierce, Fenner & Smith Incorporated dated April 17, 2013 relating to the 73/8% Senior Notes due 2021 (previously filed as exhibit 4.3 to this registration statement on June 5, 2013).
	5.1	Form of Opinion of Latham & Watkins LLP as to the legality of the securities being registered.
	10.1*	Amended and Restated Credit Agreement, dated as of March 19, 2013, among Athlon Holdings LP, Bank of America, N.A., as Administrative Agent and L/C Issuer, and the lenders party thereto.
	10.2*	Borrowing Base Redetermination and First Amendment to Amended and Restated Guarantee Agreement, dated as of May 31, 2013 by and among Athlon Holdings LP, Bank of America, N.A., as Administrative Agent and L/C Issuer, and the lenders party thereto.
	10.3+	Form of Employment Agreement between Athlon Holdings LP and Robert C. Reeves.
	10.4+	Form of Employment Agreement between Athlon Holdings LP and Officers other than Robert C. Reeves.
	10.5+	Form of Athlon Energy Inc. 2013 Incentive Award Plan.
	10.6*+	Form of Director and Officer Indemnification Agreement between Athlon Energy Inc. and each of the officers and directors thereof (previously filed as exhibit 10.12 to Amendment No. 1 to this registration statement on June 27, 2013).
	10.7*	Form of Tax Receivable Agreement by and among Athlon Energy Inc., Athlon Holdings LP and each of the Partners named therein (previously filed as exhibit 10.13 to Amendment No. 1 to this registration statement on June 27, 2013).

II-2

Exhibit Number		Description
	10.8*	Form of Exchange Agreement by and among Athlon Energy Inc. and each of the Partners named therein (previously filed as exhibit 10.14 to Amendment No. 1 to this registration statement on June 27, 2013).
	10.9	Form of Stockholders Agreement by and among Athlon Energy Inc. and those stockholders named therein.
	10.10	Form of Advisory Services and Transaction Fee Termination Agreement by and among Athlon Holdings LP, Apollo Management VII, L.P. and Apollo Global Securities, LLC.
	10.11	Form of Amended and Restated Agreement of Limited Partnership of Athlon Holdings LP.
	21.1	Subsidiaries of Athlon Energy Inc.
	23.1	Consent of Ernst & Young LLP.
	23.2	Consent of UHY LLP.
	23.3	Consent of Cawley, Gillespie & Associates, Inc.
	23.4	Consent of Latham & Watkins LLP (included in Exhibit 5.1).
	23.5*	Consent of Director Nominee.
	24.1*	Power of Attorney.
	99.1*	Report of Cawley, Gillespie & Associates, Inc. for Athlon Energy Operating LLC's proved reserves at December 31, 2011 dated as of February 20, 2012.
	99.2*	Report of Cawley, Gillespie & Associates, Inc. for Athlon FE Operating LLC's proved reserves at December 31, 2011 dated as of February 20, 2012.
	99.3*	Report of Cawley, Gillespie & Associates, Inc. for Athlon Holdings LP's proved reserves at December 31, 2012 dated as of February 15, 2013.

^*

Previously filed.

^**

To be filed by amendment.

⁺

Management contract or compensatory plan, contract or arrangement.

ITEM 17.    Undertakings

        The undersigned registrant hereby undertakes to provide to the underwriters at the closing specified in the underwriting agreement certificates in such denominations and registered in such names as required by the underwriters to permit prompt delivery to each purchaser.

        Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.

        The undersigned registrant hereby undertakes that:

(1)

For purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act of 1933 shall be deemed to be part of this registration statement as of the time it was declared effective.



(2)

For the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

II-3

SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized in the City of Fort Worth, State of Texas, on July 12, 2013.

Athlon Energy Inc.
By:	/s/ ROBERT C. REEVES Robert C. Reeves President, Chief Executive Officer and Director

        Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed below by the following persons in the capacities and the dates indicated.

Signature		Title	Date
	/s/ ROBERT C. REEVES Robert C. Reeves	President, Chief Executive Officer and Director (Principal Executive Officer)	July 12, 2013
	* William B. D. Butler	Vice President and Chief Financial Officer (Principal Financial Officer)	July 12, 2013
	* John C. Souders	Vice President and Controller (Principal Accounting Officer)	July 12, 2013
	* Gregory A. Beard	Director	July 12, 2013
	* Sam Oh	Director	July 12, 2013
	* Rakesh Wilson	Director	July 12, 2013
*By:	/s/ ROBERT C. REEVES Robert C. Reeves Attorney-in-fact

II-4

INDEX TO EXHIBITS

Exhibit Number		Description
	1.1**	Form of Underwriting Agreement.
	3.1*	Form of Amended and Restated Certificate of Incorporation of Athlon Energy Inc.
	3.2*	Form of Amended and Restated Bylaws of Athlon Energy Inc.
	4.1*	Indenture between Wells Fargo Bank, N.A. and Athlon Holdings LP dated April 17, 2013 relating to the 73/8% Senior Notes due 2021 (including form of Note) (previously filed as exhibit 4.2 to this registration statement on June 5, 2013).
	4.2*	Registration Rights Agreement among Athlon Holdings LP, Athlon Finance Corp. and Merrill Lynch, Pierce, Fenner & Smith Incorporated dated April 17, 2013 relating to the 73/8% Senior Notes due 2021 (previously filed as exhibit 4.3 to this registration statement on June 5, 2013).
	5.1	Form of Opinion of Latham & Watkins LLP as to the legality of the securities being registered.
	10.1*	Amended and Restated Credit Agreement, dated as of March 19, 2013, among Athlon Holdings LP, Bank of America, N.A., as Administrative Agent and L/C Issuer, and the lenders party thereto.
	10.2*	Borrowing Base Redetermination and First Amendment to Amended and Restated Guarantee Agreement, dated as of May 31, 2013 by and among Athlon Holdings LP, Bank of America, N.A., as Administrative Agent and L/C Issuer, and the lenders party thereto.
	10.3+	Form of Employment Agreement between Athlon Holdings LP and Robert C. Reeves.
	10.4+	Form of Employment Agreement between Athlon Holdings LP and Officers other than Robert C. Reeves.
	10.5+	Form of Athlon Energy Inc. 2013 Incentive Award Plan.
	10.6*+	Form of Director and Officer Indemnification Agreement between Athlon Energy Inc. and each of the officers and directors thereof (previously filed as exhibit 10.12 to Amendment No. 1 to this registration statement on June 27, 2013).
	10.7*	Form of Tax Receivable Agreement by and among Athlon Energy Inc., Athlon Holdings LP and each of the Partners named therein (previously filed as exhibit 10.13 to Amendment No. 1 to this registration statement on June 27, 2013).
	10.8*	Form of Exchange Agreement by and among Athlon Energy Inc. and each of the Partners named therein (previously filed as exhibit 10.14 to Amendment No. 1 to this registration statement on June 27, 2013).
	10.9	Form of Stockholders Agreement by and among Athlon Energy Inc. and those stockholders named therein.
	10.10	Form of Advisory Services and Transaction Fee Termination Agreement by and among Athlon Holdings LP, Apollo Management VII, L.P. and Apollo Global Securities, LLC.
	10.11	Form of Amended and Restated Agreement of Limited Partnership of Athlon Holdings LP.
	21.1	Subsidiaries of Athlon Energy Inc.
	23.1	Consent of Ernst & Young LLP.
	23.2	Consent of UHY LLP.
	23.3	Consent of Cawley, Gillespie & Associates, Inc.
	23.4	Consent of Latham & Watkins LLP (included in Exhibit 5.1).
	23.5*	Consent of Director Nominee.
	24.1*	Power of Attorney.
	99.1*	Report of Cawley, Gillespie & Associates, Inc. for Athlon Energy Operating LLC's proved reserves at December 31, 2011 dated as of February 20, 2012.
	99.2*	Report of Cawley, Gillespie & Associates, Inc. for Athlon FE Operating LLC's proved reserves at December 31, 2011 dated as of February 20, 2012.
	99.3*	Report of Cawley, Gillespie & Associates, Inc. for Athlon Holdings LP's proved reserves at December 31, 2012 dated as of February 15, 2013.

^*

Previously filed.

^**

To be filed by amendment.

⁺

Management contract or compensatory plan, contract or arrangement.

II-5

EX-5.1

Exhibit 5.1

	811 Main Street, Suite 3700 Houston, TX 77002 Tel: +1.713.546.5400 Fax: +1.713.546.5401 www.lw.com
	FIRM / AFFILIATE OFFICES
	Abu Dhabi	Milan
	Barcelona	Moscow
	Beijing	Munich
	Boston	New Jersey
	Brussels	New York
	Chicago	Orange County
	Doha	Paris
	Dubai	Riyadh
	Düsseldorf	Rome
	Frankfurt	San Diego
	Hamburg	San Francisco
	Hong Kong	Shanghai
	Houston	Silicon Valley
	London	Singapore
	Los Angeles	Tokyo
	Madrid	Washington, D.C.

                        , 2013

Athlon Energy Inc.
420 Throckmorton Street,
Suite 1200
Fort Worth, Texas 76102

Re:

Form S-1 Registration Statement File No. 333-189109
Initial Public Offering of up to                   Shares of Common Stock of Athlon Energy Inc.

Ladies and Gentlemen:

        We have acted as special counsel to Athlon Energy Inc., a Delaware corporation (the "Company"), in connection with the proposed issuance of up to shares of common stock, $0.01 par value per share (the "Shares"). The Shares are included in a registration statement on Form S-1 under the Securities Act of 1933, as amended (the "Act"), filed with the Securities and Exchange Commission (the "Commission") on June 5, 2013 (Registration No. 333-189109) (,as amended, the "Registration Statement"). The term "Shares" shall include any additional shares of common stock registered by the Company pursuant to Rule 462(b) under the Act in connection with the offering contemplated by the Registration Statement. This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement or related Prospectus (the "Prospectus"), other than as expressly stated herein with respect to the issue of the Shares.

        As such counsel, we have examined such matters of fact and questions of law as we have considered appropriate for purposes of this letter. With your consent, we have relied upon certificates and other assurances of officers of the Company and others as to factual matters without having independently verified such factual matters. We are opining herein as to General Corporation Law of the State of Delaware (the "Delaware Act"), and we express no opinion with respect to any other laws.

        Subject to the foregoing and the other matters set forth herein, it is our opinion that, as of the date hereof, when the Shares shall have been duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the purchasers and have been issued by the Company

July     , 2013
Page 2

against payment therefor (not less than par value) in the circumstances contemplated by the form of underwriting agreement most recently filed as an exhibit to the Registration Statement, the issue and sale of the Shares will have been duly authorized by all necessary corporate action of the Company, and the Shares will be validly issued, fully paid and nonassessable. In rendering the foregoing opinion, we have assumed that the Company will comply with all applicable notice requirements regarding uncertificated shares provided in the Delaware Act.

        This opinion is for your benefit in connection with the Registration Statement and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions of the Act. We consent to your filing this opinion as an exhibit to the Registration Statement and to the reference to our firm in the Prospectus under the heading "Legal Matters." We further consent to the incorporation by reference of this letter and consent into any registration statement filed pursuant to Rule 462(b) with respect to the Shares. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

Very truly yours,

EX-10.3

Exhibit 10.3

Employment Agreement

This Employment Agreement (the “Agreement”), dated as of                   , 2013 (the “Effective Date”), is made by and between Athlon Holdings LP, a Delaware limited partnership (together with any successor thereto, the “Company”), and Robert C. Reeves (the “Executive”) (collectively referred to herein as the “Parties”).

RECITALS

A.It is the desire of the Company to assure itself of the services of the Executive to the Company by entering into this Agreement.

B.Executive and the Company mutually desire that Executive provide services to the Company on the terms herein provided.

AGREEMENT

NOW, THEREFORE, in consideration of the foregoing and of the respective covenants and agreements set forth below, the Parties hereto agree as follows:

1.Employment.

(a)General.  The Company shall employ Executive and Executive shall enter the employ of the Company, for the period and in the position set forth in this Section 1, and upon the other terms and conditions herein provided.

(b)Employment Term.  The term of employment under this Agreement (the “Term”) shall be for the period beginning on the Effective Date, and ending on the third anniversary thereof, subject to earlier termination as provided in Section 3.  The Term shall automatically renew for additional one (1) year periods unless no later than ninety (90) days prior to the end of the otherwise applicable Term either party gives written notice of non-renewal (“Notice of Non-Renewal”) to the other, in which case Executive’s employment will terminate at the end of the then-applicable Term or any other date set by the Company in accordance with Section 3 and subject to earlier termination as provided in Section 3.

(c)Position and Duties.  Executive shall serve as the Chief Executive Officer and President of the Company.  Executive shall devote substantially all of his time and attention during normal business hours to the business of the Company, provided that Executive shall be permitted to (i) manage Executive’s personal, financial and legal affairs, (ii) participate in trade associations, and (iii) serve on the board of directors of not-for-profit or tax-exempt charitable organizations, in each case, subject to compliance with this Agreement and provided that such activities do not materially interfere with Executive’s performance of Executive’s duties and responsibilities hereunder.  Executive will act in the best interest of the Company while performing his duties for the Company and will perform with due care his duties and responsibilities for the Company. Executive’s duties will include those normally incidental to the position of President and Chief Executive Officer as well as whatever additional duties may be assigned to him by the Board of Supervisors of the Company (the “Board”). Executive agrees to cooperate with the Board and not to engage in any activity that materially interferes with the

performance of Executive’s duties hereunder. During the Term, Executive will not hold outside employment, provided, that it shall not be a violation of this Agreement for Executive to (i) serve on corporate, civic and charitable boards or committees (except for boards or committees of a business organization that competes with the Company in any business in which the Company is regularly engaged) or (ii) manage or engage in other activities in connection with Executive’s personal investments; provided, further, that the foregoing permitted activities shall not materially interfere with Executive’s duties hereunder. Executive acknowledges and agrees that Executives owes the Company a duty of loyalty and that the obligations described in this Agreement are in addition to, and not in lieu of, the obligations Executive owes the Company under the common law.

2.Compensation and Related Matters.

(a)Annual Base Salary.  During the Term, Executive shall receive a base salary at a rate of $570,000 per annum (the “Annual Base Salary”), which shall be paid in accordance with the customary payroll practices of the Company.  Such Annual Base Salary shall be reviewed from time to time by the Board or an authorized committee of the Board, provided that such Annual Base Salary shall not be reduced.

(b)Bonus and Equity Compensation.  During the Term, the Executive will be eligible to participate in an incentive bonus program and an equity incentive plan established by the Board.  Executive’s target annual bonus under the incentive bonus program shall be 100% of Annual Base Salary (the “Target Bonus”).  The bonus awards payable under the incentive program shall be based on the achievement of performance goals to be set by the Board after consultation with Executive and finally determined by the Board or its designee. Bonuses will be paid no later than March 15th of the calendar year following the calendar year in which the applicable bonus is earned.

(c)Benefits.  During the Term, Executive may participate in such employee and executive benefit plans and programs as the Company may from time to time offer to provide to its employees and executives, pursuant to the terms and eligibility requirements of those plans; provided, however, Executive shall not be eligible to participate in a Company plan that provides medical, dental or life insurance benefits to the extent such Company plan is substantially comparable to one of the plans sponsored by Executive’s previous employer that Executive participates in as of the Effective Date, unless and until Executive ceases to participate in such substantially comparable plan of his previous employer.

(d)Vacation.  During the Term, Executive shall be entitled to paid vacation in accordance with the Company’s vacation policy, as it may be amended from time to time, provided, that Executive shall receive no less than four (4) weeks of paid annual vacation and shall be permitted to carry over accrued but unused vacation in accordance with the Company’s vacation policy, and provided, further, that notwithstanding the Company’s vacation policy, Executive shall be permitted to carry over two weeks of accrued but unused vacation per year.  Any vacation shall be taken at the reasonable and mutual convenience of the Company and Executive.

(e)Expenses.  During the Term, the Company shall reimburse Executive for all reasonable travel and other business expenses incurred by Executive in the performance of Executive’s duties to the Company in accordance with the Company’s expense reimbursement policy.

(f)Key Person Insurance.  At any time during the Term, the Company shall have the right to insure the life of Executive for the Company’s sole benefit.  The Company shall have the right to determine the amount of insurance and the type of policy.  Executive shall reasonably cooperate with the Company in obtaining such insurance by submitting to physical examinations, by supplying all information reasonably required by any insurance carrier, and by executing all necessary documents reasonably required by any insurance carrier.

3.Termination.

Executive’s employment hereunder may be terminated by the Company or Executive, as applicable, without any breach of this Agreement under the following circumstances:

(a)Circumstances.

(i)Death.  Executive’s employment hereunder shall terminate upon Executive’s death.

(ii)Disability.  If Executive has incurred a Disability, as defined below, the Company may terminate Executive’s employment.

(iii)Termination for Cause.  The Company may terminate Executive’s employment for Cause, as defined below.

(iv)Termination without Cause.  The Company may terminate Executive’s employment without Cause.

(v)Resignation from the Company for Good Reason.  Executive may resign Executive’s employment with the Company for Good Reason, as defined below.

(vi)Resignation from the Company Without Good Reason.  Executive may resign Executive’s employment with the Company for any reason other than Good Reason or for no reason.

(vii)Non-extension of Term by the Company.  The Company may give notice of non-extension to Executive pursuant to Section 1.

(viii)Non-extension of Term by Executive.  Executive may give notice of non-extension to the Company pursuant to Section 1.

(b)Notice of Termination.  Any termination of Executive’s employment by the Company or by Executive under this Section 3 (other than termination pursuant to paragraph (a)(i)) shall be communicated by a written notice to the other party hereto (i) indicating the specific termination provision in this Agreement relied upon, (ii) setting forth in reasonable

detail the facts and circumstances claimed to provide a basis for termination of Executive’s employment under the provision so indicated, and (iii) specifying a Date of Termination which, if submitted by Executive, shall be at least thirty (30) days following the date of such notice (a “Notice of Termination”); provided, however, that in the event that Executive delivers a Notice of Termination to the Company, the Company may, in its sole discretion, change the Date of Termination to any date that occurs following the date of Company’s receipt of such Notice of Termination and is prior to the date specified in such Notice of Termination.  A Notice of Termination submitted by the Company may provide for a Date of Termination on the date Executive receives the Notice of Termination, or any date thereafter elected by the Company in its sole discretion.  The failure by the Company to set forth in the Notice of Termination any fact or circumstance which contributes to a showing of Cause shall not waive any right of the Company hereunder or preclude the Company from asserting such fact or circumstance in enforcing the Company’s rights hereunder.

(c)Company Obligations upon Termination.  Upon termination of Executive’s employment pursuant to any of the circumstances listed in Section 3, Executive (or Executive’s estate) shall be entitled to receive the sum of:  (i) the portion of Executive’s Annual Base Salary earned through the Date of Termination, but not yet paid to Executive, plus any accrued vacation earned through the Date of Termination, but not used by Executive; (ii) any annual bonus earned by not yet paid to Executive, (iii) any expenses owed to Executive pursuant to Section 2(e); and (iv) any amount accrued and arising from Executive’s participation in, or benefits accrued under any employee benefit plans, programs or arrangements, which amounts shall be payable in accordance with the terms and conditions of such employee benefit plans, programs or arrangements (collectively, the “Company Arrangements”).  Except as otherwise expressly required by law (e.g., COBRA) or as specifically provided herein, all of Executive’s rights to salary, severance, benefits, bonuses and other amounts hereunder (if any) shall cease upon the termination of Executive’s employment hereunder.  In the event that Executive’s employment is terminated by the Company for any reason, Executive’s sole and exclusive remedy shall be to receive the severance payments and benefits described in this Section 3(c) or Section 4, as applicable.

(d)Deemed Resignation.  Upon termination of Executive’s employment for any reason, Executive shall be deemed to have resigned from all offices and directorships, if any, then held with the Company or any of its affiliates.

4.Severance Payments.

(a)Termination for Cause, Resignation from the Company Without Good Reason,  Non-extension of Term by Executive.  If Executive’s employment shall terminate pursuant to Section 3(a)(iii) for Cause, pursuant to Section 3(a)(vi) for Executive’s resignation from the Company without Good Reason, or for no reason, pursuant to Section 3(a)(viii) due to non-extension of the Term by Executive, Executive shall not be entitled to any severance payments or benefits, except as provided in Section 3(c).

(b)Termination without Cause, Resignation With Good Reason or Termination upon Non-Extension of the Term by the Company.  If Executive’s employment shall terminate without Cause pursuant to Section 3(a)(iv), pursuant to Section 3(a)(v) due to Executive’s

resignation for Good Reason, or pursuant to Section 3(a)(vii) due to non-extension of the Term by the Company, then, subject to Executive signing on or before the 45th day following Executive’s Separation from Service (as defined below), and not revoking, a release of claims in the form attached as Exhibit A to this Agreement (the “Release”), and Executive’s continued compliance with Sections 5 and 6, Executive shall receive, in addition to payments and benefits set forth in Section 3(c), the following:

(i)An amount in cash equal to four times the Annual Base Salary in effect as of the Date of Termination (without regard to any reduction that triggers a termination for Good Reason), payable (Y) with respect to 50% of such amount, in a lump sum on the sixtieth (60) day following the date of Executive’s Separation from Service, and (X) with respect to 50% of such amount, over 12 months in arrears commencing on the sixtieth (60) day following the date of Executive’s Separation from Service in accordance with the Company’s regular payroll practice; and

(ii)If Executive elects to receive continued healthcare coverage pursuant to the Consolidated Omnibus Budget Reconciliation Act of 1985, as amended (“COBRA”), the Company shall directly pay, or reimburse Executive for, the COBRA premiums for Executive and Executive’s covered dependents during the period commencing on Executive’s Separation from Service and ending on the earliest of (X) the last day of the applicable COBRA period, or (Y) the second anniversary of the Date of Termination.

In the event Executive fails to sign the Release within 45 days, or revokes the Release, then Executive will not be entitled to receive the additional consideration in subparts (i) and (ii).

(c)Termination Due to Disability or Death.  If Executive’s employment shall terminate as a result of Executive’s death pursuant to Section 3(a)(i) or Disability pursuant to Section 3(a)(ii), then, subject to, in the case of termination due to Disability, Executive signing on or before the 45th day following Executive’s Separation from Service (as defined below), and not revoking, the Release, and, in the case of termination due to Disability, Executive’s continued compliance with Sections 5 and 6, Executive (or his estate) shall receive, in addition to payments and benefits set forth in Section 3(c), the following:

(i)an amount in cash equal to 3/12 of the Annual Base Salary in effect as of the Date of Termination, payable in a lump sum on the sixtieth (60) day following the date of Executive’s Separation from Service; and

(ii)if Executive (or any of his dependents) elects to receive continued healthcare coverage pursuant to COBRA, the Company shall directly pay, or reimburse Executive (or his dependents) for, the COBRA premiums for Executive and Executive’s covered dependents during the period commencing on Executive’s Separation from Service and ending three (3) months thereafter.

In the event Executive fails to sign the Release within 45 days, or revokes the Release, in the case of termination due to Disability, then Executive will not be entitled to receive the additional consideration in subparts (i) and (ii).

(d)Change in Control.  Notwithstanding anything to the contrary in Section 4(b), in

the event Executive’s employment terminates without Cause pursuant to Section 3(a)(iv), due to Executive’s resignation for Good Reason pursuant to Section 3(a)(v) or pursuant to Section 3(a)(vii) due to non-extension of the Term by the Company, in any case, within one year following the date of a Change in Control, with respect to Section 4(b)(i), in lieu of the amount specified therein, Executive shall be entitled to receive an amount in cash equal to three (3) times the Annual Base Salary, plus three (3) times the greater of the average of the Executive’s previous two years’ annual bonus payments or the Target Bonus, which cash payment shall be paid in a single lump sum within 30 days after the Executive’s Separation from Service if the Change in Control also constitutes a “change in control event” within the meaning of Treasury Regulation Section 1.409A-3(i)(5).

(e)No Mitigation; Survival.  Executive shall not be required to mitigate the amount of any payment provided for under this Agreement by seeking other employment or in any other manner.  Notwithstanding anything to the contrary in this Agreement, the provisions of Sections 5 through 9 and Section 11 will survive the termination of Executive’s employment and the expiration or termination of the Term.

5.Competition.  Executive acknowledges that the Company has provided and the Company agrees to continue to provide Executive with access to its confidential, proprietary, and/or trade secret information, including confidential information of third parties such as customers, suppliers, and business affiliates; specialized training and knowledge regarding the Company’s methodologies and business strategies; and/or support in the development of goodwill such as introductions and customer relationship information. The foregoing is not contingent on continued employment, but upon Executive’s use of the access, specialized training, and/or goodwill support provided by Company for the exclusive benefit of the Company and upon Executive’s full compliance with the restrictions on Executive’s conduct provided for in this Agreement.  Ancillary to the rights provided to Executive as set forth in this Agreement, the Company’s provision of confidential, proprietary, and/or trade secret information, specialized training, and/or goodwill support to Executive, and Executive’s agreements regarding the use of same, in order to protect the value of any equity-based compensation, training, goodwill support and/or the confidential information described above, the Company and Executive agree to the following provisions against unfair competition, which Executive acknowledges represent a fair balance of the Company’s rights to protect its business and Executive’s right to pursue employment:

(a)Executive shall not, at any time during the Restriction Period, directly or indirectly engage in, have any equity interest in, interview for a potential employment or consulting relationship with or manage or operate any person, firm, corporation, partnership or business (whether as director, officer, employee, agent, representative, partner, security holder, consultant or otherwise) that engages in any business which competes with any portion of the Business (as defined below) of the Company in the United States; provided, however, in the event the Company terminates Executive’s employment without Cause or Executive resigns for Good Reason, the post-termination restrictions set forth in this Section 5(a) shall be limited to the following: (a) Executive shall not, at any time during the Restriction Period following the Date of Termination, directly or indirectly engage in, have any equity interest in, interview for a potential employment or consulting relationship with or manage or operate any person, firm, corporation, partnership or business (whether as director, officer, employee, agent,

representative, partner, security holder, consultant or otherwise) that engages in any business which competes in any material respect with any material portion of the Business (as defined below) of the Company within twenty-five (25) miles of (i) any oil or natural gas assets of the Company or (ii) any potential oil or natural gas assets where the Company has taken material steps to lease or purchase real property with respect to such potential assets within the six (6) month period immediately prior to the Date of Termination; provided, that the Company provides Executive with a written list of any such potential leases or real property within five (5) days following the Date of Termination.  Nothing herein shall prohibit Executive from being a passive owner of not more than 2% of the outstanding equity interest in any entity that is publicly traded, so long as Executive has no active participation in the business of such entity.

(b)Executive shall not, at any time during the Restriction Period, directly or indirectly, recruit or otherwise solicit or induce any employee, customer, subscriber or supplier of the Company (i) to terminate its employment or arrangement with the Company, or (ii) to otherwise change its relationship with the Company. Executive shall not, at any time during the Restriction Period, directly or indirectly, either for Executive or for any other person or entity, (x) solicit any employee of the Company to terminate his or her employment with the Company, (y) employ any such individual during his or her employment with the Company and for a period of six months after such individual terminates his or her employment with the Company or (z) solicit or service any person who was a customer, supplier, licensee, licensor or other business relation of the Company in order to induce or attempt to induce such person to cease doing business with, or reduce the amount of business conducted with, the Company, or in any way interfere with the relationship between any such customer, supplier, licensee, licensor or other business relation of the Company.

(c)In the event the terms of this Section 5 shall be determined by any court of competent jurisdiction to be unenforceable by reason of its extending for too great a period of time or over too great a geographical area or by reason of its being too extensive in any other respect, it will be interpreted to, and may be modified by a court of competent jurisdiction to, extend only over the maximum period of time for which it may be enforceable, over the maximum geographical area as to which it may be enforceable, or to the maximum extent in all other respects as to which it may be enforceable, all as determined by such court in such action.

(d)As used in this Section 5, (i) the term “Company” shall include the Company and its direct and indirect parents and subsidiaries; (ii) the term “Business” shall mean the business of the Company and shall include the acquisition, exploration, exploitation and development of, oil and natural gas assets, and the acquisition of leases and other real property in connection therewith, as such business may be expanded or altered by the Company during the Term; and (iii) the term “Restriction Period” shall mean the period beginning on the Effective Date and ending on the date twelve (12) months following the Date of Termination, except that if Executive’s termination of employment occurs within one year following a Change in Control, Restriction Period shall mean the period beginning on the Effective Date and ending on the date six (6) months following the Date of Termination.

(e)Executive agrees, during the Term and following the Date of Termination, to refrain from disparaging the Company and its affiliates, including any of its services, technologies or practices, or any of its directors, officers, agents, representatives or stockholders,

either orally or in writing.  Nothing in this paragraph shall preclude Executive from making truthful statements that are reasonably necessary to comply with applicable law, regulation or legal process.

(f)Company agrees, during the Term and following the Date of Termination, to refrain from disparaging the Executive, including any of Executive’s services or practices, either orally or in writing.  Nothing in this paragraph shall preclude Company from making truthful statements that are reasonably necessary to comply with applicable law, regulation or legal process.

(g)Executive represents that Executive’s employment by the Company does not and will not breach any agreement with any former employer, including any non-compete agreement or any agreement to keep in confidence or refrain from using information acquired by Executive prior to Executive’s employment by the Company.  During Executive’s employment by the Company, Executive agrees that Executive will not violate any non-solicitation agreements Executive entered into with any former employer or improperly make use of, or disclose, any information or trade secrets of any former employer or other third party, nor will Executive bring onto the premises of the Company or use any unpublished documents or any property belonging to any former employer or other third party, in violation of any lawful agreements with that former employer or third party.

(h)Tolling.  In the event Executive engages in conduct in violation of his covenants in Sections 5(a) or (b), the Restriction Period shall be extended for a period of time equal to the time in which Executive engaged in competitive activity prohibited by this Agreement.

6.Nondisclosure of Proprietary Information.

(a)Except in connection with the faithful performance of Executive’s duties hereunder or pursuant to Section 6(c) and (e), Executive shall, during the Term and for twenty-four months thereafter, maintain in confidence and shall not directly, indirectly or otherwise, use, disseminate, disclose or publish, or use for Executive’s benefit or the benefit of any person, firm, corporation or other entity any confidential or proprietary information or trade secrets of the Company (including, without limitation, business plans, business strategies and methods, acquisition targets, intellectual property in the form of patents, trademarks and copyrights and applications therefor, ideas, inventions, works, discoveries, improvements, information, documents, formulae, practices, processes, methods, developments, source code, modifications, technology, techniques, data, programs, other know-how or materials, owned, developed or possessed by the Company, whether in tangible or intangible form, information with respect to the Company’s operations, processes, products, inventions, business practices, finances, principals, vendors, suppliers, customers, potential customers, marketing methods, costs, prices, contractual relationships, regulatory status, prospects and compensation paid to employees or other terms of employment) (collectively, the “Confidential Information”), or deliver to any person, firm, corporation or other entity any document, record, notebook, computer program or similar repository of or containing any such Confidential Information.  The Parties hereby stipulate and agree that, as between them, any item of Confidential Information is important, material and confidential and affects the successful conduct of the businesses of the Company

(and any successor or assignee of the Company).  Notwithstanding the foregoing, Confidential Information shall not include any information that is generally known in the oil and gas industry, was known by Executive prior to his employment with the Company or has been published in a form generally available to the public prior to the date Executive proposes to disclose or use such information, provided, that such publishing of the Confidential Information shall not have resulted from Executive directly or indirectly breaching Executive’s obligations under this Section 6(a) or any other similar provision by which Executive is bound, or from any third-party breaching a provision similar to that found under this Section 6(a).  For the purposes of the previous sentence, Confidential Information will not be deemed to have been published or otherwise disclosed merely because individual portions of the information have been separately published, but only if all material features comprising such information have been published in combination.

(b)Upon termination of Executive’s employment with the Company for any reason, Executive will promptly deliver to the Company all correspondence, drawings, manuals, letters, notes, notebooks, reports, programs, plans, proposals, financial documents, or any other documents or property concerning the Company’s customers, business plans, marketing strategies, products, property or processes.

(c)Executive may respond to a lawful and valid subpoena or other legal process but shall give the Company the earliest possible notice thereof, shall, as much in advance of the return date as possible, make available to the Company and its counsel the documents and other information sought and shall assist such counsel at Company’s expense in resisting or otherwise responding to such process.

(d)As used in this Section 6 and Section 7, the term “Company” shall include the Company and its direct and indirect parents and subsidiaries.

(e)Nothing in this Agreement shall prohibit Executive from (i) disclosing information and documents when required by law, subpoena or court order (subject to the requirements of Section 6(c) above), (ii) disclosing information and documents to Executive’s attorney or tax adviser for the purpose of securing legal or tax advice, (iii) disclosing Executive’s post-employment restrictions in this Agreement in confidence to any potential new employer, or (iv) retaining, at any time, Executive’s personal correspondence, Executive’s personal contacts and documents related to Executive’s own personal benefits, entitlements and obligations.

7.Inventions.

All rights to discoveries, inventions, improvements and innovations (including all data and records pertaining thereto) related to the business of the Company, whether or not patentable, copyrightable, registrable as a trademark, or reduced to writing, that Executive may discover, invent or originate during the Term, either alone or with others and whether or not during working hours or by the use of the facilities of the Company (“Inventions”), shall be the exclusive property of the Company.  Executive shall promptly disclose all Inventions to the Company, shall execute at the request of the Company any assignments or other documents the Company may deem reasonably necessary to protect or perfect its rights therein, and shall assist the Company, upon reasonable request and at the Company’s expense, in obtaining, defending

and enforcing the Company’s rights therein. Executive hereby appoints the Company as Executive’s attorney-in-fact to execute on Executive’s behalf any assignments or other documents reasonably deemed necessary by the Company to protect or perfect its rights to any Inventions.

8.Injunctive Relief.

It is recognized and acknowledged by Executive that a breach of the covenants contained in Sections 5, 6 and 7 will cause irreparable damage to Company and its goodwill, the exact amount of which will be difficult or impossible to ascertain, and that the remedies at law for any such breach will be inadequate.  Accordingly, Executive agrees that in the event of a breach of any of the covenants contained in Sections 5, 6 and 7, in addition to any other remedy which may be available at law or in equity, the Company will be entitled to specific performance and injunctive relief without the need to post bond.

9.Assignment and Successors.

The Company may assign its rights and obligations under this Agreement to any successor to all or substantially all of the business or the assets of the Company (by merger or otherwise), and may assign or encumber this Agreement and its rights hereunder as security for indebtedness of the Company and its affiliates.  This Agreement shall be binding upon and inure to the benefit of the Company, Executive and their respective successors, assigns, personnel and legal representatives, executors, administrators, heirs, distributees, devisees, and legatees, as applicable.  None of Executive’s rights or obligations may be assigned or transferred by Executive, other than Executive’s rights to payments hereunder, which may be transferred only by will or operation of law.  Notwithstanding the foregoing, Executive shall be entitled, to the extent permitted under applicable law and applicable Company Arrangements, to select and change a beneficiary or beneficiaries to receive compensation hereunder following Executive’s death by giving written notice thereof to the Company.

10.Certain Definitions.

(a)Cause.  “Cause” shall mean the occurrence or existence of any of the following events:

(i)Executive’s having willfully engaged in an act of fraud, embezzlement or misappropriation against the Company or its affiliates;

(ii)Executive’s having willfully engaged in misconduct that he knew, based on facts known to him, could reasonably be expected to be materially injurious to the Company or its affiliates;

(iii)Executive’s material breach of this Agreement;

(iv)Executive’s having been convicted of, or having entered a plea bargain or settlement admitting guilt for, any felony, under the laws of the United States, any state or the District of Columbia; or

(v)Executive’s having been the subject of any order, judicial or administrative, obtained or issued by the Securities and Exchange Commission, for any securities violation involving fraud, including, for example, any such order consented to by Executive in which findings of facts or any legal conclusions establishing liability are neither admitted nor denied.

In any case, if the Company desires to terminate Executive’s employment for Cause in accordance herewith, it shall (i) deliver to Executive a written notice authorized by a majority of the Board, specifying in detail the particulars of Executive’s conduct upon which the termination is based; and (ii) allow Executive 30 days from the date of such notice to (X) remedy, cure or rectify, if possible, the situation giving rise to the Company’s allegations of Cause or (Y) provide Executive with an opportunity to be heard by the Board (with the assistance of Executive’s counsel if Executive so desires) and have the majority of the Board adopt a resolution in good faith confirming such violation.

(b)Change in Control.  “Change in Control” shall be as defined in the Athlon Energy Inc. 2013 Incentive Award Plan, without regard to any amendments to such plan that may be adopted after the date of Athlon Energy Inc.’s initial public offering.

(c)Good Reason.  “Good Reason” shall mean the occurrence of any of the following events without Executive’s express written consent:

(i)Any reduction in Executive’s Annual Base Salary, provided that Executive specifically terminates his employment for Good Reason hereunder within 90 days from the date that he has actual notice of any such reduction;

(ii)Any material breach by the Company of this Agreement, provided that Executive specifically terminates his employment for Good Reason hereunder within 90 days from the date that he has actual notice of such material breach;

(iii)Executive’s duties or responsibilities for the Company or its successor are materially reduced or there is any material change in Executive’s title or any material change in the types of positions reporting to Executive or the type of position to whom Executive reports, provided that Executive specifically terminates his employment for Good Reason hereunder within 90 days following his receipt of actual notice of such reduction or change; or

(iv)Any transfer of Executive’s primary place of employment of more than 25 miles from 777 Main Street, Fort Worth, Texas, provided that such transfer increases Executive’s commute by more than 25 miles, and provided, further, that Executive specifically terminates his employment for Good Reason hereunder within 90 days following such transfer.

In any case, if Executive desires to terminate his employment for Good Reason in accordance herewith, he shall first give written notice of the facts and circumstances providing the basis for Good Reason to the Board, and allow the Company 30 days from the date of such notice to remedy, cure or rectify the situation giving rise to Good Reason.

(d)Date of Termination.  “Date of Termination” shall mean (i) if Executive’s employment is terminated by Executive’s death, the date of Executive’s death; (ii) if Executive’s employment is terminated pursuant to Section 3(a)(ii) – (vi), either the date indicated in the Notice of Termination or the date specified by the Company pursuant to Section 3(b), whichever is earlier; (iii) if Executive’s employment is terminated pursuant to Section 3(a)(vii) or Section 3(a)(viii), the expiration of the then-applicable Term.

(e)Disability.  “Disability” shall mean, at any time the Company or any of its affiliates sponsors a long-term disability plan for the Company’s employees,  “disability” as defined in such long-term disability plan for the purpose of determining a participant’s eligibility for benefits, provided, however, if the long-term disability plan contains multiple definitions of disability, “Disability” shall refer to that definition of disability which, if Executive qualified for such disability benefits, would provide coverage for the longest period of time. The determination of whether Executive has a Disability shall be made by the person or persons required to make disability determinations under the long-term disability plan.  At any time the Company does not sponsor a long-term disability plan for its employees, Disability shall mean Executive’s inability to perform, with or without reasonable accommodation, the essential functions of Executive’s position hereunder for a total of six months during any twelve-month period as a result of incapacity due to mental or physical illness as determined by a physician selected by the Company or its insurers and acceptable to Executive or Executive’s legal representative, with such agreement as to acceptability not to be unreasonably withheld or delayed.  Any refusal by Executive to submit to a medical examination for the purpose of determining Disability shall be deemed to constitute conclusive evidence of Executive’s Disability.

11.Miscellaneous Provisions.

(a)Defense of Claims.  Executive agrees that, during the Term and for a period of twenty-four months after the Date of Termination, upon request from the Company, Executive will cooperate with the Company and its affiliates in the defense of any claims or actions that may be made by or against the Company or any of its affiliates that affect Executive’s prior areas of responsibility, except if Executive’s reasonable interests are adverse to the Company or affiliates in such claim or action.  The Company agrees to promptly pay or reimburse Executive upon demand for all of Executive’s reasonable travel and other direct expenses incurred, or to be reasonably incurred, to comply with Executive’s obligations under this Section 11(a).

(b)Governing Law.  This Agreement shall be governed, construed, interpreted and enforced in accordance with its express terms, and otherwise in accordance with the substantive laws of the State of Texas without reference to the principles of conflicts of law of the State of Texas or any other jurisdiction, and where applicable, the laws of the United States.

(c)Validity.  The invalidity or unenforceability of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provision of this Agreement, which shall remain in full force and effect.

(d)Notices.  Any notice, request, claim, demand, document and other communication hereunder to any Party shall be effective upon receipt (or refusal of receipt) and

shall be in writing and delivered personally or sent by facsimile or certified or registered mail, postage prepaid, as follows:

(i)If to the Company:

420 Throckmorton Street, Suite 1200

Fort Worth, TX 76102

Attn:  Chief Financial Officer or General Counsel

(ii)If to Executive, at the last address that the Company has in its personnel records for Executive.

or at any other address as any Party shall have specified by notice in writing to the other Party.

(e)Counterparts.  This Agreement may be executed in several counterparts, each of which shall be deemed to be an original, but all of which together will constitute one and the same Agreement.  Signatures delivered by facsimile shall be deemed effective for all purposes.

(f)Entire Agreement.  The terms of this Agreement are intended by the Parties to be the final expression of their agreement with respect to the employment of Executive by the Company and supersede all prior understandings and agreements, whether written or oral, including any employment agreement previously entered into between Executive and Athlon Energy LP (“Prior Agreement”).  The Parties further intend that this Agreement shall constitute the complete and exclusive statement of their terms and that no extrinsic evidence whatsoever may be introduced in any judicial, administrative, or other legal proceeding to vary the terms of this Agreement.

(g)Amendments; Waivers.  This Agreement may not be modified, amended, or terminated except by an instrument in writing, signed by Executive and a duly authorized officer of Company.  By an instrument in writing similarly executed, Executive or a duly authorized officer of the Company, as applicable, may waive compliance by the other Party with any specifically identified provision of this Agreement that such other Party was or is obligated to comply with or perform; provided, however, that such waiver shall not operate as a waiver of, or estoppel with respect to, any other or subsequent failure.  No failure to exercise and no delay in exercising any right, remedy, or power hereunder preclude any other or further exercise of any other right, remedy, or power provided herein or by law or in equity.

(h)No Inconsistent Actions.  The Parties hereto shall not voluntarily undertake or fail to undertake any action or course of action inconsistent with the provisions or essential intent of this Agreement.  Furthermore, it is the intent of the Parties hereto to act in a fair and reasonable manner with respect to the interpretation and application of the provisions of this Agreement.

(i)Construction.  This Agreement shall be deemed drafted equally by both the Parties. Its language shall be construed as a whole and according to its fair meaning.  Any presumption or principle that the language is to be construed against any Party shall not apply.  The headings in this Agreement are only for convenience and are not intended to affect

construction or interpretation.  Any references to paragraphs, subparagraphs, sections or subsections are to those parts of this Agreement, unless the context clearly indicates to the contrary.  Also, unless the context clearly indicates to the contrary, (a) the plural includes the singular and the singular includes the plural; (b) “and” and “or” are each used both conjunctively and disjunctively; (c) “any,” “all,” “each,” or “every” means “any and all,” and “each and every”; (d) “includes” and “including” are each “without limitation”; (e) “herein,” “hereof,” “hereunder” and other similar compounds of the word “here” refer to the entire Agreement and not to any particular paragraph, subparagraph, section or subsection; and (f) all pronouns and any variations thereof shall be deemed to refer to the masculine, feminine, neuter, singular or plural as the identity of the entities or persons referred to may require.

(j)Arbitration.  Any controversy, claim or dispute arising out of or relating to this Agreement, shall be settled solely and exclusively by a binding arbitration process for employment claims administered by JAMS/Endispute in Fort Worth, Texas.  Such arbitration shall be conducted in accordance with the then-existing JAMS/Endispute Rules of Practice and Procedure, with the following exceptions if in conflict: (a) one arbitrator who is a retired judge shall be chosen by JAMS/Endispute; (b) each Party to the arbitration will pay its pro rata share of the expenses and fees of the arbitrator, together with other expenses of the arbitration incurred or approved by the arbitrator; and (c) arbitration may proceed in the absence of any Party if written notice (pursuant to the JAMS/Endispute rules and regulations) of the proceedings has been given to such Party.  Each Party shall bear its own attorneys fees and expenses.  The Parties agree to abide by all decisions and awards rendered in such proceedings.  Such decisions and awards rendered by the arbitrator shall be final and conclusive.  All such controversies, claims or disputes shall be settled in this manner in lieu of any action at law or equity; provided, however, that nothing in this subsection shall be construed as precluding the bringing an action for injunctive relief or specific performance as provided in this Agreement.  This dispute resolution process and any arbitration hereunder shall be confidential and neither any Party nor the neutral arbitrator shall disclose the existence, contents or results of such process without the prior written consent of all Parties.  If JAMS/Endispute no longer exists or is otherwise unavailable, the Parties agree that the American Arbitration Association (“AAA’) shall administer the arbitration in accordance with its then-existing rules for employment claims.  In such event, all references herein to JAMS/Endispute shall mean AAA.  Notwithstanding the foregoing, Executive and the Company each have the right to resolve any issue or dispute over intellectual property rights by Court action instead of arbitration.

(k)Enforcement.  If any provision of this Agreement is held to be illegal, invalid or unenforceable under present or future laws effective during the term of this Agreement, such provision shall be fully severable; this Agreement shall be construed and enforced as if such illegal, invalid or unenforceable provision had never comprised a portion of this Agreement; and the remaining provisions of this Agreement shall remain in full force and effect and shall not be affected by the illegal, invalid or unenforceable provision or by its severance from this Agreement. Furthermore, in lieu of such illegal, invalid or unenforceable provision there shall be added automatically as part of this Agreement a provision as similar in terms to such illegal, invalid or unenforceable provision as may be possible and be legal, valid and enforceable.

(l)Withholding.  The Company shall be entitled to withhold from any amounts payable under this Agreement any federal, state, local or foreign withholding or other taxes or

charges which the Company is required to withhold. The Company shall be entitled to rely on an opinion of counsel if any questions as to the amount or requirement of withholding shall arise.

(m)Section 409A.

(i)General.  The intent of the Parties is that the payments and benefits under this Agreement comply with or be exempt from Section 409A of the Internal Revenue Code of 1986, as amended, and the regulations and guidance promulgated thereunder (collectively, “Section 409A”) and, accordingly, to the maximum extent permitted, this Agreement shall be interpreted to be in compliance therewith.  If Executive notifies the Company that Executive has received advice of tax counsel of a national reputation with expertise in Section 409A that any provision of this Agreement would cause Executive to incur any additional tax or interest under Section 409A (with specificity as to the reason therefor) or the Company independently makes such determination, the Company and Executive shall take commercially reasonable efforts to reform such provision to try to comply with or be exempt from Section 409A through good faith modifications to the minimum extent reasonably appropriate to conform with Section 409A, provided that any such modifications shall not increase the cost or liability to the Company.  To the extent that any provision hereof is modified in order to comply with or be exempt from Section 409A, such modification shall be made in good faith and shall, to the maximum extent reasonably possible, maintain the original intent and economic benefit to Executive and the Company of the applicable provision without violating the provisions of Section 409A.

(ii)Separation from Service.  Notwithstanding anything in this Agreement to the contrary, any compensation or benefits payable under this Agreement that is designated under this Agreement as payable upon Executive’s termination of employment shall be payable only upon Executive’s “separation from service” with the Company within the meaning of Section 409A (a “Separation from Service”) and, except as provided below, any such compensation or benefits shall not be paid, or, in the case of installments, shall not commence payment, until the thirtieth (30th) day following Executive’s Separation from Service.  Any installment payments that would have been made to Executive during the thirty (30) day period immediately following Executive’s Separation from Service but for the preceding sentence shall be paid to Executive on the thirtieth (30th) day following Executive’s Separation from Service and the remaining payments shall be made as provided in this Agreement.

(iii)Specified Employee.  Notwithstanding anything in this Agreement to the contrary, if Executive is deemed by the Company at the time of Executive’s Separation from Service to be a “specified employee” for purposes of Section 409A, to the extent delayed commencement of any portion of the benefits to which Executive is entitled under this Agreement is required in order to avoid a prohibited distribution under Section 409A, such portion of Executive’s benefits shall not be provided to Executive prior to the earlier of (i) the expiration of the six-month period measured from the date of Executive’s Separation from Service with the Company or (ii) the date of Executive’s death.  Upon the first business day following the expiration of the applicable Section 409A period, all payments deferred pursuant to the preceding sentence shall be paid in a lump sum to

Executive (or Executive’s estate or beneficiaries), and any remaining payments due to Executive under this Agreement shall be paid as otherwise provided herein.

(iv)Expense Reimbursements.  To the extent that any reimbursements under this Agreement are subject to Section 409A, any such reimbursements payable to Executive shall be paid to Executive no later than December 31 of the year following the year in which the expense was incurred; provided, that Executive submits Executive’s reimbursement request promptly following the date the expense is incurred, the amount of expenses reimbursed in one year shall not affect the amount eligible for reimbursement in any subsequent year, other than medical expenses referred to in Section 105(b) of the Code, and Executive’s right to reimbursement under this Agreement will not be subject to liquidation or exchange for another benefit.

(v)Installments.  Executive’s right to receive any installment payments under this Agreement, including without limitation any continuation salary payments that are payable on Company payroll dates, shall be treated as a right to receive a series of separate payments and, accordingly, each such installment payment shall at all times be considered a separate and distinct payment as permitted under Section 409A.  Except as otherwise permitted under Section 409A, no payment hereunder shall be accelerated or deferred unless such acceleration or deferral would not result in additional tax or interest pursuant to Section 409A.

12.Indemnification.

During and after the Term, the Company shall maintain and provide Executive with customary directors’ and officers’ insurance, and shall indemnify Executive and his legal representatives to the fullest extent permitted by law and the By-Laws of the Company as in effect on the date hereof, against all damages, costs, expenses and other liabilities incurred or sustained by Executive or his legal representatives in connection with any suit, action or proceeding to which Executive or his legal representatives may be made a party by reason of Executive being or having been a director or officer of the Company or any affiliate of the Company, or having served in any other capacity or taken any other action purportedly on behalf of or at the request of the Company or any affiliate of the Company.  During and after the Term and without the need for further approval by the Company’s Board of Directors, the Company will promptly advance or pay any and all amounts for costs or expenses (including but not limited to legal fees and expenses reasonably incurred by counsel of Executive’s choice retained by Executive) for which Executive may claim the Company is obligated to indemnify him.  Executive undertakes to repay such amounts if it is ultimately determined that he is not entitled to be indemnified by the Company as provided in this Section 12.

13.Employee Acknowledgement.

Executive acknowledges that Executive has read and understands this Agreement, is fully aware of its legal effect, has not acted in reliance upon any representations or promises made by the Company other than those contained in writing herein, and has entered into this Agreement freely based on Executive’s own judgment.

[Signature Page Follows]

IN WITNESS WHEREOF, the Parties have executed this Agreement on the date and year first above written.

COMPANY
By:
	Name:
	Title:
EXECUTIVE
By:

[Signature Page to Robert C. Reeves Employment Agreement]

EXHIBIT A

Form of Release

This Agreement and Release (“Agreement”) is made by and between Robert C. Reeves (“Executive”) and Athlon Holdings LP (the “Company”) (collectively, referred to as the “Parties” or individually referred to as a “Party”).  Capitalized terms used but not defined in this Agreement shall have the meanings set forth in the Employment Agreement (as defined below).

WHEREAS, the Parties have previously entered into that certain Employment Agreement, dated as of              , 2013 (the “Employment Agreement”); and

WHEREAS, in connection with the Employee’s termination of employment with the Company or a subsidiary or affiliate of the Company effective                 , 20    , the Parties wish to resolve any and all disputes, claims, complaints, grievances, charges, actions, petitions, and demands that the Employee may have against the Company and any of the Releasees as defined below arising out of or in any way related to Employee’s employment with or separation from the Company or its subsidiaries or affiliates.

NOW, THEREFORE, in consideration of the Severance Payments described in Section 4 of the Employment Agreement, which, pursuant to the Employment Agreement, are conditioned on the Employee’s execution and non-revocation of this Agreement, and in consideration of the mutual promises made herein, the Company and Employee hereby agree as follows:

1.Severance Payments; Salary and Benefits.  The Company agrees to provide Employee with the severance payments and benefits described in Section        of the Employment Agreement, payable at the times set forth in, and subject to the terms and conditions of, the Employment Agreement. In addition, to the extent not already paid, and subject to the terms and conditions of the Employment Agreement, the Company shall pay or provide to the Employee all other payments or benefits described in Section 3(c) of the Employment Agreement, subject to and in accordance with the terms thereof.

2.Release of Claims.  Employee, on his own behalf and on behalf of any of Employee’s affiliated companies or entities and any of their respective heirs, family members, executors, agents, and assigns, hereby and forever releases the Company, any of their direct or indirect subsidiaries and affiliates (including, without limitation,                                                    and their respective affiliated entities), and any of their current and former officers, directors, equity holders, managers, employees, agents, investors, attorneys, shareholders, administrators, affiliates, benefit plans, plan administrators, insurers, trustees, divisions, and subsidiaries and predecessor and successor corporations and assigns (collectively, the “Releasees”) from, and agrees not to sue concerning, or in any manner to institute, prosecute, or pursue, any claim, complaint, charge, duty, obligation, or cause of action relating to any matters of any kind, whether presently known or unknown, suspected or unsuspected, that Employee may possess against any of the Releasees arising from any omissions, acts, facts, or damages that have occurred up until and including the Effective Date of this Agreement (as defined in Section 8 below) arising out of or in any way related to Employee’s employment with or separation from the Company or its subsidiaries or affiliates, including, without limitation:

(a)any and all claims relating to or arising from Employee’s employment  or service relationship with the Company or any of its direct or indirect subsidiaries or affiliates and the termination of that relationship;

(b)any and all claims relating to, or arising from, Employee’s right to purchase, or actual purchase of any shares of stock or other equity interests of the Company or any of its affiliates, including, without limitation, any claims for fraud, misrepresentation, breach of fiduciary duty, breach of duty under applicable state corporate law, and securities fraud under any state or federal law;

(c)any and all claims for wrongful discharge of employment; termination in violation of public policy; discrimination; harassment; retaliation; breach of contract, both express and implied; breach of covenant of good faith and fair dealing, both express and implied; promissory estoppel; negligent or intentional infliction of emotional distress; fraud; negligent or intentional misrepresentation; negligent or intentional interference with contract or prospective economic advantage; unfair business practices; defamation; libel; slander; negligence; personal injury; assault; battery; invasion of privacy; false imprisonment; conversion; and disability benefits;

(d)any and all claims for violation of any federal, state, or municipal statute, including, but not limited to, Title VII of the Civil Rights Act of 1964; the Civil Rights Act of 1991; the Rehabilitation Act of 1973; the Americans with Disabilities Act of 1990; the Equal Pay Act; the Fair Labor Standards Act; the Fair Credit Reporting Act; the Age Discrimination in Employment Act of 1967; the Older Workers Benefit Protection Act; the Employee Retirement Income Security Act of 1974; the Worker Adjustment and Retraining Notification Act; the Family and Medical Leave Act; the Sarbanes-Oxley Act of 2002;

(e)any and all claims for violation of the federal or any state constitution;

(f)any and all claims arising out of any other laws and regulations relating to employment or employment discrimination;

(g)any claim for any loss, cost, damage, or expense arising out of any dispute over the non-withholding or other tax treatment of any of the proceeds received by Employee as a result of this Agreement; and

(h)any and all claims for attorneys’ fees and costs.

Employee agrees that the release set forth in this section shall be and remain in effect in all respects as a complete general release as to the matters released.  This release does not release claims that cannot be released as a matter of law, including, but not limited to, Employee’s right to file a charge with or participate in a charge by the Equal Employment Opportunity Commission, or any other local, state, or federal administrative body or government agency that is authorized to enforce or administer laws related to employment, against the Company (with the understanding that Employee’s release of claims herein bars Employee from recovering such monetary relief from the Company or any Releasee), claims for unemployment compensation or any state disability insurance benefits pursuant to the terms of applicable state law, claims to continued participation in certain of the Company’s group benefit plans pursuant to the terms and

conditions of COBRA, claims to any benefit entitlements vested as the date of separation of Employee’s employment, pursuant to written terms of any employee benefit plan of the Company or its affiliates and Employee’s right under applicable law and the Company’s D&O policy to seek indemnity for acts committed, or omissions, within the course and scope of the Employee’s employment duties.

3.Acknowledgment of Waiver of Claims under ADEA.  Employee understands and acknowledges that he is waiving and releasing any rights he may have under the Age Discrimination in Employment Act of 1967 (“ADEA”), and that this waiver and release is knowing and voluntary.  Employee understands and agrees that this waiver and release does not apply to any rights or claims that may arise under the ADEA after the Effective Date of this Agreement.  Employee understands and acknowledges that the consideration given for this waiver and release is in addition to anything of value to which Employee was already entitled.  Employee further understands and acknowledges that he has been advised by this writing that:  (a) he should consult with an attorney prior to executing this Agreement; (b) he has 21 days within which to consider this Agreement; (c) he has 7 days following his execution of this Agreement to revoke this Agreement; (d) this Agreement shall not be effective until after the revocation period has expired; and (e) nothing in this Agreement prevents or precludes Employee from challenging or seeking a determination in good faith of the validity of this waiver under the ADEA, nor does it impose any condition precedent, penalties, or costs for doing so, unless specifically authorized by federal law.  In the event Employee signs this Agreement and returns it to the Company in less than the 21 day period identified above, Employee hereby acknowledges that he has freely and voluntarily chosen to waive the time period allotted for considering this Agreement.

4.Severability.  In the event that any provision or any portion of any provision hereof or any surviving agreement made a part hereof becomes or is declared by a court of competent jurisdiction or arbitrator to be illegal, unenforceable, or void, this Agreement shall continue in full force and effect without said provision or portion of provision.

5.No Oral Modification.  This Agreement may only be amended in a writing signed by Employee and a duly authorized officer of the Company.

6.Governing Law; Dispute Resolution.  This Agreement shall be subject to the provisions of Sections 11(b) and 11(j) of the Employment Agreement.

7.Effective Date.  If the Employee has attained or is over the age of 40 as of the date of Employee’s termination of employment, then each Party has seven days after that Party signs this Agreement to revoke it and this Agreement will become effective on the eighth day after Employee signed this Agreement, so long as it has been signed by the Parties and has not been revoked by either Party before that date.

8.Voluntary Execution of Agreement.  Employee understands and agrees that he executed this Agreement voluntarily, without any duress or undue influence on the part or behalf of the Company or any third party, with the full intent of releasing all of his claims against the Company and any of the other Releasees.  Employee acknowledges that:  (a) he has read this Agreement; (b) he has not relied upon any representations or statements made by the Company

that are not specifically set forth in this Agreement; (c) he has been represented in the preparation, negotiation, and execution of this Agreement by legal counsel of his own choice or has elected not to retain legal counsel; (d) he understands the terms and consequences of this Agreement and of the releases it contains; and (e) he is fully aware of the legal and binding effect of this Agreement.

9.The restrictive covenants contained in Sections 5-8 of the Employment Agreement remain in effect and are not superseded or modified by this Release.

IN WITNESS WHEREOF, the Parties have executed this Agreement on the respective dates set forth below.

Dated:
	Robert C. Reeves
	ATHLON HOLDINGS LP
Dated:	By:
		Name:
		Title:

EX-10.4

Exhibit 10.4

Employment Agreement

This Employment Agreement (the “Agreement”), dated as of           , 2013 (the “Effective Date”), is made by and between Athlon Holdings LP, a Delaware limited partnership (together with any successor thereto, the “Company”), and              (the “Employee”) (collectively referred to herein as the “Parties”).

RECITALS

A.It is the desire of the Company to assure itself of the services of the Employee to the Company beginning upon the Effective Date by entering into this Agreement.

B.Employee and the Company mutually desire that Employee provide services to the Company on the terms herein provided.

AGREEMENT

NOW, THEREFORE, in consideration of the foregoing and of the respective covenants and agreements set forth below, the Parties hereto agree as follows:

1.Employment.

(a)General.  The Company shall employ Employee and Employee shall enter the employ of the Company, for the period and with the duties set forth in this Section 1, and upon the other terms and conditions herein provided.

(b)Employment Term.  The term of employment under this Agreement (the “Term”) shall be for the period beginning on the Effective Date, and ending on the second anniversary thereof, subject to earlier termination as provided in Section 3.  The Term shall automatically renew for additional one (1) year periods unless no later than ninety (90) days prior to the end of the otherwise applicable Term either party gives written notice of non-renewal (“Notice of Non-Renewal”) to the other, in which case Employee’s employment will terminate at the end of the then-applicable Term or any other date set by the Company in accordance with Section 3 and subject to earlier termination as provided in Section 3.

(c)Duties.  Employee shall devote all of Employee’s working time and efforts to the business and affairs of the Company (which shall include service to its affiliates, if applicable), provided that Employee shall be permitted to (i) manage Employee’s personal, financial and legal affairs, (ii) participate in trade associations, and (iii) serve on the board of directors of not-for-profit or tax-exempt charitable organizations, in each case, subject to compliance with this Agreement and provided that such activities do not materially interfere with Employee’s performance of Employee’s duties and responsibilities hereunder.  Employee shall perform the duties and responsibilities normally associated with the position of                         and as may from time to time be assigned to him by the Chief Executive Officer of the Company or his designee.  Employee agrees to observe and comply with the rules and policies of the Company as adopted by the Company from time to time.  Employee represents and covenants to the Company that he is not subject or a party to any employment agreement, non-competition covenant,

nondisclosure agreement, or any similar agreement, covenant, understanding, or restriction that would prohibit Employee from executing this Agreement and fully performing his duties and responsibilities hereunder, or would in any manner, directly or indirectly, limit or affect the duties and responsibilities that may now or in the future be assigned to Employee hereunder.

2.Compensation and Related Matters.

(a)Annual Base Salary.  During the Term, Employee shall receive a base salary at a rate of $             per annum (the “Annual Base Salary”), which shall be paid in accordance with the customary payroll practices of the Company.  Such Annual Base Salary shall be reviewed (and may be adjusted) from time to time by the Board of Supervisors (the “Board”) or an authorized committee of the Board, provided that such Annual Base Salary shall not be reduced for two years after the Effective Date.

(b)Bonus and Equity Compensation.  During the Term, the Employee will be eligible to participate in an incentive program and an equity incentive plan established by the Board.  The bonus awards payable under the incentive program shall be based on the achievement of performance goals to be determined by the Board or its designee.

(c)Benefits.  During the Term, Employee may participate in such employee benefit plans and programs as the Company may from time to time offer to provide to its employees, pursuant to the terms and eligibility requirements of those plans, provided, however, Employee shall not be eligible to participate in a Company plan that provides medical, dental or life insurance benefits to the extent such Company plan is substantially comparable to one of the plans sponsored by Employee’s previous employer that Employee participates in as of the Effective Date, unless and until Employee ceases to participate in such substantially comparable plan of his previous employer.

(d)Vacation.  During the Term, Employee shall be entitled to paid vacation in accordance with the Company’s vacation policy, as it may be amended from time to time.  Any vacation shall be taken at the reasonable and mutual convenience of the Company and Employee.

(e)Expenses.  During the Term, the Company shall reimburse Employee for all reasonable travel and other business expenses incurred by Employee in the performance of Employee’s duties to the Company in accordance with the Company’s expense reimbursement policy.

(f)Key Person Insurance.  At any time during the Term, the Company shall have the right to insure the life of Employee for the Company’s sole benefit.  The Company shall have the right to determine the amount of insurance and the type of policy.  Employee shall reasonably cooperate with the Company in obtaining such insurance by submitting to physical examinations, by supplying all information reasonably required by any insurance carrier, and by executing all necessary documents reasonably required by any insurance carrier.

2

3.Termination.

Employee’s employment hereunder may be terminated by the Company or Employee, as applicable, without any breach of this Agreement under the following circumstances:

(a)Circumstances.

(i)Death.  Employee’s employment hereunder shall terminate upon Employee’s death.

(ii)Disability.  If Employee has incurred a Disability, as defined below, the Company may terminate Employee’s employment.

(iii)Termination for Cause.  The Company may terminate Employee’s employment for Cause, as defined below.

(iv)Termination without Cause.  The Company may terminate Employee’s employment without Cause.

(v)Resignation from the Company for Good Reason.  Employee may resign Employee’s employment with the Company for Good Reason, as defined below.

(vi)Resignation from the Company Without Good Reason.  Employee may resign Employee’s employment with the Company for any reason other than Good Reason or for no reason.

(vii)Non-extension of Term by the Company.  The Company may give notice of non-extension to Employee pursuant to Section 1.

(viii)Non-extension of Term by Employee.  Employee may give notice of non-extension to the Company pursuant to Section 1.

(b)Notice of Termination.  Any termination of Employee’s employment by the Company or by Employee under this Section 3 (other than termination pursuant to paragraph (a)(i)) shall be communicated by a written notice to the other party hereto (i) indicating the specific termination provision in this Agreement relied upon, (ii) setting forth in reasonable detail the facts and circumstances claimed to provide a basis for termination of Employee’s employment under the provision so indicated, and (iii) specifying a Date of Termination which, if submitted by Employee, shall be at least thirty (30) days following the date of such notice (a “Notice of Termination”); provided, however, that in the event that Employee delivers a Notice of Termination to the Company, the Company may, in its sole discretion, change the Date of Termination to any date that occurs following the date of Company’s receipt of such Notice of Termination and is prior to the date specified in such Notice of Termination.  A Notice of Termination submitted by the Company may provide for a Date of Termination on the date Employee receives the Notice of Termination, or any date thereafter elected by the Company in its sole discretion.  The failure by the Company to set forth in the Notice of Termination any fact or circumstance which contributes to a showing of Cause shall not waive any right of the

3

Company hereunder or preclude the Company from asserting such fact or circumstance in enforcing the Company’s rights hereunder.

(c)Company Obligations upon Termination.  Upon termination of Employee’s employment pursuant to any of the circumstances listed in Section 3, Employee (or Employee’s estate) shall be entitled to receive the sum of:  (i) the portion of Employee’s Annual Base Salary earned through the Date of Termination, but not yet paid to Employee, plus any accrued vacation earned through the Date of Termination, but not used by Employee; (ii) any expenses owed to Employee pursuant to Section 2(e); and (iii) any amount accrued and arising from Employee’s participation in, or benefits accrued under any employee benefit plans, programs or arrangements, which amounts shall be payable in accordance with the terms and conditions of such employee benefit plans, programs or arrangements (collectively, the “Company Arrangements”).  Except as otherwise expressly required by law (e.g., COBRA) or as specifically provided herein, all of Employee’s rights to salary, severance, benefits, bonuses and other amounts hereunder (if any) shall cease upon the termination of Employee’s employment hereunder.  In the event that Employee’s employment is terminated by the Company for any reason, Employee’s sole and exclusive remedy shall be to receive the severance payments and benefits described in this Section 3(c) or Section 4, as applicable.

(d)Deemed Resignation.  Upon termination of Employee’s employment for any reason, Employee shall be deemed to have resigned from all offices and directorships, if any, then held with the Company or any of its affiliates.

4.Severance Payments.

(a)Termination for Cause, or Termination Upon Death, Disability, Resignation from the Company Without Good Reason, Non-extension of Term by Employee or Company.  If Employee’s employment shall terminate as a result of Employee’s death pursuant to Section 3(a)(i) or Disability pursuant to Section 3(a)(ii), pursuant to Section 3(a)(iii) for Cause, pursuant to Section 3(a)(vi) for Employee’s resignation from the Company without Good Reason, or for no reason, pursuant to Section 3(a)(vii) or (viii) due to non-extension of the Term by Employee or the Company, Employee shall not be entitled to any severance payments or benefits, except as provided in Section 3(c).

(b)Termination without Cause or Resignation with Good Reason.

(i)If Employee’s employment shall terminate without Cause pursuant to Section 3(a)(iv) or pursuant to Section 3(a)(v) due to Employee’s resignation for Good Reason, then, subject to Employee signing on or before the 45th day following Employee’s Separation from Service (as defined below), and not revoking, a release of claims in the form attached as Exhibit A to this Agreement (the “Release”), and Employee’s continued compliance with Sections 5 and 6, Employee shall receive, in addition to payments and benefits set forth in Section 3(c), the following:

(A)an amount in cash equal to one (1) times the Annual Base Salary of Employee as of the Date of Termination (without regard to any reduction that triggers a termination for Good Reason), payable in the

4

form of salary continuation in regular installments over the twelve (12) month period following the date of Employee’s Separation from Service (the “Severance Period”) in accordance with the Company’s normal payroll practices; and

(B)if Employee elects to receive continued healthcare coverage pursuant to the Consolidated Omnibus Budget Reconciliation Act of 1985, as amended (“COBRA”), the Company shall directly pay, or reimburse Employee for, the COBRA premiums for Employee and Employee’s covered dependents during the period commencing on Employee’s Separation from Service and ending upon the earliest of (X) the last day of the Severance Period, (Y) the date that Employee and/or Employee’s covered dependents become no longer eligible for COBRA or (Z) the date Employee becomes eligible to receive substantially comparable healthcare coverage from a subsequent employer.

In the event Employee fails to sign the Release within 45 days, or revokes the Release, then Employee will not be entitled to receive the additional consideration in subparts (i) and (ii).

(c)Change in Control.  Notwithstanding anything to the contrary in Section 4(b), in the event Employee’s employment terminates without Cause pursuant to Section 3(a)(iv), or pursuant to Section 3(a)(vi) due to non-extension of the Term by the Company, in either case within one year following the date of a Change in Control: (i) with respect to Section 4(b)(i), in lieu of the amount specified therein, Employee shall be entitled to receive an amount in cash equal to two and one-half (2.5) times the Annual Base Salary, plus two and one-half (2.5) times the greater of the average of the Employee’s previous two years’ annual bonus payments or the Target Bonus, which cash payment shall be paid in a single lump sum within 30 days after the Employee’s Separation from Service if the Change in Control also constitutes a “change in control event” within the meaning of Treasury Regulation Section 1.409A-3(i)(5); and (ii) with respect to Section 4(b)(ii), Company shall continue to pay or reimburse Employee’s healthcare coverage for up to eighteen (18) months, subject to Section 4(b)(i)(B)(Y)-(Z).

(d)Survival.  Notwithstanding anything to the contrary in this Agreement, the provisions of Sections 5 through 9 and Section 11 will survive the termination of Employee’s employment and the expiration or termination of the Term.

5.Competition.  Employee acknowledges that the Company has provided and the Company agrees to continue to provide Employee with access to its confidential, proprietary, and/or trade secret information, including confidential information of third parties such as customers, suppliers, and business affiliates; specialized training and knowledge regarding the Company’s methodologies and business strategies; and/or support in the development of goodwill such as introductions and customer relationship information. The foregoing is not contingent on continued employment, but upon Employee’s use of the access, specialized training, and/or goodwill support provided by Company for the exclusive benefit of the Company and upon Employee’s full compliance with the restrictions on Employee’s conduct provided for in this Agreement.  Ancillary to the rights provided to Employee as set forth in this Agreement, the Company’s provision of confidential, proprietary, and/or trade secret

5

information, specialized training, and/or goodwill support to Employee, and Employee’s agreements regarding the use of same, in order to protect the value of any equity-based compensation, training, goodwill support and/or the confidential information described above, the Company and Employee agree to the following provisions against unfair competition, which Employee acknowledges represent a fair balance of the Company’s rights to protect its business and Employee’s right to pursue employment:

(a)Employee shall not, at any time during the Restriction Period, directly or indirectly engage in, have any equity interest in, interview for a potential employment or consulting relationship with or manage or operate any person, firm, corporation, partnership or business (whether as director, officer, employee, agent, representative, partner, security holder, consultant or otherwise) that engages in any business which competes with any portion of the Business (as defined below) of the Company in the United States; provided, however, in the event the Company terminates Employee’s employment without Cause or the Employee resigns for Good Reason, the post-termination restrictions set forth in this Section 5(a) shall be limited to the following: (a) Employee shall not, at any time during the Restriction Period following the Date of Termination, directly or indirectly engage in, have any equity interest in, interview for a potential employment or consulting relationship with or manage or operate any person, firm, corporation, partnership or business (whether as director, officer, employee, agent, representative, partner, security holder, consultant or otherwise) that engages in any business which competes in any material respect with any material portion of the Business (as defined below) of the Company within fifty (50) miles of (i) any oil or natural gas assets of the Company or (ii) any potential oil or natural gas assets where the Company has taken material steps to lease or purchase real property with respect to such potential assets within the six (6) month period immediately prior to the Date of Termination; provided, that the Company provides Employee with a written list of any such potential leases or real property within five (5) days following the Date of Termination.  Nothing herein shall prohibit Employee from being a passive owner of not more than 2% of the outstanding equity interest in any entity that is publicly traded, so long as Employee has no active participation in the business of such entity.

(b)Employee shall not, at any time during the Restriction Period, directly or indirectly, recruit or otherwise solicit or induce any employee, customer, subscriber or supplier of the Company (i) to terminate its employment or arrangement with the Company, or (ii) to otherwise change its relationship with the Company. Employee shall not, at any time during the Restriction Period, directly or indirectly, either for Employee or for any other person or entity, (x) solicit any employee of the Company to terminate his or her employment with the Company, (y) employ any such individual during his or her employment with the Company and for a period of six months after such individual terminates his or her employment with the Company or (z) solicit or service any person who was a customer, supplier, licensee, licensor or other business relation of the Company in order to induce or attempt to induce such person to cease doing business with, or reduce the amount of business conducted with, the Company, or in any way interfere with the relationship between any such customer, supplier, licensee, licensor or other business relation of the Company.

(c)In the event the terms of this Section 5 shall be determined by any court of competent jurisdiction to be unenforceable by reason of its extending for too great a period of time or over too great a geographical area or by reason of its being too extensive in any other

6

respect, it will be interpreted to, and may be modified by a court of competent jurisdiction to, extend only over the maximum period of time for which it may be enforceable, over the maximum geographical area as to which it may be enforceable, or to the maximum extent in all other respects as to which it may be enforceable, all as determined by such court in such action.

(d)As used in this Section 5, (i) the term “Company” shall include the Company and its direct and indirect parents and subsidiaries, (ii) the term “Business” shall mean the business of the Company and shall include the acquisition, exploration, exploitation and development of, oil and natural gas assets, and the acquisition of leases and other real property in connection therewith, as such business may be expanded or altered by the Company during the Term; and (iii) the term “Restriction Period” shall mean the period beginning on the Effective Date and ending on the date twelve (12) months following the Date of Termination, except that if Employee’s termination of employment occurs within one year following a Change in Control, Restriction Period shall mean the period beginning on the Effective Date and ending on the date six (6) months following the Date of Termination.

(e)Employee agrees, during the Term and following the Date of Termination, to refrain from disparaging the Company and its affiliates, including any of its services, technologies or practices, or any of its directors, officers, agents, representatives or stockholders, either orally or in writing.  Nothing in this paragraph shall preclude Employee from making truthful statements that are reasonably necessary to comply with applicable law, regulation or legal process.

(f)Company agrees, during the Term and following the Date of Termination, to refrain from disparaging the Employee, including any of Employee’s services or practices, either orally or in writing.  Nothing in this paragraph shall preclude Company from making truthful statements that are reasonably necessary to comply with applicable law, regulation or legal process.

(g)Employee represents that Employee’s employment by the Company does not and will not breach any agreement with any former employer, including any non-compete agreement or any agreement to keep in confidence or refrain from using information acquired by Employee prior to Employee’s employment by the Company.  During Employee’s employment by the Company, Employee agrees that Employee will not violate any non-solicitation agreements Employee entered into with any former employer or improperly make use of, or disclose, any information or trade secrets of any former employer or other third party, nor will Employee bring onto the premises of the Company or use any unpublished documents or any property belonging to any former employer or other third party, in violation of any lawful agreements with that former employer or third party.

(h)Tolling.  In the event Employee engages in conduct in violation of his covenants in Sections 5(a) or (b), the Restriction Period shall be extended for a period of time equal to the time in which Employee engaged in competitive activity prohibited by this Agreement.

7

6.Nondisclosure of Proprietary Information.

(a)Except in connection with the faithful performance of Employee’s duties hereunder or pursuant to Section 6(c) and (e), Employee shall, in perpetuity, maintain in confidence and shall not directly, indirectly or otherwise, use, disseminate, disclose or publish, or use for Employee’s benefit or the benefit of any person, firm, corporation or other entity any confidential or proprietary information or trade secrets of or relating to the Company (including, without limitation, business plans, business strategies and methods, acquisition targets, intellectual property in the form of patents, trademarks and copyrights and applications therefor, ideas, inventions, works, discoveries, improvements, information, documents, formulae, practices, processes, methods, developments, source code, modifications, technology, techniques, data, programs, other know-how or materials, owned, developed or possessed by the Company, whether in tangible or intangible form, information with respect to the Company’s operations, processes, products, inventions, business practices, finances, principals, vendors, suppliers, customers, potential customers, marketing methods, costs, prices, contractual relationships, regulatory status, prospects and compensation paid to employees or other terms of employment) (collectively, the “Confidential Information”), or deliver to any person, firm, corporation or other entity any document, record, notebook, computer program or similar repository of or containing any such Confidential Information.  The Parties hereby stipulate and agree that, as between them, any item of Confidential Information is important, material and confidential and affects the successful conduct of the businesses of the Company (and any successor or assignee of the Company).  Notwithstanding the foregoing, Confidential Information shall not include any information that has been published in a form generally available to the public prior to the date Employee proposes to disclose or use such information, provided, that such publishing of the Confidential Information shall not have resulted from Employee directly or indirectly breaching Employee’s obligations under this Section 6(a) or any other similar provision by which Employee is bound, or from any third-party breaching a provision similar to that found under this Section 6(a).  For the purposes of the previous sentence, Confidential Information will not be deemed to have been published or otherwise disclosed merely because individual portions of the information have been separately published, but only if all material features comprising such information have been published in combination.

(b)Upon termination of Employee’s employment with the Company for any reason, Employee will promptly deliver to the Company all correspondence, drawings, manuals, letters, notes, notebooks, reports, programs, plans, proposals, financial documents, or any other documents or property concerning the Company’s customers, business plans, marketing strategies, products, property or processes.

(c)Employee may respond to a lawful and valid subpoena or other legal process but shall give the Company the earliest possible notice thereof, shall, as much in advance of the return date as possible, make available to the Company and its counsel the documents and other information sought and shall assist such counsel at Company’s expense in resisting or otherwise responding to such process.

(d)As used in this Section 6 and Section 7, the term “Company” shall include the Company and its direct and indirect parents and subsidiaries.

8

(e)Nothing in this Agreement shall prohibit Employee from (i) disclosing information and documents when required by law, subpoena or court order (subject to the requirements of Section 6(c) above), (ii) disclosing information and documents to Employee’s attorney or tax adviser for the purpose of securing legal or tax advice, (iii) disclosing Employee’s post-employment restrictions in this Agreement in confidence to any potential new employer, or (iv) retaining, at any time, Employee’s personal correspondence, Employee’s personal contacts and documents related to Employee’s own personal benefits, entitlements and obligations.

7.Inventions.

All rights to discoveries, inventions, improvements and innovations (including all data and records pertaining thereto) related to the business of the Company, whether or not patentable, copyrightable, registrable as a trademark, or reduced to writing, that Employee may discover, invent or originate during the Term, either alone or with others and whether or not during working hours or by the use of the facilities of the Company (“Inventions”), shall be the exclusive property of the Company.  Employee shall promptly disclose all Inventions to the Company, shall execute at the request of the Company any assignments or other documents the Company may deem reasonably necessary to protect or perfect its rights therein, and shall assist the Company, upon reasonable request and at the Company’s expense, in obtaining, defending and enforcing the Company’s rights therein. Employee hereby appoints the Company as Employee’s attorney-in-fact to execute on Employee’s behalf any assignments or other documents reasonably deemed necessary by the Company to protect or perfect its rights to any Inventions.

8.Injunctive Relief.

It is recognized and acknowledged by Employee that a breach of the covenants contained in Sections 5, 6 and 7 will cause irreparable damage to Company and its goodwill, the exact amount of which will be difficult or impossible to ascertain, and that the remedies at law for any such breach will be inadequate.  Accordingly, Employee agrees that in the event of a breach of any of the covenants contained in Sections 5, 6 and 7, in addition to any other remedy which may be available at law or in equity, the Company will be entitled to specific performance and injunctive relief without the need to post bond.

9.Assignment and Successors.

The Company may assign its rights and obligations under this Agreement to any successor to all or substantially all of the business or the assets of the Company (by merger or otherwise), and may assign or encumber this Agreement and its rights hereunder as security for indebtedness of the Company and its affiliates.  This Agreement shall be binding upon and inure to the benefit of the Company, Employee and their respective successors, assigns, personnel and legal representatives, executors, administrators, heirs, distributees, devisees, and legatees, as applicable.  None of Employee’s rights or obligations may be assigned or transferred by Employee, other than Employee’s rights to payments hereunder, which may be transferred only by will or operation of law.  Notwithstanding the foregoing, Employee shall be entitled, to the extent permitted under applicable law and applicable Company Arrangements, to select and

9

change a beneficiary or beneficiaries to receive compensation hereunder following Employee’s death by giving written notice thereof to the Company.

10.Certain Definitions.

(a)Cause.  The Company shall have “Cause” to terminate Employee’s employment hereunder upon:

(i)the Board’s determination that Employee failed to substantially perform Employee’s duties as an employee of the Company (other than any such failure resulting from Employee’s Disability);

(ii)the Board’s determination that Employee failed in any material respect to carry out or comply with any lawful and reasonable directive of the Board consistent with the terms of this Agreement;

(iii)Employee’s material breach of this Agreement;

(iv)Employee’s conviction, plea of no contest, plea of nolo contendere, or imposition of unadjudicated probation for any felony or crime involving moral turpitude;

(v)Employee’s unlawful use (including being under the influence) or possession of illegal drugs on the Company’s (or any of its affiliate’s) premises or while performing Employee’s duties and responsibilities under this Agreement; or

(vi)Employee’s commission of an act of fraud, embezzlement, misappropriation, willful misconduct, or breach of fiduciary duty against the Company or any of its affiliates.

(b)Change in Control.  “Change in Control” shall be as defined in the Athlon Energy Inc. 2013 Incentive Award Plan, without regard to any amendments to such plan that may be adopted after the date of Athlon Energy Inc.’s initial public offering.

(c)Date of Termination.  “Date of Termination” shall mean (i) if Employee’s employment is terminated by Employee’s death, the date of Employee’s death; (ii) if Employee’s employment is terminated pursuant to Section 3(a)(ii) – (v) either the date indicated in the Notice of Termination or the date specified by the Company pursuant to Section 3(b), whichever is earlier; (iii) if Employee’s employment is terminated pursuant to Section 3(a)(vi) or Section 3(a)(vii), the expiration of the then-applicable Term.

(d)Disability.  “Disability” shall mean, at any time the Company or any of its affiliates sponsors a long-term disability plan for the Company’s employees, “disability” as defined in such long-term disability plan for the purpose of determining a participant’s eligibility for benefits, provided, however, if the long-term disability plan contains multiple definitions of disability, “Disability” shall refer to that definition of disability which, if Employee qualified for such disability benefits, would provide coverage for the longest period of time. The determination of whether Employee has a Disability shall be made by the person or persons required to make disability determinations under the long-term disability plan.  At any time the

10

Company does not sponsor a long-term disability plan for its employees, Disability shall mean Employee’s inability to perform, with or without reasonable accommodation, the essential functions of Employee’s position with the Company for a total of three months during any six-month period as a result of incapacity due to mental or physical illness as determined by a physician selected by the Company or its insurers and acceptable to Employee or Employee’s legal representative, with such agreement as to acceptability not to be unreasonably withheld or delayed.  Any refusal by Employee to submit to a medical examination for the purpose of determining Disability shall be deemed to constitute conclusive evidence of Employee’s Disability.

(e)Good Reason.  “Good Reason” shall mean the occurrence of any of the following events without Employee’s express written consent:

(i)Any reduction in Employee’s Annual Base Salary, provided that Employee specifically terminates his employment for Good Reason hereunder within 90 days from the date that he has actual notice of any such reduction;

(ii)Any material breach by the Company of this Agreement, provided that Employee specifically terminates his employment for Good Reason hereunder within 90 days from the date that he has actual notice of such material breach;

(iii)Employee’s duties or responsibilities for the Company or its successor are materially reduced or there is any material change in Employee’s title or any material change in the types of positions reporting to Employee or the type of position to whom Employee reports, provided that Employee specifically terminates his employment for Good Reason hereunder within 90 days following his receipt of actual notice of such reduction or change; or

(iv)Any transfer of Employee’s primary place of employment of more than 50 miles from 777 Main Street, Fort Worth, Texas, provided that such transfer increases Employee’s commute by more than 50 miles, and provided, further, that Employee specifically terminates his employment for Good Reason hereunder within 90 days following such transfer.

In any case, if Employee desires to terminate his employment for Good Reason in accordance herewith, he shall first give written notice of the facts and circumstances providing the basis for Good Reason to the Board, and allow the Company 30 days from the date of such notice to remedy, cure or rectify the situation giving rise to Good Reason.

11.Miscellaneous Provisions.

(a)Governing Law.  This Agreement shall be governed, construed, interpreted and enforced in accordance with its express terms, and otherwise in accordance with the substantive laws of the State of Texas without reference to the principles of conflicts of law of the State of Texas or any other jurisdiction, and where applicable, the laws of the United States.

11

(b)Validity.  The invalidity or unenforceability of any provision or provisions of this Agreement shall not affect the validity or enforceability of any other provision of this Agreement, which shall remain in full force and effect.

(c)Notices.  Any notice, request, claim, demand, document and other communication hereunder to any Party shall be effective upon receipt (or refusal of receipt) and shall be in writing and delivered personally or sent by facsimile or certified or registered mail, postage prepaid, as follows:

(i)If to the Company:

420 Throckmorton Street, Suite 1200

Fort Worth, TX 76102

Attn:  Chief Executive Officer

(ii)If to Employee, at the last address that the Company has in its personnel records for Employee.

or at any other address as any Party shall have specified by notice in writing to the other Party.

(d)Counterparts.  This Agreement may be executed in several counterparts, each of which shall be deemed to be an original, but all of which together will constitute one and the same Agreement.  Signatures delivered by facsimile shall be deemed effective for all purposes.

(e)Entire Agreement.  The terms of this Agreement are intended by the Parties to be the final expression of their agreement with respect to the employment of Employee by the Company and supersede all prior understandings and agreements, whether written or oral, including any employment agreement previously entered into between Employee and Athlon Energy LP (“Prior Agreement”).  The Parties further intend that this Agreement shall constitute the complete and exclusive statement of their terms and that no extrinsic evidence whatsoever may be introduced in any judicial, administrative, or other legal proceeding to vary the terms of this Agreement.

(f)Amendments; Waivers.  This Agreement may not be modified, amended, or terminated except by an instrument in writing, signed by Employee and a duly authorized officer of Company.  By an instrument in writing similarly executed, Employee or a duly authorized officer of the Company, as applicable, may waive compliance by the other Party with any specifically identified provision of this Agreement that such other Party was or is obligated to comply with or perform; provided, however, that such waiver shall not operate as a waiver of, or estoppel with respect to, any other or subsequent failure.  No failure to exercise and no delay in exercising any right, remedy, or power hereunder preclude any other or further exercise of any other right, remedy, or power provided herein or by law or in equity.

(g)No Inconsistent Actions.  The Parties hereto shall not voluntarily undertake or fail to undertake any action or course of action inconsistent with the provisions or essential intent of this Agreement.  Furthermore, it is the intent of the Parties hereto to act in a fair and reasonable manner with respect to the interpretation and application of the provisions of this Agreement.

12

(h)Construction.  This Agreement shall be deemed drafted equally by both the Parties. Its language shall be construed as a whole and according to its fair meaning.  Any presumption or principle that the language is to be construed against any Party shall not apply.  The headings in this Agreement are only for convenience and are not intended to affect construction or interpretation.  Any references to paragraphs, subparagraphs, sections or subsections are to those parts of this Agreement, unless the context clearly indicates to the contrary.  Also, unless the context clearly indicates to the contrary, (a) the plural includes the singular and the singular includes the plural; (b) “and” and “or” are each used both conjunctively and disjunctively; (c) “any,” “all,” “each,” or “every” means “any and all,” and “each and every”; (d) “includes” and “including” are each “without limitation”; (e) “herein,” “hereof,” “hereunder” and other similar compounds of the word “here” refer to the entire Agreement and not to any particular paragraph, subparagraph, section or subsection; and (f) all pronouns and any variations thereof shall be deemed to refer to the masculine, feminine, neuter, singular or plural as the identity of the entities or persons referred to may require.

(i)Arbitration.  Any controversy, claim or dispute arising out of or relating to this Agreement, shall be settled solely and exclusively by a binding arbitration process for employment claims administered by JAMS/Endispute in Fort Worth, Texas.  Such arbitration shall be conducted in accordance with the then-existing JAMS/Endispute Rules of Practice and Procedure, with the following exceptions if in conflict: (a) one arbitrator who is a retired judge shall be chosen by JAMS/Endispute; (b) each Party to the arbitration will pay its pro rata share of the expenses and fees of the arbitrator, together with other expenses of the arbitration incurred or approved by the arbitrator; and (c) arbitration may proceed in the absence of any Party if written notice (pursuant to the JAMS/Endispute rules and regulations) of the proceedings has been given to such Party.  Each Party shall bear its own attorneys fees and expenses.  The Parties agree to abide by all decisions and awards rendered in such proceedings.  Such decisions and awards rendered by the arbitrator shall be final and conclusive.  All such controversies, claims or disputes shall be settled in this manner in lieu of any action at law or equity; provided, however, that nothing in this subsection shall be construed as precluding the bringing an action for injunctive relief or specific performance as provided in this Agreement.  This dispute resolution process and any arbitration hereunder shall be confidential and neither any Party nor the neutral arbitrator shall disclose the existence, contents or results of such process without the prior written consent of all Parties.  If JAMS/Endispute no longer exists or is otherwise unavailable, the Parties agree that the American Arbitration Association (“AAA’) shall administer the arbitration in accordance with its then-existing rules for employment claims.  In such event, all references herein to JAMS/Endispute shall mean AAA.  Notwithstanding the foregoing, Employee and the Company each have the right to resolve any issue or dispute over intellectual property rights by Court action instead of arbitration.

(j)Enforcement.  If any provision of this Agreement is held to be illegal, invalid or unenforceable under present or future laws effective during the term of this Agreement, such provision shall be fully severable; this Agreement shall be construed and enforced as if such illegal, invalid or unenforceable provision had never comprised a portion of this Agreement; and the remaining provisions of this Agreement shall remain in full force and effect and shall not be affected by the illegal, invalid or unenforceable provision or by its severance from this Agreement. Furthermore, in lieu of such illegal, invalid or unenforceable provision there shall be

13

added automatically as part of this Agreement a provision as similar in terms to such illegal, invalid or unenforceable provision as may be possible and be legal, valid and enforceable.

(k)Withholding.  The Company shall be entitled to withhold from any amounts payable under this Agreement any federal, state, local or foreign withholding or other taxes or charges which the Company is required to withhold. The Company shall be entitled to rely on an opinion of counsel if any questions as to the amount or requirement of withholding shall arise.

(l)Section 409A.

(i)General.  The intent of the Parties is that the payments and benefits under this Agreement comply with or be exempt from Section 409A of the Internal Revenue Code of 1986, as amended, and the regulations and guidance promulgated thereunder (collectively, “Section 409A”) and, accordingly, to the maximum extent permitted, this Agreement shall be interpreted to be in compliance therewith.  If Employee notifies the Company that Employee has received advice of tax counsel of a national reputation with expertise in Section 409A that any provision of this Agreement would cause Employee to incur any additional tax or interest under Section 409A (with specificity as to the reason therefor) or the Company independently makes such determination, the Company and Employee shall take commercially reasonable efforts to reform such provision to try to comply with or be exempt from Section 409A through good faith modifications to the minimum extent reasonably appropriate to conform with Section 409A, provided that any such modifications shall not increase the cost or liability to the Company.  To the extent that any provision hereof is modified in order to comply with or be exempt from Section 409A, such modification shall be made in good faith and shall, to the maximum extent reasonably possible, maintain the original intent and economic benefit to Employee and the Company of the applicable provision without violating the provisions of Section 409A.

(ii)Separation from Service.  Notwithstanding anything in this Agreement to the contrary, any compensation or benefits payable under this Agreement that is designated under this Agreement as payable upon Employee’s termination of employment shall be payable only upon Employee’s “separation from service” with the Company within the meaning of Section 409A (a “Separation from Service”) and, except as provided below, any such compensation or benefits shall not be paid, or, in the case of installments, shall not commence payment, until the thirtieth (30th) day following Employee’s Separation from Service.  Any installment payments that would have been made to Employee during the thirty (30) day period immediately following Employee’s Separation from Service but for the preceding sentence shall be paid to Employee on the thirtieth (30th) day following Employee’s Separation from Service and the remaining payments shall be made as provided in this Agreement..

(iii)Specified Employee.  Notwithstanding anything in this Agreement to the contrary, if Employee is deemed by the Company at the time of Employee’s Separation from Service to be a “specified employee” for purposes of Section 409A, to the extent delayed commencement of any portion of the benefits to which Employee is entitled under this Agreement is required in order to avoid a prohibited distribution under Section

14

409A, such portion of Employee’s benefits shall not be provided to Employee prior to the earlier of (i) the expiration of the six-month period measured from the date of Employee’s Separation from Service with the Company or (ii) the date of Employee’s death.  Upon the first business day following the expiration of the applicable Section 409A period, all payments deferred pursuant to the preceding sentence shall be paid in a lump sum to Employee (or Employee’s estate or beneficiaries), and any remaining payments due to Employee under this Agreement shall be paid as otherwise provided herein.

(iv)Expense Reimbursements.  To the extent that any reimbursements under this Agreement are subject to Section 409A, any such reimbursements payable to Employee shall be paid to Employee no later than December 31 of the year following the year in which the expense was incurred; provided, that Employee submits Employee’s reimbursement request promptly following the date the expense is incurred, the amount of expenses reimbursed in one year shall not affect the amount eligible for reimbursement in any subsequent year, other than medical expenses referred to in Section 105(b) of the Code, and Employee’s right to reimbursement under this Agreement will not be subject to liquidation or exchange for another benefit.

(v)Installments.  Employee’s right to receive any installment payments under this Agreement, including without limitation any continuation salary payments that are payable on Company payroll dates, shall be treated as a right to receive a series of separate payments and, accordingly, each such installment payment shall at all times be considered a separate and distinct payment as permitted under Section 409A.  Except as otherwise permitted under Section 409A, no payment hereunder shall be accelerated or deferred unless such acceleration or deferral would not result in additional tax or interest pursuant to Section 409A.

12.Indemnification.

During and after the Term, the Company shall maintain and provide Employee with customary directors’ and officers’ insurance, and shall indemnify Employee and his legal representatives to the fullest extent permitted by law and the By-Laws of the Company as in effect on the date hereof, against all damages, costs, expenses and other liabilities incurred or sustained by Employee or his legal representatives in connection with any suit, action or proceeding to which Employee or his legal representatives may be made a party by reason of Employee being or having been a director or officer of the Company or any affiliate of the Company, or having served in any other capacity or taken any other action purportedly on behalf of or at the request of the Company or any affiliate of the Company.  During and after the Term and without the need for further approval by the Company’s Board of Directors, the Company will promptly advance or pay any and all amounts for costs or expenses (including but not limited to legal fees and expenses reasonably incurred by counsel of Employee’s choice retained by Employee) for which Employee may claim the Company is obligated to indemnify him.  Employee undertakes to repay such amounts if it is ultimately determined that he is not entitled to be indemnified by the Company as provided in this Section 12.

15

13.Employee Acknowledgement.

Employee acknowledges that Employee has read and understands this Agreement, is fully aware of its legal effect, has not acted in reliance upon any representations or promises made by the Company other than those contained in writing herein, and has entered into this Agreement freely based on Employee’s own judgment.

[Signature Page Follows]

16

IN WITNESS WHEREOF, the Parties have executed this Agreement on the date and year first above written.

COMPANY
By:
	Name:
	Title:
EMPLOYEE
By:

[Signature Page to               Employment Agreement]

EXHIBIT A

Form of Release

This Agreement and Release (“Agreement”) is made by and between                      (“Employee”) and Athlon Holdings LP (the “Company”) (collectively, referred to as the “Parties” or individually referred to as a “Party”).  Capitalized terms used but not defined in this Agreement shall have the meanings set forth in the Employment Agreement (as defined below).

WHEREAS, the Parties have previously entered into that certain Employment Agreement, dated as of August 30, 2010 (the “Employment Agreement”); and

WHEREAS, in connection with the Employee’s termination of employment with the Company or a subsidiary or affiliate of the Company effective                 , 20    , the Parties wish to resolve any and all disputes, claims, complaints, grievances, charges, actions, petitions, and demands that the Employee may have against the Company and any of the Releasees as defined below, including, but not limited to, any and all claims arising out of or in any way related to Employee’s employment with or separation from the Company or its subsidiaries or affiliates.

NOW, THEREFORE, in consideration of the Severance Payments described in Section 4 of the Employment Agreement, which, pursuant to the Employment Agreement, are conditioned on the Employee’s execution and non-revocation of this Agreement, and in consideration of the mutual promises made herein, the Company and Employee hereby agree as follows:

1.Severance Payments; Salary and Benefits.  The Company agrees to provide Employee with the severance payments and benefits described in Section 4(b) of the Employment Agreement, payable at the times set forth in, and subject to the terms and conditions of, the Employment Agreement. In addition, to the extent not already paid, and subject to the terms and conditions of the Employment Agreement, the Company shall pay or provide to the Employee all other payments or benefits described in Section 3(c) of the Employment Agreement, subject to and in accordance with the terms thereof.

2.Release of Claims.  Employee agrees that the foregoing consideration represents settlement in full of all outstanding obligations owed to Employee by the Company, any of its direct or indirect subsidiaries and affiliates (including, without limitation,                                                    and its respective affiliated entities), and any of its current and former officers, directors, equity holders, managers, employees, agents, investors, attorneys, shareholders, administrators, affiliates, benefit plans, plan administrators, insurers, trustees, divisions, and subsidiaries and predecessor and successor corporations and assigns (collectively, the “Releasees”).  Employee, on his own behalf and on behalf of any of Employee’s affiliated companies or entities and any of their respective heirs, family members, executors, agents, and assigns, hereby and forever releases the Releasees from, and agrees not to sue concerning, or in any manner to institute, prosecute, or pursue, any claim, complaint, charge, duty, obligation, or cause of action relating to any matters of any kind, whether presently known or unknown, suspected or unsuspected, that Employee may possess against any of the Releasees arising from any omissions, acts, facts, or damages that have occurred up until and including the Effective Date (as defined in Section 7 below), including, without limitation:

(a)any and all claims relating to or arising from Employee’s employment or service relationship with the Company or any of its direct or indirect subsidiaries or affiliates and the termination of that relationship;

(b)any and all claims relating to, or arising from, Employee’s right to purchase, or actual purchase of any shares of stock or other equity interests of the Company or any of its affiliates, including, without limitation, any claims for fraud, misrepresentation, breach of fiduciary duty, breach of duty under applicable state corporate law, and securities fraud under any state or federal law;

(c)any and all claims for wrongful discharge of employment; termination in violation of public policy; discrimination; harassment; retaliation; breach of contract, both express and implied; breach of covenant of good faith and fair dealing, both express and implied; promissory estoppel; negligent or intentional infliction of emotional distress; fraud; negligent or intentional misrepresentation; negligent or intentional interference with contract or prospective economic advantage; unfair business practices; defamation; libel; slander; negligence; personal injury; assault; battery; invasion of privacy; false imprisonment; conversion; and disability benefits;

(d)any and all claims for violation of any federal, state, or municipal statute, including, but not limited to, Title VII of the Civil Rights Act of 1964; the Civil Rights Act of 1991; the Rehabilitation Act of 1973; the Americans with Disabilities Act of 1990; the Equal Pay Act; the Fair Labor Standards Act; the Fair Credit Reporting Act; the Age Discrimination in Employment Act of 1967; the Older Workers Benefit Protection Act; the Employee Retirement Income Security Act of 1974; the Worker Adjustment and Retraining Notification Act; the Family and Medical Leave Act; the Sarbanes-Oxley Act of 2002;

(e)any and all claims for violation of the federal or any state constitution;

(f)any and all claims arising out of any other laws and regulations relating to employment or employment discrimination;

(g)any claim for any loss, cost, damage, or expense arising out of any dispute over the non-withholding or other tax treatment of any of the proceeds received by Employee as a result of this Agreement; and

(h)any and all claims for attorneys’ fees and costs.

Employee agrees that the release set forth in this section shall be and remain in effect in all respects as a complete general release as to the matters released.  This release does not release claims that cannot be released as a matter of law, including, but not limited to, Employee’s right to file a charge with or participate in a charge by the Equal Employment Opportunity Commission, or any other local, state, or federal administrative body or government agency that is authorized to enforce or administer laws related to employment, against the Company (with the understanding that Employee’s release of claims herein bars Employee from recovering such monetary relief from the Company or any Releasee), claims for unemployment compensation or any state disability insurance benefits pursuant to the terms of applicable state law, claims to continued participation in certain of the Company’s group benefit plans pursuant to the terms and

2

conditions of COBRA, claims to any benefit entitlements vested as the date of separation of Employee’s employment, pursuant to written terms of any employee benefit plan of the Company or its affiliates and Employee’s right under applicable law and the Company’s D&O policy to seek indemnity for acts committed, or omissions, within the course and scope of the Employee’s employment duties.

3.Acknowledgment of Waiver of Claims under ADEA.  Employee understands and acknowledges that he is waiving and releasing any rights he may have under the Age Discrimination in Employment Act of 1967 (“ADEA”), and that this waiver and release is knowing and voluntary.  Employee understands and agrees that this waiver and release does not apply to any rights or claims that may arise under the ADEA after the Effective Date of this Agreement.  Employee understands and acknowledges that the consideration given for this waiver and release is in addition to anything of value to which Employee was already entitled.  Employee further understands and acknowledges that he has been advised by this writing that:  (a) he should consult with an attorney prior to executing this Agreement; (b) he has 21 days within which to consider this Agreement; (c) he has 7 days following his execution of this Agreement to revoke this Agreement; (d) this Agreement shall not be effective until after the revocation period has expired; and (e) nothing in this Agreement prevents or precludes Employee from challenging or seeking a determination in good faith of the validity of this waiver under the ADEA, nor does it impose any condition precedent, penalties, or costs for doing so, unless specifically authorized by federal law.  In the event Employee signs this Agreement and returns it to the Company in less than the 21 day period identified above, Employee hereby acknowledges that he has freely and voluntarily chosen to waive the time period allotted for considering this Agreement.

4.Severability.  In the event that any provision or any portion of any provision hereof or any surviving agreement made a part hereof becomes or is declared by a court of competent jurisdiction or arbitrator to be illegal, unenforceable, or void, this Agreement shall continue in full force and effect without said provision or portion of provision.

5.No Oral Modification.  This Agreement may only be amended in a writing signed by Employee and a duly authorized officer of the Company.

6.Governing Law; Dispute Resolution.  This Agreement shall be subject to the provisions of Sections 11(a) and 11(i) of the Employment Agreement.

7.Effective Date.  If the Employee has attained or is over the age of 40 as of the date of Employee’s termination of employment, then each Party has seven days after that Party signs this Agreement to revoke it and this Agreement will become effective on the eighth day after Employee signed this Agreement, so long as it has been signed by the Parties and has not been revoked by either Party before that date (the “Effective Date”).

8.Voluntary Execution of Agreement.  Employee understands and agrees that he executed this Agreement voluntarily, without any duress or undue influence on the part or behalf of the Company or any third party, with the full intent of releasing all of his claims against the Company and any of the other Releasees.  Employee acknowledges that:  (a) he has read this Agreement; (b) he has not relied upon any representations or statements made by the Company

3

that are not specifically set forth in this Agreement; (c) he has been represented in the preparation, negotiation, and execution of this Agreement by legal counsel of his own choice or has elected not to retain legal counsel; (d) he understands the terms and consequences of this Agreement and of the releases it contains; and (e) he is fully aware of the legal and binding effect of this Agreement.

9.The restrictive covenants contained in Sections 5-8 of the Employment Agreement remain in effect and are not superseded or modified by this Agreement.

IN WITNESS WHEREOF, the Parties have executed this Agreement on the respective dates set forth below.

Dated:
	ATHLON HOLDINGS LP
Dated:	By:
		Name:
		Title:

4

EX-10.5

Exhibit 10.5

ATHLON ENERGY INC.
2013 INCENTIVE AWARD PLAN

ARTICLE 1.

PURPOSE

The purpose of the Athlon Energy Inc. 2013 Incentive Award Plan (as it may be amended or restated from time to time, the “Plan”) is to promote the success and enhance the value of Athlon Energy Inc. (the “Company”) by linking the individual interests of the members of the Board, Employees, and Consultants to those of Company stockholders and by providing such individuals with an incentive for outstanding performance to generate superior returns to Company stockholders. The Plan is further intended to provide flexibility to the Company in its ability to motivate, attract, and retain the services of members of the Board, Employees, and Consultants upon whose judgment, interest, and special effort the successful conduct of the Company’s operation is largely dependent.

ARTICLE 2.

DEFINITIONS AND CONSTRUCTION

Wherever the following terms are used in the Plan they shall have the meanings specified below, unless the context clearly indicates otherwise. The singular pronoun shall include the plural where the context so indicates.

2.1“Administrator” shall mean the entity that conducts the general administration of the Plan as provided in Article 11. With reference to the duties of the Committee under the Plan which have been delegated to one or more persons pursuant to Section 11.6, or as to which the Board has assumed, the term “Administrator” shall refer to such person(s) unless the Committee or the Board has revoked such delegation or the Board has terminated the assumption of such duties.

2.2“Applicable Accounting Standards” shall mean Generally Accepted Accounting Principles in the United States, International Financial Reporting Standards or such other accounting principles or standards as may apply to the Company’s financial statements under United States federal securities laws from time to time.

2.3“Applicable Law” shall mean any applicable law, including without limitation: (i) provisions of the Code, the Securities Act, the Exchange Act and any rules or regulations thereunder; (ii) corporate, securities, tax or other laws, statutes, rules, requirements or regulations, whether federal, state, local or foreign; and (iii) rules of any securities exchange or automated quotation system on which the Shares are listed, quoted or traded.

2.4“Automatic Exercise Date” shall mean, with respect to an Option or a Stock Appreciation Right, the last business day of the applicable Option Term or Stock Appreciation Right Term that was established by the Administrator for such Option or Stock Appreciation Right (e.g., the last business day prior to the tenth anniversary of the date of grant of such

Option or Stock Appreciation Right if the Option or Stock Appreciation Right initially had a ten-year Option Term or Stock Appreciation Right Term, as applicable); provided that with respect to an Option or Stock Appreciation Right that has been amended pursuant to this Plan so as to alter the applicable Option Term or Stock Appreciation Right Term, “Automatic Exercise Date” shall mean the last business day of the applicable Option Term or Stock Appreciation Right Term that was established by the Administrator for such Option or Stock Appreciation Right as amended.

2.5“Award” shall mean an Option, a Restricted Stock award, a Restricted Stock Unit award, a Performance Award, a Dividend Equivalents award, a Stock Payment award or a Stock Appreciation Right, which may be awarded or granted under the Plan (collectively, “Awards”).

2.6“Award Agreement” shall mean any written notice, agreement, terms and conditions, contract or other instrument or document evidencing an Award, including through electronic medium, which shall contain such terms and conditions with respect to an Award as the Administrator shall determine consistent with the Plan.

2.7“Board” shall mean the Board of Directors of the Company.

2.8“Change in Control” shall mean and includes each of the following:

(a)A transaction or series of transactions (other than an offering of Common Stock to the general public through a registration statement filed with the Securities and Exchange Commission) whereby any “person” or related “group” of “persons” (as such terms are used in Sections 13(d) and 14(d)(2) of the Exchange Act) (other than the Company, any of its Subsidiaries, an employee benefit plan maintained by the Company or any of its Subsidiaries or a “person” that, prior to such transaction, directly or indirectly controls, is controlled by, or is under common control with, the Company) directly or indirectly acquires beneficial ownership (within the meaning of Rule 13d-3 under the Exchange Act) of securities of the Company possessing more than 50% of the total combined voting power of the Company’s securities outstanding immediately after such acquisition; or

(b)During any period of two consecutive years, individuals who, at the beginning of such period, constitute the Board together with any new Director(s) (other than a Director designated by a person who shall have entered into an agreement with the Company to effect a transaction described in Section 2.8(a) or Section 2.8(c)) whose election by the Board or nomination for election by the Company’s stockholders was approved by a vote of at least two-thirds of the Directors then still in office who either were Directors at the beginning of the two-year period or whose election or nomination for election was previously so approved, cease for any reason to constitute a majority thereof; or

(c)The consummation by the Company (whether directly involving the Company or indirectly involving the Company through one or more intermediaries) of (x) a merger, consolidation, reorganization, or business combination or (y) a sale or other disposition of all or substantially all of the Company’s assets in any single transaction or series of related

2

transactions or (z) the acquisition of assets or stock of another entity, in each case other than a transaction:

(i)which results in the Company’s voting securities outstanding immediately before the transaction continuing to represent (either by remaining outstanding or by being converted into voting securities of the Company or the person that, as a result of the transaction, controls, directly or indirectly, the Company or owns, directly or indirectly, all or substantially all of the Company’s assets or otherwise succeeds to the business of the Company (the Company or such person, the “Successor Entity”)) directly or indirectly, at least a majority of the combined voting power of the Successor Entity’s outstanding voting securities immediately after the transaction, and

(ii)after which no person or group beneficially owns voting securities representing 50% or more of the combined voting power of the Successor Entity; provided, however, that no person or group shall be treated for purposes of this Section 2.8(c)(ii) as beneficially owning 50% or more of the combined voting power of the Successor Entity solely as a result of the voting power held in the Company prior to the consummation of the transaction; or

(d)The Company’s stockholders approve a liquidation or dissolution of the Company.

In addition, if a Change in Control constitutes a payment event with respect to any portion of an Award that provides for the deferral of compensation and is subject to Section 409A of the Code, the transaction or event described in subsection (a), (b), (c) or (d) with respect to such Award (or portion thereof) must also constitute a “change in control event,” as defined in Treasury Regulation Section 1.409A-3(i)(5) to the extent required by Section 409A.  Notwithstanding the provisions of subsections (a), (b), (c) and (d) above, no event or occurrence shall constitute a Change in Control if such event or occurrence results in a Permitted Holder beneficially owning voting securities representing 50% or more of the combined voting power of the Company or its successor.

The Committee shall have full and final authority, which shall be exercised in its discretion, to determine conclusively whether a Change in Control of the Company has occurred pursuant to the above definition, and the date of the occurrence of such Change in Control and any incidental matters relating thereto; provided that any exercise of authority in conjunction with a determination of whether a Change in Control is a “change in control event” as defined in Treasury Regulation Section 1.409A-3(i)(5) shall be consistent with such regulation.

2.9“Code” shall mean the Internal Revenue Code of 1986, as amended from time to time, together with the regulations and official guidance promulgated thereunder.

2.10“Committee” shall mean the Compensation Committee of the Board, or another committee or subcommittee of the Board or the Compensation Committee, appointed as provided in Section 11.1.

3

2.11“Common Stock” shall mean the common stock of the Company, par value $0.0001 per share.

2.12“Company” shall have the meaning set forth in Article 1.

2.13“Consultant” shall mean any consultant or adviser engaged to provide services to the Company or any Subsidiary that qualifies as a consultant under the applicable rules of the Securities and Exchange Commission for registration of shares on a Form S-8 Registration Statement.

2.14“Director” shall mean a member of the Board, as constituted from time to time.

2.15“Dividend Equivalent” shall mean a right to receive the equivalent value (in cash or Shares) of dividends paid on Shares, awarded under Section 8.2.

2.16“DRO” shall mean a domestic relations order as defined by the Code or Title I of the Employee Retirement Income Security Act of 1974, as amended from time to time, or the rules thereunder.

2.17“Effective Date” shall mean the day prior to the Public Trading Date.

2.18“Eligible Individual” shall mean any person who is an Employee, a Consultant or a Non-Employee Director, as determined by the Committee.

2.19“Employee” shall mean any officer or other employee (as determined in accordance with Section 3401(c) of the Code) of the Company or of any Subsidiary.

2.20“Equity Restructuring” shall mean a nonreciprocal transaction between the Company and its stockholders, such as a stock dividend, stock split, spin-off, rights offering or recapitalization through a large, nonrecurring cash dividend, that affects the number or kind of Shares (or other securities of the Company) or the share price of Common Stock (or other securities) and causes a change in the per share value of the Common Stock underlying outstanding Awards.

2.21“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended from time to time.

2.22“Expiration Date” shall have the meaning given to such term in Section 12.1.

2.23“Fair Market Value” shall mean, as of any given date, the value of a Share determined as follows:

(a)If the Common Stock is listed on any (i) established securities exchange (such as the New York Stock Exchange, the NASDAQ Global Market and the NASDAQ Global Select Market), (ii) national market system or (iii) automated quotation system, its Fair Market Value shall be the closing sales price for a Share as quoted on such exchange or system for such date or, if there is no closing sales price for a Share on the date in question, the closing sales

4

price for a Share on the last preceding date for which such quotation exists, as reported in The Wall Street Journal or such other source as the Administrator deems reliable;

(b)If the Common Stock is not listed on an established securities exchange, national market system or automated quotation system, but the Common Stock is regularly quoted by a recognized securities dealer, its Fair Market Value shall be the mean of the high bid and low asked prices for such date or, if there are no high bid and low asked prices for a Share on such date, the high bid and low asked prices for a Share on the last preceding date for which such information exists, as reported in The Wall Street Journal or such other source as the Administrator deems reliable; or

(c)If the Common Stock is neither listed on an established securities exchange, national market system or automated quotation system nor regularly quoted by a recognized securities dealer, its Fair Market Value shall be established by the Administrator in good faith.

Notwithstanding the foregoing, with respect to any Award granted after the effectiveness of the Company’s registration statement relating to its initial public offering and prior to the Public Trading Date, the Fair Market Value shall mean the initial public offering price of a Share as set forth in the Company’s final prospectus relating to its initial public offering filed with the Securities and Exchange Commission.

2.24“Greater Than 10% Stockholder” shall mean an individual then owning (within the meaning of Section 424(d) of the Code) more than 10% of the total combined voting power of all classes of stock of the Company or any subsidiary corporation (as defined in Section 424(f) of the Code) or parent corporation thereof (as defined in Section 424(e) of the Code).

2.25“Holder” shall mean a person who has been granted an Award.

2.26“Incentive Stock Option” shall mean an Option that is intended to qualify as an incentive stock option and conforms to the applicable provisions of Section 422 of the Code.

2.27“Management Group” shall mean the group consisting of the directors, executive officers and other management personnel of the Company on the Effective Date, together with (1) any new directors whose election to the Board or whose nomination for election to the Board was approved by a vote of a majority of the members of the Board then still in office who were either directors on the Effective Date or whose election or nomination was previously so approved and (2) executive officers and other management personnel of the Company hired at a time when the directors on the Effective Date together with the directors so approved constituted a majority of the members of the Board.

2.28“Non-Employee Director” shall mean a Director of the Company who is not an Employee.

2.29“Non-Employee Director Equity Compensation Policy” shall have the meaning set forth in Section 4.5.

5

2.30“Non-Qualified Stock Option” shall mean an Option that is not an Incentive Stock Option.

2.31“Option” shall mean a right to purchase Shares at a specified exercise price, granted under Article 5. An Option shall be either a Non-Qualified Stock Option or an Incentive Stock Option; provided, however, that Options granted to Non-Employee Directors and Consultants shall only be Non-Qualified Stock Options.

2.32“Option Term” shall have the meaning set forth in Section 5.6.

2.33“Parent” shall mean any entity (other than the Company), whether domestic or foreign, in an unbroken chain of entities ending with the Company if each of the entities other than the Company beneficially owns, at the time of the determination, securities or interests representing at least fifty percent (50%) of the total combined voting power of all classes of securities or interests in one of the other entities in such chain.

2.34“Performance Award” shall mean a cash bonus award, stock bonus award, performance award or other incentive award that is paid in cash, Shares or a combination of both, awarded under Section 8.1.

2.35“Performance Criteria” shall mean the criteria (and adjustments) that the Committee selects for an Award for purposes of establishing the Performance Goal or Performance Goals for a Performance Period, determined as follows:

(a)The Performance Criteria that shall be used to establish Performance Goals may include but are not limited to: (i) net earnings (either before or after one or more of (A) interest, (B) taxes, (C) depreciation and (D) amortization); (ii) gross or net sales or revenue; (iii) net income (either before or after taxes); (iv) adjusted net income; (v) operating earnings or profit or one or more operating ratios; (vi) cash flow (including, but not limited to, operating cash flow and free cash flow); (vii) return on assets; (viii) return on capital; (ix) return on stockholders’ equity; (x) stock price or total stockholder return; (xi) return on sales; (xii) gross or net profit or operating margin; (xiii) costs; (xiv) expenses; (xv) working capital; (xvi) earnings per share; (xvii) adjusted earnings per share; (xviii) price per share; (xix) regulatory body approval for commercialization of a product; (xx) implementation, completion or attainment of objectives relating to research, development, regulatory, commercial, or strategic milestones or developments; (xxi) market share; (xxii) economic value; (xxiii) revenue, (xxiv) revenue growth, (xxv) capital expenditures, (xxvi) net borrowing, debt leverage levels, credit quality or debt ratings, (xxvii) the accomplishment of mergers, acquisitions, dispositions, joint ventures, public or private offerings or other financial transactions or similar extraordinary business transactions, (xxviii) net asset value per share, (xxix) economic value added, (xxx) individual business objectives, (xxxi) growth in production, (xxxii) added reserves, (xxxiii) growth in reserves per share, (xxxiv) inventory growth, (xxxv) environmental, health and safety performance, (xxxvi) effectiveness of hedging programs, (xxxvii) improvements in internal controls and policies and procedures, and (xxxviii) retention and recruitment of employees, any of which may be measured either in absolute terms or as compared to any incremental increase or decrease or as compared to results of a peer group or to market performance indicators or indices.

6

(b)The Administrator, in its discretion, may adjust the Performance Criteria for any Performance Period for such factors as the Administrator may determine, including, without limitation, in recognition of unusual or non-recurring events affecting the Company or changes in Applicable Law or Applicable Accounting Standards.

2.36“Performance Goals” shall mean, for a Performance Period, one or more goals established in writing by the Administrator for the Performance Period based upon one or more Performance Criteria. Depending on the Performance Criteria used to establish Performance Goals, Performance Goals may be expressed in terms of overall Company performance or the performance of a Subsidiary, division, business unit, or an individual. The achievement of each Performance Goal shall be determined, to the extent applicable, with reference to Applicable Accounting Standards.

2.37“Performance Period” shall mean one or more periods of time, which may be of varying and overlapping durations, as the Administrator may select, over which the attainment of one or more Performance Goals will be measured for the purpose of determining a Holder’s right to, and the payment of, an Award.

2.38“Performance Stock Unit” shall mean a Performance Award awarded under Section 8.1 which is denominated in units of value including dollar value of Shares.

2.39“Permitted Holder” shall mean each of (i) the Sponsors, (ii) the Management Group, (iii) any person that has no material assets other than the capital stock of the Company and, directly or indirectly, holds or acquires 100% of the total voting power of the voting stock of the Company, and of which no other person or group (within the meaning of Section 13(d)(3) or Section 14(d)(2) of the Exchange Act, or any successor provision), other than any of the other Permitted Holders specified in clauses (i) and (ii) above, holds more than 50% of the total voting power of the voting stock thereof and (iv) any group (within the meaning of Section 13(d)(3) or Section 14(d)(2) of the Exchange Act, or any successor provision) the members of which include any of the Permitted Holders specified in clauses (i) and (ii) above and that, directly or indirectly, hold or acquire beneficial ownership of the voting stock of the Company (a “Permitted Holder Group”), so long as (1) each member of the Permitted Holder Group has voting rights proportional to the percentage of ownership interests held or acquired by such member and (2) no person or other ‘‘group’’ (other than Permitted Holders specified in clauses (i) and (ii) above) beneficially owns more than 50% on a fully diluted basis of the voting stock held by the Permitted Holder Group.

2.40“Permitted Transferee” shall mean, with respect to a Holder, any “family member” of the Holder, as defined in the instructions to use the Form S-8 Registration Statement under the Securities Act, or any other transferee specifically approved by the Administrator after taking into account Applicable Law.

2.41“Plan” shall have the meaning set forth in Article 1.

2.42“Public Trading Date” shall mean the first date upon which Common Stock is listed (or approved for listing) upon notice of issuance on any securities exchange or designated

7

(or approved for designation) upon notice of issuance as a national market security on an interdealer quotation system.

2.43“Restricted Stock” shall mean Common Stock awarded under Article 6 that is subject to certain restrictions and may be subject to risk of forfeiture or repurchase.

2.44“Restricted Stock Unit” shall mean the right to receive Shares awarded under Article 7.

2.45“Securities Act” shall mean the Securities Act of 1933, as amended.

2.46“Shares” shall mean shares of Common Stock.

2.47“Sponsors” shall mean (i) the Apollo Investment Fund VII, L.P. and its parallel funds, Apollo Global Management, LLC and any of their respective affiliates other than any portfolio companies (collectively, the “Equity Investor”) and (ii) any person that forms a group (within the meaning of Section 13(d)(3) or Section 14(d)(2) of the Exchange Act, or any successor provision) with the Equity Investor; provided that the Equity Investor (x) owns a majority of the voting power and (y) controls a majority of the Board.

2.48“Stock Appreciation Right” shall mean a stock appreciation right granted under Article 9.

2.49“Stock Appreciation Right Term” shall have the meaning set forth in Section 9.4.

2.50“Stock Payment” shall mean (a) a payment in the form of Shares, or (b) an option or other right to purchase Shares, as part of a bonus, deferred compensation or other arrangement, awarded under Section 8.3.

2.51“Subsidiary” shall mean any entity (other than the Company), whether domestic or foreign, in an unbroken chain of entities beginning with the Company if each of the entities other than the last entity in the unbroken chain beneficially owns, at the time of the determination, securities or interests representing at least 50% of the total combined voting power of all classes of securities or interests in one of the other entities in such chain.

2.52“Substitute Award” shall mean an Award granted under the Plan upon the assumption of, or in substitution for, outstanding equity awards granted by a company or other entity in connection with a corporate transaction, such as a merger, combination, consolidation or acquisition of property or stock; provided, however, that in no event shall the term “Substitute Award” be construed to refer to an award made in connection with the cancellation and repricing of an Option or Stock Appreciation Right.

2.53“Termination of Service” shall mean:

(a)As to a Consultant, the time when the engagement of a Holder as a Consultant to the Company or a Subsidiary is terminated for any reason, with or without cause, including, without limitation, by resignation, discharge, death, disability or retirement, but

8

excluding terminations where the Consultant simultaneously commences or remains in employment or service with the Company or any Subsidiary.

(b)As to a Non-Employee Director, the time when a Holder who is a Non-Employee Director ceases to be a Director for any reason, including, without limitation, a termination by resignation, failure to be elected, death, disability or retirement, but excluding terminations where the Holder simultaneously commences or remains in employment or service with the Company or any Subsidiary.

(c)As to an Employee, the time when the employee-employer relationship between a Holder and the Company or any Subsidiary is terminated for any reason, including, without limitation, a termination by resignation, discharge, death, disability or retirement; but excluding terminations where the Holder simultaneously commences or remains in employment or service with the Company or any Subsidiary.

The Administrator, in its discretion, shall determine the effect of all matters and questions relating to any Termination of Service, including, without limitation, the question of whether a Termination of Service resulted from a discharge for cause and all questions of whether particular leaves of absence constitute a Termination of Service; provided, however, that, with respect to Incentive Stock Options, unless the Administrator otherwise provides in the terms of the Award Agreement or otherwise, or as otherwise required by Applicable Law, a leave of absence, change in status from an employee to an independent contractor or other change in the employee-employer relationship shall constitute a Termination of Service only if, and to the extent that, such leave of absence, change in status or other change interrupts employment for the purposes of Section 422(a)(2) of the Code. For purposes of the Plan, a Holder’s employee-employer relationship or consultancy relations shall be deemed to be terminated in the event that the Subsidiary employing or contracting with such Holder ceases to remain an Subsidiary following any merger, sale of stock or other corporate transaction or event (including, without limitation, a spin-off).

ARTICLE 3.

SHARES SUBJECT TO THE PLAN

3.1Number of Shares.

(a)Subject to Sections 3.1(b) and 12.2, the aggregate number of Shares which may be issued or transferred pursuant to Awards under the Plan is the sum of: (i)             , and (ii) an annual increase on the first day of each calendar year beginning January 1, 2014 and ending on and including the last January 1 prior to the Expiration Date, equal to the lesser of (A)                Shares, (B) 4% of the Shares outstanding (on an as-converted basis) on the final day of the immediately preceding calendar year and (C) such smaller number of Shares as determined by the Board; provided, however, no more than               Shares may be issued upon the exercise of Incentive Stock Options.

(b)To the extent all or a portion of an Award is forfeited, expires, lapses for any reason, or is settled for cash without the delivery of Shares to the Holder, any Shares subject

9

to such Award or portion thereof shall, to the extent of such forfeiture, expiration, lapse or cash settlement, again be available for the grant of an Award under the Plan. Any Shares repurchased by or surrendered to the Company under Section 6.4 so that such Shares are returned to the Company shall again be available for the grant of an Award under the Plan. The payment of Dividend Equivalents in cash in conjunction with any outstanding Awards shall not be counted against the Shares available for issuance under the Plan. Notwithstanding the provisions of this Section 3.1(b), no Shares may again be optioned, granted or awarded if such action would cause an Incentive Stock Option to fail to qualify as an incentive stock option under Section 422 of the Code.

(c)To the extent permitted by Applicable Law, Substitute Awards shall not reduce the Shares authorized for grant under the Plan.

3.2Stock Distributed. Any Shares distributed pursuant to an Award may consist, in whole or in part, of authorized and unissued Common Stock, treasury Common Stock or Common Stock purchased on the open market.

3.3Limitation on Awards to Non-Employee Directors. Notwithstanding any provision in the Plan to the contrary, and subject to Section 12.2, for any one year no Non-Employee Director shall be granted Awards that have a grant date fair value, as determined in accordance with Financial Accounting Standards Board Accounting Standards Codification Topic 718, or any successor thereto, in excess of $700,000.

ARTICLE 4.

GRANTING OF AWARDS

4.1Participation. The Administrator may, from time to time, select from among all Eligible Individuals, those to whom an Award shall be granted and shall determine the nature and amount of each Award, which shall not be inconsistent with the requirements of the Plan. Except as provided in Section 4.5 regarding the grant of Awards pursuant to the Non-Employee Director Equity Compensation Policy, no Eligible Individual shall have any right to be granted an Award pursuant to the Plan.

4.2Award Agreement. Each Award shall be evidenced by an Award Agreement that sets forth the terms, conditions and limitations for such Award, which may include the term of the Award, the provisions applicable in the event of the Holder’s Termination of Service, and the Company’s authority to unilaterally or bilaterally amend, modify, suspend, cancel or rescind an Award. Award Agreements evidencing Incentive Stock Options shall contain such terms and conditions as may be necessary to meet the applicable provisions of Section 422 of the Code.

4.3Limitations Applicable to Section 16 Persons. Notwithstanding any other provision of the Plan, the Plan, and any Award granted or awarded to any individual who is then subject to Section 16 of the Exchange Act, shall be subject to any additional limitations set forth in any applicable exemptive rule under Section 16 of the Exchange Act (including Rule 16b-3 of the Exchange Act and any amendments thereto) that are requirements for the application of such exemptive rule. To the extent permitted by Applicable Law, the Plan and Awards granted or

10

awarded hereunder shall be deemed amended to the extent necessary to conform to such applicable exemptive rule.

4.4At-Will Employment; Voluntary Participation. Nothing in the Plan or Award Agreement shall confer upon any Holder any right to continue in the employ of, or as a Director or Consultant for, the Company or any Subsidiary, or shall interfere with or restrict in any way the rights of the Company and any Subsidiary, which rights are hereby expressly reserved, to discharge any Holder at any time for any reason whatsoever, with or without cause, and with or without notice, or to terminate or change all other terms and conditions of employment or engagement, except to the extent expressly provided otherwise in a written agreement between the Holder and the Company or any Subsidiary. Participation by each Holder in the Plan shall be voluntary and nothing in the Plan shall be construed as mandating that any Eligible Individual shall participate in the Plan.

4.5Non-Employee Director Awards. The Administrator, in its discretion, may provide that Awards granted to Non-Employee Directors shall be granted pursuant to a written nondiscretionary formula established by the Administrator (the “Non-Employee Director Equity Compensation Policy”), subject to the limitations of the Plan. The Non-Employee Director Equity Compensation Policy shall set forth the type of Award(s) to be granted to Non-Employee Directors, the number of Shares to be subject to Non-Employee Director Awards, the conditions on which such Awards shall be granted, become exercisable and/or payable and expire, and such other terms and conditions as the Administrator shall determine in its discretion. The Non-Employee Director Equity Compensation Policy may be modified by the Administrator from time to time in its discretion.

4.6Stand-Alone and Tandem Awards. Awards granted pursuant to the Plan may, in the discretion of the Administrator, be granted either alone, in addition to, or in tandem with, any other Award granted pursuant to the Plan. Awards granted in addition to or in tandem with other Awards may be granted either at the same time as or at a different time from the grant of such other Awards.

ARTICLE 5.

OPTIONS

5.1Granting of Options to Eligible Individuals. The Administrator is authorized to grant Options to Eligible Individuals from time to time, in its discretion, on such terms and conditions as it may determine, which shall not be inconsistent with the Plan.

5.2Option Exercise Price. The exercise price per Share subject to each Option shall be set by the Administrator, but shall not be less than 100% of the Fair Market Value of a Share on the date the Option is granted (or, as to Incentive Stock Options, on the date the Option is modified, extended or renewed for purposes of Section 424(h) of the Code) unless otherwise determined by the Administrator. In addition, in the case of Incentive Stock Options granted to a Greater Than 10% Stockholder, such price shall not be less than 110% of the Fair Market Value of a Share on the date the Option is granted (or the date the Option is modified, extended or renewed for purposes of Section 424(h) of the Code).

11

5.3Option Vesting.

(a)The period during which the right to exercise, in whole or in part, an Option vests in the Holder shall be set by the Administrator and the Administrator may determine that an Option may not be exercised in whole or in part for a specified period after it is granted. Such vesting may be based on service with the Company or any Subsidiary or any other criteria selected by the Administrator, including Performance Goals or Performance Criteria. At any time after the grant of an Option, the Administrator, in its discretion and subject to whatever terms and conditions it selects, may accelerate the period during which an Option vests.

(b)No portion of an Option which is unexercisable at a Holder’s Termination of Service shall thereafter become exercisable, except as may be otherwise provided by the Administrator either in the Award Agreement evidencing the grant of an Option or by action of the Administrator following the grant of the Option. Unless otherwise determined by the Administrator in the Award Agreement or by action of the Administrator following the grant of the Option, the portion of an Option that is unexercisable at a Holder’s Termination of Service shall automatically expire thirty (30) days following such Termination of Service.

5.4Manner of Exercise.  All or a portion of an exercisable Option shall be deemed exercised upon delivery of all of the following to the Secretary of the Company, the stock administrator of the Company or such other person or entity designated by the Administrator, or his, her or its office, as applicable:

(a)A written or electronic notice complying with the applicable rules established by the Administrator stating that the Option, or a portion thereof, is exercised. The notice shall be signed by the Holder or other person then entitled to exercise the Option or such portion of the Option.

(b)Such representations and documents as the Administrator, in its discretion, deems necessary or advisable to effect compliance with Applicable Law.  The Administrator may, in its discretion, also take whatever additional actions it deems appropriate to effect such compliance including, without limitation, placing legends on share certificates and issuing stop-transfer notices to agents and registrars.

(c)In the event that the Option shall be exercised by any person or persons other than the Holder, appropriate proof of the right of such person or persons to exercise the Option, as determined in the discretion of the Administrator.

(d)Full payment of the exercise price and applicable withholding taxes for the shares with respect to which the Option, or portion thereof, is exercised, in a manner permitted by Section 10.1 and Section 10.2.

5.5Partial Exercise. An exercisable Option may be exercised in whole or in part. However, an Option shall not be exercisable with respect to fractional Shares unless otherwise determined by the Administrator and the Administrator may require that, by the terms of the Option, a partial exercise must be with respect to a minimum number of shares.

12

5.6Option Term.  The term of each Option (the “Option Term”) shall be set by the Administrator in its discretion; provided, however, that the Option Term shall not be more than ten (10) years from the date the Option is granted, or five (5) years from the date an Incentive Stock Option is granted to a Greater Than 10% Stockholder.  The Administrator shall determine the time period, including the time period following a Termination of Service, during which the Holder has the right to exercise the vested Options, which time period may not extend beyond the last day of the Option Term.  Except as limited by the requirements of Section 409A of the Code or the first sentence of this Section 5.6, the Administrator may extend the Option Term of any outstanding Option, and may extend the time period during which vested Options may be exercised, in connection with any Termination of Service of the Holder, and may amend, subject to Section 12.1, any other term or condition of such Option relating to such a Termination of Service.

5.7Expiration of Option Term: Automatic Exercise of In-The-Money Options. Unless otherwise provided by the Administrator (in an Award Agreement or otherwise) or as otherwise directed by an Option Holder in writing to the Company, each Option outstanding on the Automatic Exercise Date with an exercise price per share that is less than the Fair Market Value per share of Common Stock as of such date shall automatically and without further action by the Option Holder or the Company be exercised on the Automatic Exercise Date. In the discretion of the Administrator, payment of the exercise price of any such Option shall be made pursuant to Section 10.1(b) or Section 10.1(c) and the Company or any Subsidiary shall deduct or withhold an amount sufficient to satisfy all taxes associated with such exercise in accordance with Section 10.2. Unless otherwise determined by the Administrator, this Section 5.7 shall not apply to an Option if the Holder of such Option incurs a Termination of Service on or before the Automatic Exercise Date. For the avoidance of doubt, no Option with an exercise price per share that is equal to or greater than the Fair Market Value per share of Common Stock on the Automatic Exercise Date shall be exercised pursuant to this Section 5.7.

5.8Notification Regarding Disposition. The Holder shall give the Company prompt written or electronic notice of any disposition of Shares acquired by exercise of an Incentive Stock Option which occurs within (a) two years from the date of granting (including the date the Option is modified, extended or renewed for purposes of Section 424(h) of the Code) such Option to such Holder, or (b) one year after the transfer of such Shares to such Holder.

ARTICLE 6.

RESTRICTED STOCK

6.1Award of Restricted Stock.

(a)The Administrator is authorized to grant Restricted Stock to Eligible Individuals, and shall determine the terms and conditions, including the restrictions applicable to each award of Restricted Stock, which terms and conditions shall not be inconsistent with the Plan, and may impose such conditions on the issuance of such Restricted Stock as it deems appropriate.

13

(b)The Administrator shall establish the purchase price, if any, and form of payment for Restricted Stock; provided, however, that if a purchase price is charged, such purchase price shall be no less than the par value, if any, of the Shares to be purchased, unless otherwise permitted by Applicable Law. In all cases, legal consideration shall be required for each issuance of Restricted Stock.

6.2Rights as Stockholders. Subject to Section 6.4, upon issuance of Restricted Stock, the Holder shall have, unless otherwise provided by the Administrator, all the rights of a stockholder with respect to said Shares, subject to the restrictions in each individual Award Agreement, including the right to receive all dividends and other distributions paid or made with respect to the Shares; provided, however, that, in the discretion of the Administrator, any extraordinary distributions with respect to the Shares shall be subject to the restrictions set forth in Section 6.3.

6.3Restrictions. All shares of Restricted Stock (including any shares received by Holders thereof with respect to shares of Restricted Stock as a result of stock dividends, stock splits or any other form of recapitalization) shall, in the terms of each individual Award Agreement, be subject to such restrictions and vesting requirements as the Administrator shall provide. Such restrictions may include, without limitation, restrictions concerning voting rights and transferability and such restrictions may lapse separately or in combination at such times and pursuant to such circumstances or based on such criteria as selected by the Administrator, including, without limitation, criteria based on the Holder’s duration of employment, directorship or consultancy with the Company, Performance Goals, Performance Criteria, Company performance, individual performance or other criteria selected by the Administrator. By action taken after the Restricted Stock is issued, the Administrator may, on such terms and conditions as it may determine to be appropriate, accelerate the vesting of such Restricted Stock by removing any or all of the restrictions imposed by the terms of the applicable Award Agreement. Unless otherwise determined by the Administrator, Restricted Stock may not be sold or encumbered until all restrictions are terminated or expire.

6.4Repurchase or Forfeiture of Restricted Stock. Except as otherwise determined by the Administrator at the time of the grant of the Award or thereafter, (a) if no price was paid by the Holder for the Restricted Stock, upon a Termination of Service during the applicable restriction period, the Holder’s rights in unvested Restricted Stock then subject to restrictions shall lapse, and such Restricted Stock shall be surrendered to the Company and cancelled without consideration, and (b) if a price was paid by the Holder for the Restricted Stock, upon a Termination of Service during the applicable restriction period, the Company shall have the right to repurchase from the Holder the unvested Restricted Stock then subject to restrictions at a cash price per share equal to the price paid by the Holder for such Restricted Stock or such other amount as may be specified in the applicable Award Agreement.

6.5Certificates for Restricted Stock. Restricted Stock granted pursuant to the Plan may be evidenced in such manner as the Administrator shall determine. Certificates or book entries evidencing shares of Restricted Stock shall include an appropriate legend referring to the terms, conditions, and restrictions applicable to such Restricted Stock. The Company, in its discretion, may (a) retain physical possession of any stock certificate evidencing shares of Restricted Stock until the restrictions thereon shall have lapsed and/or (b) require that the stock

14

certificates evidencing shares of Restricted Stock be held in custody by a designated escrow agent (which may but need not be the Company) until the restrictions thereon shall have lapsed and that the Holder deliver a stock power, endorsed in blank, relating to such Restricted Stock.

6.6Section 83(b) Election. If a Holder makes an election under Section 83(b) of the Code to be taxed with respect to the Restricted Stock as of the date of transfer of the Restricted Stock rather than as of the date or dates upon which the Holder would otherwise be taxable under Section 83(a) of the Code, the Holder shall be required to deliver a copy of such election to the Company promptly after filing such election with the Internal Revenue Service.

ARTICLE 7.

RESTRICTED STOCK UNITS

7.1Grant of Restricted Stock Units. The Administrator is authorized to grant Awards of Restricted Stock Units to any Eligible Individual selected by the Administrator in such amounts and subject to such terms and conditions as determined by the Administrator.

7.2Purchase Price. The Administrator shall specify the purchase price, if any, to be paid by the Holder to the Company with respect to any Restricted Stock Unit award; provided, however, that value of the consideration shall not be less than the par value of a Share, unless otherwise permitted by Applicable Law.

7.3Vesting of Restricted Stock Units. At the time of grant, the Administrator shall specify the date or dates on which the Restricted Stock Units shall become fully vested and nonforfeitable, and may specify such conditions to vesting as it deems appropriate, including, without limitation, vesting based upon the Holder’s duration of service to the Company or any Subsidiary, Company performance, individual performance or other specific criteria, in each case on a specified date or dates or over any period or periods, as determined by the Administrator.

7.4Maturity and Payment. At the time of grant, the Administrator shall specify the maturity date applicable to each grant of Restricted Stock Units, which shall be no earlier than the vesting date or dates of the Award and may be determined at the election of the Holder (if permitted by the applicable Award Agreement); provided that, except as otherwise set forth in an applicable Award Agreement, the maturity date relating to each Restricted Stock Unit shall not occur following the later of (a) the 15th day of the third month following the end of the calendar year in which the applicable portion of the Restricted Stock Unit vests; or (b) the 15th day of the third month following the end of the Company’s fiscal year in which the applicable portion of the Restricted Stock Unit vests. On the maturity date, the Company shall, subject to Section 10.4, transfer to the Holder one unrestricted, fully transferable Share for each Restricted Stock Unit scheduled to be paid out on such date and not previously forfeited, or in the discretion of the Administrator, an amount in cash equal to the Fair Market Value of such Shares on the maturity date or a combination of cash and Common Stock as determined by the Administrator.

7.5No Rights as a Stockholder. Unless otherwise determined by the Administrator, a Holder of Restricted Stock Units shall possess no incidents of ownership with respect to the

15

Shares represented by such Restricted Stock Units, unless and until such Shares are transferred to the Holder pursuant to the terms of this Plan and the Award Agreement.

ARTICLE 8.

PERFORMANCE AWARDS, DIVIDEND EQUIVALENTS, STOCK PAYMENTS

8.1Performance Awards. The Administrator is authorized to grant Performance Awards, including Awards of Performance Stock Units and other Awards determined in the Administrator’s discretion from time to time, to any Eligible Individual. The value of Performance Awards, including Performance Stock Units, may be linked to the attainment of the Performance Goals or other specific criteria, whether or not objective, determined by the Administrator, in each case on a specified date or dates or over any period or periods and in such amounts as may be determined by the Administrator.

8.2Dividend Equivalents.

(a)Dividend Equivalents may be granted by the Administrator based on dividends declared on the Common Stock, to be credited as of dividend payment dates with respect to dividends with record dates that occur during the period between the date an Award is granted to a Holder and the date such Award vests, is exercised, is distributed or expires, as determined by the Administrator. Such Dividend Equivalents shall be converted to cash or additional Shares by such formula and at such time and subject to such restrictions and limitations as may be determined by the Administrator.

8.3Stock Payments. The Administrator is authorized to make Stock Payments to any Eligible Individual. The number or value of Shares of any Stock Payment shall be determined by the Administrator and may be based upon one or more Performance Goals or any other specific criteria, including service to the Company or any Subsidiary, determined by the Administrator. Shares underlying a Stock Payment which is subject to a vesting schedule or other conditions or criteria set by the Administrator shall not be issued until those conditions have been satisfied. Unless otherwise provided by the Administrator, a Holder of a Stock Payment shall have no rights as a Company stockholder with respect to such Stock Payment until such time as the Stock Payment has vested and the Shares underlying the Award have been issued to the Holder. Stock Payments may, but are not required to, be made in lieu of base salary, bonus, fees or other cash compensation otherwise payable to such Eligible Individual.

8.4Purchase Price. The Administrator may establish the purchase price of a Performance Award or Shares distributed as a Stock Payment award; provided, however, that value of the consideration shall not be less than the par value of a Share, unless otherwise permitted by Applicable Law.

16

ARTICLE 9.

STOCK APPRECIATION RIGHTS

9.1Grant of Stock Appreciation Rights.

(a)The Administrator is authorized to grant Stock Appreciation Rights to Eligible Individuals from time to time, in its discretion, on such terms and conditions as it may determine, which shall not be inconsistent with the Plan.

(b)A Stock Appreciation Right shall entitle the Holder (or other person entitled to exercise the Stock Appreciation Right pursuant to the Plan) to exercise all or a specified portion of the Stock Appreciation Right (to the extent then exercisable pursuant to its terms) and to receive from the Company an amount determined by multiplying the difference obtained by subtracting the exercise price per share of the Stock Appreciation Right from the Fair Market Value on the date of exercise of the Stock Appreciation Right by the number of Shares with respect to which the Stock Appreciation Right shall have been exercised, subject to any limitations the Administrator may impose. Unless otherwise determined by the Administrator, the exercise price per Share subject to each Stock Appreciation Right shall be set by the Administrator, but shall not be less than 100% of the Fair Market Value on the date the Stock Appreciation Right is granted.

9.2Stock Appreciation Right Vesting.

(a)The period during which the right to exercise, in whole or in part, a Stock Appreciation Right vests in the Holder shall be set by the Administrator, and the Administrator may determine that a Stock Appreciation Right may not be exercised in whole or in part for a specified period after it is granted. Such vesting may be based on service with the Company or any Subsidiary, Performance Criteria, Performance Goals or any other criteria selected by the Administrator. At any time after grant of a Stock Appreciation Right, the Administrator, in its discretion and subject to whatever terms and conditions it selects, may accelerate the period during which a Stock Appreciation Right vests.

(b)No portion of a Stock Appreciation Right which is unexercisable at a Holder’s Termination of Service shall thereafter become exercisable, except as may be otherwise provided by the Administrator in an Award Agreement or by action of the Administrator following the grant of the Stock Appreciation Right. Unless otherwise determined by the Administrator in the Award Agreement or by action of the Administrator following the grant of the Stock Appreciation Right, the portion of a Stock Appreciation Right which is unexercisable at a Holder’s Termination of Service shall automatically expire thirty (30) days following such Termination of Service.

9.3Manner of Exercise. All or a portion of an exercisable Stock Appreciation Right shall be deemed exercised upon delivery of all of the following to the Secretary of the Company, the stock administrator of the Company, or such other person or entity designated by the Administrator, or his, her or its office, as applicable:

(a)A written or electronic notice complying with the applicable rules established by the Administrator stating that the Stock Appreciation Right, or a portion thereof, is exercised. The notice shall be signed by the Holder or other person then entitled to exercise the Stock Appreciation Right or such portion of the Stock Appreciation Right.

17

(b)Such representations and documents as the Administrator, in its discretion, deems necessary or advisable to effect compliance with Applicable Law. The Administrator, in its discretion, may also take whatever additional actions it deems appropriate to effect such compliance, including, without limitation, placing legends on share certificates and issuing stop-transfer notices to agents and registrars.

(c)In the event that the Stock Appreciation Right shall be exercised by any person or persons other than the Holder, appropriate proof of the right of such person or persons to exercise the Stock Appreciation Right, as determined in the discretion of the Administrator.

(d)Full payment of the exercise price and applicable withholding taxes for the Shares with respect to which the Stock Appreciation Right, or portion thereof, is exercised, in a manner permitted by Section 10.1 and Section 10.2.

9.4Stock Appreciation Right Term. The term of each Stock Appreciation Right (the “Stock Appreciation Right Term”) shall be set by the Administrator in its discretion; provided, however, that the Stock Appreciation Right Term shall not be more than ten (10) years from the date the Stock Appreciation Right is granted. The Administrator shall determine the time period, including the time period following a Termination of Service, during which the Holder has the right to exercise the vested Stock Appreciation Rights, which time period may not extend beyond the last day of the Stock Appreciation Right Term applicable to such Stock Appreciation Right. Except as limited by the requirements of Section 409A of the Code or the first sentence of this Section 9.4, the Administrator may extend the Stock Appreciation Right Term of any outstanding Stock Appreciation Right, and may extend the time period during which vested Stock Appreciation Rights may be exercised, in connection with any Termination of Service of the Holder, and may amend, subject to Section 14.1, any other term or condition of such Stock Appreciation Right relating to such a Termination of Service.

9.5Payment. Payment of the amounts payable with respect to Stock Appreciation Rights pursuant to this Article 9 shall be in cash, Shares (based on Fair Market Value as of the date the Stock Appreciation Right is exercised), or a combination of both, as determined by the Administrator.

9.6Expiration of Stock Appreciation Right Term: Automatic Exercise of In-The-Money Stock Appreciation Rights. Unless otherwise provided by the Administrator (in an Award Agreement or otherwise) or as otherwise directed by a Stock Appreciation Right Holder in writing to the Company, each Stock Appreciation Right outstanding on the Automatic Exercise Date with an exercise price per share that is less than the Fair Market Value per share of Common Stock as of such date shall automatically and without further action by the Stock Appreciation Right Holder or the Company be exercised on the Automatic Exercise Date. In the discretion of the Administrator, the Company or any Subsidiary shall deduct or withhold an amount sufficient to satisfy all taxes associated with such exercise in accordance with Section 10.2. Unless otherwise determined by the Administrator, this Section 9.6 shall not apply to a Stock Appreciation Right if the Holder of such Stock Appreciation Right incurs a Termination of Service on or before the Automatic Exercise Date. For the avoidance of doubt, no Stock Appreciation Right with an exercise price per share that is equal to or greater than the Fair

18

Market Value per share of Common Stock on the Automatic Exercise Date shall be exercised pursuant to this Section 9.6.

ARTICLE 10.

ADDITIONAL TERMS OF AWARDS

10.1Payment. The Administrator shall determine the methods by which payments by any Holder with respect to any Awards granted under the Plan shall be made, including, without limitation: (a) cash or check, (b) Shares (including, in the case of payment of the exercise price of an Award, Shares issuable pursuant to the exercise of the Award) held for such period of time as may be required by the Administrator in order to avoid adverse accounting consequences, in each case, having a Fair Market Value on the date of delivery equal to the aggregate payments required, (c) delivery of a written or electronic notice that the Holder has placed a market sell order with a broker acceptable to the Company with respect to Shares then issuable upon exercise or vesting of an Award, and that the broker has been directed to pay a sufficient portion of the net proceeds of the sale to the Company in satisfaction of the aggregate payments required; provided that payment of such proceeds is then made to the Company upon settlement of such sale, or (d) any other form of legal consideration acceptable to the Administrator in its discretion. The Administrator shall also determine the methods by which Shares shall be delivered or deemed to be delivered to Holders. Notwithstanding any other provision of the Plan to the contrary, no Holder who is a Director or an “executive officer” of the Company within the meaning of Section 13(k) of the Exchange Act shall be permitted to make payment with respect to any Awards granted under the Plan, or continue any extension of credit with respect to such payment, with a loan from the Company or a loan arranged by the Company in violation of Section 13(k) of the Exchange Act.

10.2Tax Withholding. The Company or any Subsidiary shall have the authority and the right to deduct or withhold, or require a Holder to remit to the Company, an amount sufficient to satisfy federal, state, local and foreign taxes (including the Holder’s FICA, employment tax or other social security contribution obligation) required by law to be withheld with respect to any taxable event concerning a Holder arising as a result of the Plan. The Administrator, in its discretion and in satisfaction of the foregoing requirement, may withhold, or allow a Holder to elect to have the Company withhold, Shares otherwise issuable under an Award (or allow the surrender of Shares). Unless otherwise determined by the Administrator, the number of Shares which may be so withheld or surrendered shall be limited to the number of Shares which have a Fair Market Value on the date of withholding or repurchase equal to the aggregate amount of such liabilities based on the minimum statutory withholding rates for federal, state, local and foreign income tax and payroll tax purposes that are applicable to such supplemental taxable income. The Administrator shall determine the fair market value of the Shares, consistent with applicable provisions of the Code, for tax withholding obligations due in connection with a broker-assisted cashless Option or Stock Appreciation Right exercise involving the sale of Shares to pay the Option or Stock Appreciation Right exercise price or any tax withholding obligation.

19

10.3Transferability of Awards.

(a)Except as otherwise provided in Section 10.3(b):

(i)No Award under the Plan may be sold, pledged, assigned or transferred in any manner other than by will or the laws of descent and distribution or, subject to the consent of the Administrator, pursuant to a DRO, unless and until such Award has been exercised, or the Shares underlying such Award have been issued, and all restrictions applicable to such Shares have lapsed;

(ii)No Award or interest or right therein shall be liable for the debts, contracts or engagements of the Holder or the Holder’s successors in interest or shall be subject to disposition by transfer, alienation, anticipation, pledge, hypothecation, encumbrance, assignment or any other means whether such disposition be voluntary or involuntary or by operation of law by judgment, levy, attachment, garnishment or any other legal or equitable proceedings (including bankruptcy), and any attempted disposition thereof shall be null and void and of no effect, except to the extent that such disposition is permitted by Section 10.3(a)(i); and

(iii)During the lifetime of the Holder, only the Holder may exercise an Award (or any portion thereof) granted to such Holder under the Plan, unless it has been disposed of pursuant to a DRO; after the death of the Holder, any exercisable portion of an Award may, prior to the time when such portion becomes unexercisable under the Plan or the Award Agreement, be exercised by the Holder’s personal representative or by any person empowered to do so under the deceased Holder’s will or under the then-applicable laws of descent and distribution.

(b)Notwithstanding Section 10.3(a), the Administrator, in its discretion, may determine to permit a Holder to transfer an Award other than an Incentive Stock Option to any one or more Permitted Transferees, subject to the following terms and conditions: (i) an Award transferred to a Permitted Transferee shall not be assignable or transferable by the Permitted Transferee other than by will or the laws of descent and distribution; (ii) an Award transferred to a Permitted Transferee shall continue to be subject to all the terms and conditions of the Award as applicable to the original Holder (other than the ability to further transfer the Award); and (iii) the Holder and the Permitted Transferee shall execute any and all documents requested by the Administrator, including, without limitation documents to (A) confirm the status of the transferee as a Permitted Transferee, (B) satisfy any requirements for an exemption for the transfer under Applicable Law and (C) evidence the transfer.

(c)Notwithstanding Section 10.3(a), a Holder may, in the manner determined by the Administrator, designate a beneficiary to exercise the rights of the Holder and to receive any distribution with respect to any Award upon the Holder’s death. A beneficiary, legal guardian, legal representative, or other person claiming any rights pursuant to the Plan is subject to all terms and conditions of the Plan and any Award Agreement applicable to the Holder, except to the extent the Plan and Award Agreement otherwise provide, and to any additional restrictions deemed necessary or appropriate by the Administrator. If the Holder is married or a domestic partner in a domestic partnership qualified under Applicable Law and resides in a community property state, a designation of a person other than the Holder’s spouse or domestic

20

partner, as applicable, as the Holder’s beneficiary with respect to more than 50% of the Holder’s interest in the Award shall not be effective without the prior written or electronic consent of the Holder’s spouse or domestic partner. If no beneficiary has been designated or survives the Holder, payment shall be made to the person entitled thereto pursuant to the Holder’s will or the laws of descent and distribution. Subject to the foregoing, a beneficiary designation may be changed or revoked by a Holder at any time; provided that the change or revocation is filed with the Administrator prior to the Holder’s death.

10.4Conditions to Issuance of Shares.

(a)Notwithstanding anything herein to the contrary, the Company shall not be required to issue or deliver any certificates or make any book entries evidencing Shares issuable pursuant to any Award, unless and until the Board or the Committee has determined, with advice of counsel, that the issuance of such Shares is in compliance with Applicable Law and the Shares are covered by an effective registration statement or applicable exemption from registration. In addition to the terms and conditions provided herein, the Board or the Committee may require that a Holder make such reasonable covenants, agreements and representations as the Board or the Committee, in its discretion, deems advisable in order to comply with Applicable Law.

(b)All Share certificates delivered pursuant to the Plan and all Shares issued pursuant to book entry procedures are subject to any stop-transfer orders and other restrictions as the Administrator deems necessary or advisable to comply with Applicable Law. The Administrator may place legends on any Share certificate or book entry to reference restrictions applicable to the Shares.

(c)The Administrator shall have the right to require any Holder to comply with any timing or other restrictions with respect to the settlement, distribution or exercise of any Award, including a window-period limitation, as may be imposed in the discretion of the Administrator.

(d)No fractional Shares shall be issued and the Administrator, in its discretion, shall determine whether cash shall be given in lieu of fractional Shares or whether such fractional Shares shall be eliminated by rounding down.

(e)Notwithstanding any other provision of the Plan, unless otherwise determined by the Administrator or required by Applicable Law, the Company shall not deliver to any Holder certificates evidencing Shares issued in connection with any Award and instead such Shares shall be recorded in the books of the Company (or, as applicable, its transfer agent or stock plan administrator).

10.5Forfeiture and Claw-Back Provisions. Pursuant to its general authority to determine the terms and conditions applicable to Awards under the Plan, the Administrator shall have the right to provide, in an Award Agreement or otherwise, or to require a Holder to agree by separate written or electronic instrument, that:

(a)(i) Any proceeds, gains or other economic benefit actually or constructively received by the Holder upon any receipt or exercise of the Award, or upon the

21

receipt or resale of any Shares underlying the Award, shall be paid to the Company, and (ii) the Award shall terminate and any unexercised portion of the Award (whether or not vested) shall be forfeited, if (x) a Termination of Service occurs prior to a specified date, or within a specified time period following receipt or exercise of the Award, or (y) the Holder at any time, or during a specified time period, engages in any activity in competition with the Company, or which is inimical, contrary or harmful to the interests of the Company, as further defined by the Administrator or (z) the Holder incurs a Termination of Service for “cause” (as such term is defined in the discretion of the Administrator, or as set forth in a written agreement relating to such Award between the Company and the Holder); and

(b)All Awards (including any proceeds, gains or other economic benefit actually or constructively received by the Holder upon any receipt or exercise of any Award or upon the receipt or resale of any Shares underlying the Award) shall be subject to the provisions of any claw-back policy implemented by the Company, including, without limitation, any claw-back policy adopted to comply with the Dodd-Frank Wall Street Reform and Consumer Protection Act and any rules or regulations promulgated thereunder, to the extent set forth in such claw-back policy and/or in the applicable Award Agreement.

10.6Repricing. Subject to Section 12.2, the Administrator shall have the authority, without the approval of the stockholders of the Company, to amend any outstanding Option or Stock Appreciation Right to reduce its price per share or cancel any Option or Stock Appreciation Right in exchange for cash or another Award when the Option or Stock Appreciation Right price per share exceeds the Fair Market Value of the underlying Shares.

ARTICLE 11.

ADMINISTRATION

11.1Administrator. The Committee (or another committee or a subcommittee of the Board assuming the functions of the Committee under the Plan) shall administer the Plan (except as otherwise permitted herein) and, unless otherwise determined by the Board, shall consist solely of two or more Non-Employee Directors appointed by and holding office at the pleasure of the Board, each of whom is intended to qualify as both a “non-employee director” as defined by Rule 16b-3 of the Exchange Act or any successor rule and an “independent director” under the rules of any securities exchange or automated quotation system on which the Shares are listed, quoted or traded.  Notwithstanding the foregoing, any action taken by the Committee shall be valid and effective, whether or not members of the Committee at the time of such action are later determined not to have satisfied the requirements for membership set forth in this Section 11.1 or otherwise provided in any charter of the Committee. Except as may otherwise be provided in any charter of the Committee, appointment of Committee members shall be effective upon acceptance of appointment. Committee members may resign at any time by delivering written or electronic notice to the Board. Vacancies in the Committee may only be filled by the Board. Notwithstanding the foregoing, (a) the full Board, acting by a majority of its members in office, shall conduct the general administration of the Plan with respect to Awards granted to Non-Employee Directors and, with respect to such Awards, the terms “Administrator” and “Committee” as used in the Plan shall be deemed to refer to the Board and (b) the Board or Committee may delegate its authority hereunder to the extent permitted by Section 11.6.

22

11.2Duties and Powers of Committee. It shall be the duty of the Committee to conduct the general administration of the Plan in accordance with its provisions. The Committee shall have the power to interpret the Plan and Award Agreements, and to adopt such rules for the administration, interpretation and application of the Plan as are not inconsistent therewith, to interpret, amend or revoke any such rules and to amend any Award Agreement; provided that the rights or obligations of the Holder of the Award that is the subject of any such Award Agreement are not affected adversely by such amendment, unless the consent of the Holder is obtained or such amendment is otherwise permitted under Section 10.5 or Section 12.10. Any such grant or award under the Plan need not be the same with respect to each Holder. Any such interpretations and rules with respect to Incentive Stock Options shall be consistent with the provisions of Section 422 of the Code. In its discretion, the Board may at any time and from time to time exercise any and all rights and duties of the Committee under the Plan except with respect to matters which under Rule 16b-3 under the Exchange Act or any successor rule, or any regulations or rules issued thereunder, or the rules of any securities exchange or automated quotation system on which the Shares are listed, quoted or traded are required to be determined in the discretion of the Committee.

11.3Action by the Committee. Unless otherwise established by the Board or in any charter of the Committee, a majority of the Committee shall constitute a quorum and the acts of a majority of the members present at any meeting at which a quorum is present, and acts approved in writing by all members of the Committee in lieu of a meeting, shall be deemed the acts of the Committee. Each member of the Committee is entitled to, in good faith, rely or act upon any report or other information furnished to that member by any officer or other employee of the Company or any Subsidiary, the Company’s independent certified public accountants, or any executive compensation consultant or other professional retained by the Company to assist in the administration of the Plan.

11.4Authority of Administrator. Subject to the Company’s Bylaws, the Committee’s Charter and any specific designation in the Plan, the Administrator has the exclusive power, authority and sole discretion to:

(a)Designate Eligible Individuals to receive Awards;

(b)Determine the type or types of Awards to be granted to Eligible Individuals;

(c)Determine the number of Awards to be granted and the number of Shares to which an Award will relate;

(d)Determine the terms and conditions of any Award granted pursuant to the Plan, including, but not limited to, the exercise price, grant price, purchase price, any Performance Goals or Performance Criteria, any reload provision, any restrictions or limitations on the Award, any schedule for vesting, lapse of forfeiture restrictions or restrictions on the exercisability of an Award, and accelerations or waivers thereof, and any provisions related to non-competition and recapture of gain on an Award, based in each case on such considerations as the Administrator in its sole discretion determines;

23

(e)Determine whether, to what extent, and pursuant to what circumstances an Award may be settled in, or the exercise price of an Award may be paid in cash, Shares, other Awards, or other property, or an Award may be canceled, forfeited, or surrendered;

(f)Prescribe the form of each Award Agreement, which need not be identical for each Holder;

(g)Decide all other matters that must be determined in connection with an Award;

(h)Establish, adopt or revise any rules and regulations as it may deem necessary or advisable to administer the Plan;

(i)Interpret the terms of, and any matter arising pursuant to, the Plan or any Award Agreement;

(j)Make all other decisions and determinations that may be required pursuant to the Plan or as the Administrator deems necessary or advisable to administer the Plan; and

(k)Accelerate wholly or partially the vesting or lapse of restrictions of any Award or portion thereof at any time after the grant of an Award, subject to whatever terms and conditions it selects and Section 12.2(d).

11.5Decisions Binding. The Administrator’s interpretation of the Plan, any Awards granted pursuant to the Plan, and any Award Agreement and all decisions and determinations by the Administrator with respect to the Plan are final, binding and conclusive on all parties.

11.6Delegation of Authority. To the extent permitted by Applicable Law, the Board or Committee may from time to time delegate to a committee of one or more members of the Board or one or more officers of the Company the authority to grant or amend Awards or to take other administrative actions pursuant to this Article 11; provided, however, that in no event shall an officer of the Company be delegated the authority to grant awards to, or amend awards held by, the following individuals: (a) individuals who are subject to Section 16 of the Exchange Act or (b) officers of the Company (or Directors) to whom authority to grant or amend Awards has been delegated hereunder; provided, further, that any delegation of administrative authority shall only be permitted to the extent it is permissible under Applicable Law. Any delegation hereunder shall be subject to the restrictions and limits that the Board or Committee specifies at the time of such delegation, and the Board may at any time rescind the authority so delegated or appoint a new delegatee. At all times, the delegatee appointed under this Section 11.6 shall serve in such capacity at the pleasure of the Board and the Committee.

ARTICLE 12.

MISCELLANEOUS PROVISIONS

12.1Amendment, Suspension or Termination of the Plan. Except as otherwise provided in this Section 12.1, the Plan may be wholly or partially amended or otherwise modified, suspended or terminated at any time or from time to time by the Board or the

24

Committee. However, without approval of the Company’s stockholders given within twelve (12) months before or after the action by the Administrator, no action of the Administrator may, except as provided in Section 12.2, increase the limits imposed in Section 3.1 on the maximum number of Shares which may be issued under the Plan. Except as provided in Section 12.10, no amendment, suspension or termination of the Plan shall, without the consent of the Holder, impair any rights or obligations under any Award theretofore granted or awarded, unless the Award itself otherwise expressly so provides. No Awards may be granted or awarded during any period of suspension or after termination of the Plan, and in no event may any Award be granted under the Plan after the tenth (10th) anniversary of the date the Plan is first adopted by the Board (the “Expiration Date”). Any Awards that are outstanding on the Expiration Date shall remain in force according to the terms of the Plan and the applicable Award Agreement.

12.2Changes in Common Stock or Assets of the Company, Acquisition or Liquidation of the Company and Other Corporate Events.

(a)In the event of any stock dividend, stock split, combination or exchange of shares, merger, consolidation or other distribution (other than normal cash dividends) of Company assets to stockholders, or any other change affecting the shares of the Company’s stock or the share price of the Company’s stock other than an Equity Restructuring, the Administrator may make equitable adjustments, if any, to reflect such change with respect to: (i) the aggregate number and kind of shares that may be issued under the Plan (including, but not limited to, adjustments of the limitations in Sections 3.1 and 3.3 on the maximum number and kind of shares which may be issued under the Plan); (ii) the number and kind of Shares (or other securities or property) subject to outstanding Awards; (iii) the number and kind of Shares (or other securities or property) for which automatic grants are subsequently to be made to new and continuing Non-Employee Directors pursuant to Section 4.5; (iv) the terms and conditions of any outstanding Awards (including, without limitation, any applicable performance targets or criteria with respect thereto); and (v) the grant or exercise price per share for any outstanding Awards under the Plan.

(b)In the event of any transaction or event described in Section 12.2(a) or any unusual or nonrecurring transactions or events affecting the Company, any Subsidiary of the Company, or the financial statements of the Company or any Subsidiary, or of changes in Applicable Law or accounting principles, the Administrator, in its discretion, and on such terms and conditions as it deems appropriate, either by the terms of the Award or by action taken prior to the occurrence of such transaction or event and either automatically or upon the Holder’s request, is hereby authorized to take any one or more of the following actions whenever the Administrator determines that such action is appropriate in order to prevent dilution or enlargement of the benefits or potential benefits intended to be made available under the Plan or with respect to any Award under the Plan, to facilitate such transactions or events or to give effect to such changes in laws, regulations or principles:

(i)To provide for either (A) termination of any such Award in exchange for an amount of cash, if any, equal to the amount that would have been attained upon the exercise of such Award or realization of the Holder’s rights (and, for the avoidance of doubt, if as of the date of the occurrence of the transaction or event described in this Section 12.2 the Administrator determines in good faith that no amount would have been attained upon the

25

exercise of such Award or realization of the Holder’s rights, then such Award may be terminated by the Company without payment) or (B) the replacement of such Award with other rights or property selected by the Administrator, in its discretion, having an aggregate value not exceeding the amount that could have been attained upon the exercise of such Award or realization of the Holder’s rights had such Award been currently exercisable or payable or fully vested;

(ii)To provide that such Award be assumed by the successor or survivor corporation, or a parent or subsidiary thereof, or shall be substituted for by similar options, rights or awards covering the stock of the successor or survivor corporation, or a parent or subsidiary thereof, with appropriate adjustments as to the number and kind of shares and prices;

(iii)To make adjustments in the number and type of shares of the Company’s stock (or other securities or property) subject to outstanding Awards, and in the number and kind of outstanding Restricted Stock and/or in the terms and conditions of (including the grant or exercise price), and the criteria included in, outstanding Awards and Awards which may be granted in the future;

(iv)To provide that such Award shall be exercisable or payable or fully vested with respect to all shares covered thereby, notwithstanding anything to the contrary in the Plan or the applicable Award Agreement; and

(v)To provide that the Award cannot vest, be exercised or become payable after such event.

(c)In connection with the occurrence of any Equity Restructuring, and notwithstanding anything to the contrary in Section 12.2(a) and 12.2(b), the Administrator shall equitably adjust each outstanding Award, which adjustments may include adjustments to the number and type of securities subject to each outstanding Award and/or the exercise price or grant price thereof, if applicable, the grant of new Awards to Participants, and/or the making of a cash payment to Participants, as the Administrator deems appropriate to reflect such Equity Restructuring. The adjustments provided under this Section 12.2(c) shall be nondiscretionary and shall be final and binding on the affected Holder and the Company; provided that whether an adjustment is equitable shall be determined in the discretion of the Administrator.

(d)Notwithstanding any other provision of the Plan, in the event of a Change in Control, each outstanding Award shall continue in effect or be assumed or an equivalent Award substituted by the successor corporation or a parent or subsidiary of the successor corporation.

(e)In the event that the successor corporation in a Change in Control refuses to assume or substitute for an Award, the Administrator may cause all or any portion of such Award to become fully exercisable immediately prior to the consummation of such transaction and all forfeiture restrictions on all or any portion of such Award to lapse. If an Award is exercisable in lieu of assumption or substitution in the event of a Change in Control, the Administrator shall notify the Holder that the Award shall be fully exercisable for a period of

26

fifteen (15) days from the date of such notice, contingent upon the occurrence of the Change in Control, and the Award shall terminate upon the expiration of such period.

(f)For the purposes of this Section 12.2, an Award shall be considered assumed if, following the Change in Control, the Award confers the right to purchase or receive, for each Share subject to the Award immediately prior to the Change in Control, the consideration (whether stock, cash, or other securities or property) received in the Change in Control by holders of Common Stock for each Share held on the effective date of the transaction (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of the outstanding Shares); provided, however, that if such consideration received in the Change in Control was not solely common stock of the successor corporation or its parent, the Administrator may, with the consent of the successor corporation, provide for the consideration to be received upon the exercise of the Award, for each Share subject to an Award, to be solely common stock of the successor corporation or its parent equal in fair market value to the per-share consideration received by holders of Common Stock in the Change in Control.

(g)The Administrator, in its discretion, may include such further provisions and limitations in any Award, agreement or certificate, as it may deem equitable and in the best interests of the Company that are not inconsistent with the provisions of the Plan.

(h)No adjustment or action described in this Section 12.2 or in any other provision of the Plan shall be authorized to the extent that such adjustment or action would cause the Plan to violate Section 422(b)(1) of the Code. Furthermore, no such adjustment or action shall be authorized to the extent such adjustment or action would result in short-swing profits liability under Section 16 or violate the exemptive conditions of Rule 16b-3 unless the Administrator determines that the Award is not to comply with such exemptive conditions.

(i)The existence of the Plan, the Award Agreement and the Awards granted hereunder shall not affect or restrict in any way the right or power of the Company or the stockholders of the Company to make or authorize any adjustment, recapitalization, reorganization or other change in the Company’s capital structure or its business, any merger or consolidation of the Company, any issue of stock or of options, warrants or rights to purchase stock or of bonds, debentures, preferred or prior preference stocks whose rights are superior to or affect the Common Stock or the rights thereof or which are convertible into or exchangeable for Common Stock, or the dissolution or liquidation of the Company, or any sale or transfer of all or any part of its assets or business, or any other corporate act or proceeding, whether of a similar character or otherwise.

(j)No action shall be taken under this Section 12.2 which shall cause an Award to fail to comply with Section 409A of the Code, to the extent applicable the Award.

(k)In the event of any pending stock dividend, stock split, combination or exchange of shares, merger, consolidation or other distribution (other than normal cash dividends) of Company assets to stockholders, or any other change affecting the Shares or the share price of the Common Stock including any Equity Restructuring, for reasons of administrative convenience, the Company, in its discretion, may refuse to permit the exercise of

27

any Award during a period of up to thirty (30) days prior to the consummation of any such transaction.

12.3Approval of Plan by Stockholders. The Plan shall be submitted for the approval of the Company’s stockholders within twelve (12) months after the date of the Board’s initial adoption of the Plan.

12.4No Stockholders Rights. Except as otherwise provided herein, a Holder shall have none of the rights of a stockholder with respect to Shares covered by any Award until the Holder becomes the record owner of such Shares.

12.5Paperless Administration. In the event that the Company establishes, for itself or using the services of a third party, an automated system for the documentation, granting or exercise of Awards, such as a system using an internet website or interactive voice response, then the paperless documentation, granting or exercise of Awards by a Holder may be permitted through the use of such an automated system.

12.6Effect of Plan upon Other Compensation Plans. The adoption of the Plan shall not affect any other compensation or incentive plans in effect for the Company or any Subsidiary. Nothing in the Plan shall be construed to limit the right of the Company or any Subsidiary: (a) to establish any other forms of incentives or compensation for Employees, Directors or Consultants of the Company or any Subsidiary, or (b) except as otherwise provided in the penultimate sentence of Section 3.1(a), to grant or assume options or other rights or awards otherwise than under the Plan in connection with any proper corporate purpose including without limitation, the grant or assumption of options in connection with the acquisition by purchase, lease, merger, consolidation or otherwise, of the business, stock or assets of any corporation, partnership, limited liability company, firm or association.

12.7Compliance with Laws. The Plan, the granting and vesting of Awards under the Plan and the issuance and delivery of Shares and the payment of money under the Plan or under Awards granted or awarded hereunder are subject to compliance with all Applicable Law (including but not limited to state, federal and foreign securities law and margin requirements), and to such approvals by any listing, regulatory or governmental authority as may, in the opinion of counsel for the Company, be necessary or advisable in connection therewith. Any securities delivered under the Plan shall be subject to such restrictions, and the person acquiring such securities shall, if requested by the Company, provide such assurances and representations to the Company as the Company may deem necessary or desirable to assure compliance with all Applicable Law. To the extent permitted by Applicable Law, the Plan and Awards granted or awarded hereunder shall be deemed amended to the extent necessary to conform to Applicable Law.

12.8Titles and Headings, References to Sections of the Code or Exchange Act. The titles and headings of the Sections in the Plan are for convenience of reference only and, in the event of any conflict, the text of the Plan, rather than such titles or headings, shall control. References to sections of the Code or the Exchange Act shall include any amendment or successor thereto.

28

12.9Governing Law. The Plan and any agreements hereunder shall be administered, interpreted and enforced under the internal laws of the State of Delaware without regard to conflicts of laws thereof or of any other jurisdiction.

12.10Section 409A. To the extent that the Administrator determines that any Award granted under the Plan is subject to Section 409A of the Code, the Award Agreement evidencing such Award shall incorporate the terms and conditions required by Section 409A of the Code. To the extent applicable, the Plan and any Award Agreements shall be interpreted in accordance with Section 409A of the Code, including without limitation any such regulations or other guidance that may be issued after the Effective Date. Notwithstanding any provision of the Plan to the contrary, in the event that following the Effective Date the Administrator determines that any Award may be subject to Section 409A of the Code (including Department of Treasury guidance as may be issued after the Effective Date), the Administrator may adopt such amendments to the Plan and the applicable Award Agreement or adopt other policies and procedures (including amendments, policies and procedures with retroactive effect), or take any other actions, that the Administrator determines are necessary or appropriate to (a) exempt the Award from Section 409A of the Code and/or preserve the intended tax treatment of the benefits provided with respect to the Award, or (b) comply with the requirements of Section 409A of the Code and thereby avoid the application of any penalty taxes under such Section.

12.11No Rights to Awards. No Eligible Individual or other person shall have any claim to be granted any Award pursuant to the Plan, and neither the Company nor the Administrator is obligated to treat Eligible Individuals, Holders or any other persons uniformly.

12.12Unfunded Status of Awards. The Plan is intended to be an “unfunded” plan for incentive compensation. With respect to any payments not yet made to a Holder pursuant to an Award, nothing contained in the Plan or any Award Agreement shall give the Holder any rights that are greater than those of a general creditor of the Company or any Subsidiary.

12.13Indemnification. To the extent allowable pursuant to Applicable Law, each member of the Committee or of the Board shall be indemnified and held harmless by the Company from any loss, cost, liability, or expense that may be imposed upon or reasonably incurred by such member in connection with or resulting from any claim, action, suit, or proceeding to which he or she may be a party or in which he or she may be involved by reason of any action or failure to act pursuant to the Plan and against and from any and all amounts paid by him or her in satisfaction of judgment in such action, suit, or proceeding against him or her; provided he or she gives the Company an opportunity, at its own expense, to handle and defend the same before he or she undertakes to handle and defend it on his or her own behalf. The foregoing right of indemnification shall not be exclusive of any other rights of indemnification to which such persons may be entitled pursuant to the Company’s Certificate of Incorporation or Bylaws, as a matter of law, or otherwise, or any power that the Company may have to indemnify them or hold them harmless.

12.14Section 83(b) Election.  No Participant may make an election under Section 83(b) of the Code with respect to any Award under the Plan without the consent of the Company, which the Company may grant or withhold in its sole discretion.  If, with the consent of the Company, a Participant makes an election under Section 83(b) of the Code, the Participant shall

29

be required to deliver a copy of such election to the Company promptly after filing such election with the Internal Revenue Service.

12.15Relationship to other Benefits. No payment pursuant to the Plan shall be taken into account in determining any benefits under any pension, retirement, savings, profit sharing, group insurance, welfare or other benefit plan of the Company or any Subsidiary except to the extent otherwise expressly provided in writing in such other plan or an agreement thereunder.

12.16Expenses. The expenses of administering the Plan shall be borne by the Company and its Subsidiaries.

* * * * *

30

EX-10.9

Exhibit 10.9

FORM OF STOCKHOLDERS AGREEMENT

STOCKHOLDERS AGREEMENT (this “Agreement”), dated as of                     , 2013, by and among ATHLON ENERGY INC., a Delaware corporation (the “Corporation”), and those stockholders of the Corporation listed on Schedule A hereto.

WHEREAS, the Corporation, the Apollo Entities (as defined below) and the Employee Stockholders (as defined below), as the holders of the majority shares of Stock (as defined below) owned by the stockholders of the Corporation listed on Schedule A hereto wish to enter into this Agreement in accordance with the terms set forth herein.

NOW, THEREFORE, in consideration of the promises and of the mutual consents and obligations hereinafter set forth, the parties hereto hereby agree as follows:

Section 1               Definitions; Interpretation.

(a)           Definitions.  As used herein, the following terms shall have the following respective meanings:

“Adoption” has the meaning set forth in Exhibit A.

“Affiliate” means (a) as to any Person, other than an individual, any other Person or entity who directly, or indirectly through one or more intermediaries, controls, is controlled by or is under common control with such Person and (b) as to any individual, in addition to any Person in clause (a), (i) any member of the immediate family of an individual Stockholder, including parents, siblings, spouse and children (including those by adoption), the parents, siblings, spouse, or children (including those by adoption) of such immediate family member, and, in any such case, any trust whose primary beneficiary is such individual Stockholder or one or more members of such immediate family and/or such Stockholder’s lineal descendants, (ii) the legal representative or guardian of such individual Stockholder or of any such immediate family member in the event such individual Stockholder or any such immediate family member becomes mentally incompetent and (iii) any Person controlling, controlled by or under common control with a Stockholder; provided that the term “Affiliate” shall not include at any time any portfolio companies of Apollo. As used in this definition, the term “control,” including the correlative terms “controlling,” “controlled by” and “under common control with,” means possession, directly or indirectly, of the power to direct or cause the direction of management or policies (whether through ownership of securities or any partnership or other ownership interest, by contract or otherwise) of a Person.

“Agreement” has the meaning set forth in the Preamble.

“Apollo” means, collectively, Apollo Investment Fund VII, L.P. and its parallel funds.

“Apollo Demand Notice” has the meaning set forth in Section 3(a).

“Apollo Entities” means Apollo, Apollo Athlon Holdings, L.P., AP Overseas VII (Athlon FC) Holdings, L.P. and each of their respective Affiliates.

“Apollo Registration Demand” has the meaning set forth in Section 3(a).

“Apollo Stockholder” means any Apollo Entity that owns any shares of Stock in the Corporation.

“Board” means the board of directors of the Corporation.

“Business Day” means a day that is not a Saturday, Sunday or day on which banking institutions in the city to which the notice or communication is to be sent are not required to be open.

“Common Stock” means the common stock, par value $0.01 per share, of the Corporation and any stock into which such Stock may hereafter be changed or for which such Common Stock may be exchanged, and shall also include any Common Stock of the Corporation of any class hereafter authorized.

“Control Disposition” means a Disposition by the Apollo Entities that would have the effect of transferring to a Person or Group that is not an Affiliate of the Apollo Entities or a portfolio company of one or more Apollo Entities or Affiliates thereof a number of shares of Common Stock such that, following the consummation of such Disposition, such Person or Group possesses the voting power to elect a majority of the Board (whether by merger, consolidation, sale or transfer of Common Stock or otherwise) or a majority of the board of directors (or similar body) of any successor entity.

“Corporation” has the meaning set forth in the Preamble.

“Corporation Registration” has the meaning set forth in Section 4(a).

“Corporation Securities” has the meaning set forth in Section 4(c)(i).

“Demand Notice” has the meaning set forth in Section 3(b).

“Disposition” (including, with correlative meaning, the term “Dispose”) means (a) any direct or indirect transfer, assignment, sale, gift, pledge, hypothecation or other encumbrance, or any other disposition, of Common Stock (or any interest therein or right thereto) or of all or part of the voting power (other than the granting of a revocable proxy) associated with the Common Stock (or any interest therein) whatsoever, or any other transfer of beneficial ownership of Common Stock, whether voluntary or involuntary.

“Employee Stockholder” means each of the Stockholders who is executing this Agreement, who is at the time of such execution an employee of, or who serves at the time of such execution as a consultant to or director of, the Corporation or its Subsidiaries or Affiliates.

“Employee Stockholder Registration Demand” has the meaning set forth in Section 3(a).

“Exchange Agreement” means that Exchange Agreement, dated                       , 2013, among the Partnership, the Corporation and certain holders of limited partner interests in the Partnership.

2

“Group” has the meaning set forth in Section 13(d)(3) of the Securities Exchange Act.

“Indemnified Party” has the meaning set forth in Section 5(c).

“Indemnifying Party” has the meaning set forth in Section 5(c).

“IPO” means an initial public offering of the shares of Common Stock in a firm commitment underwriting effected by the Corporation pursuant to a Registration Statement.

“Losses” has the meaning set forth in Section 5(a).

“Partnership” means Athlon Holdings LP, a Delaware limited partnership.

“Person” means any natural person, corporation, partnership, limited liability company, firm, association, trust, government, governmental agency or other entity, whether acting in an individual, fiduciary or other capacity.

“Registrable Securities” means shares of Common Stock and any shares of Common Stock which were acquired by a Stockholder as of the date of this Agreement; provided that any Registrable Security will cease to be a Registrable Security when (a) a Registration Statement covering such Registrable Security has been declared effective by the SEC and such Registrable Security has been disposed of pursuant to such effective Registration Statement, (b) it is sold under circumstances in which all of the applicable conditions of Rule 144 (or any similar provisions then in force) under the Securities Act are met or it is eligible for sale under such Rule 144, not taking into account any volume limitations or (c) it shall have been otherwise transferred and a new certificate for it not bearing a legend restricting further transfer under the Securities Act shall have been delivered by the Corporation; provided, further, that any security that has ceased to be a Registrable Security shall not thereafter become a Registrable Security and any security that is issued or distributed in respect of securities that have ceased to be Registrable Securities is not a Registrable Security.

“Registration Expenses” means all expenses incurred by the Corporation in complying with Section 4, including, without limitation, all registration and filing fees, printing expenses, road show expenses, fees and disbursements of counsel and independent public accountants for the Corporation, fees and expenses (including counsel fees) incurred in connection with complying with state securities or “blue sky” laws, fees of the Financial Industry Regulatory Authority, Inc., transfer taxes, fees of transfer agents and registrars, and the reasonable fees and disbursements of one counsel for the selling holders of Registrable Securities, but excluding any underwriting discounts and selling commissions only to the extent applicable on a per share basis to Registrable Securities of the selling holders.

“Registration Statement” means any registration statement of the Corporation filed or to be filed with the SEC under the rules and regulations promulgated under the Securities Act, including the related prospectus, amendments and supplements to such registration statement, and including pre- and post-effective amendments, and all exhibits and all material incorporated by reference in such registration statement.

“Representative” has the meaning set forth in Section 9(a).

3

“SEC” means the Securities and Exchange Commission or any successor governmental agency.

“Section 4(c) Sale Number” has the meaning set forth in Section 4(c).

“Section 4(d) Sale Number” has the meaning set forth in Section 4(d).

“Securities Act” means the Securities Act of 1933, as amended, or any successor federal statute, and the rules and regulations of the SEC thereunder, all as the same shall be in effect at the time.

“Securities Exchange Act” means the Securities Exchange Act of 1934, as amended, or any successor federal statute, and the rules and regulations of the SEC thereunder, all as the same shall be in effect at the time.

“Senior Management” has the meaning set forth in Section 9(a).

“Stock” means (i) the outstanding shares of Common Stock of the Corporation, (ii) any additional shares of Common Stock of the Corporation that may be issued in the future and (iii) any shares of capital stock of the Corporation into which such shares may be converted or for which they may be exchanged.

“Stockholder Registration” has the meaning set forth in Section 4(a).

“Stockholders” means those Persons identified on the signature pages hereto as the Stockholders and shall include any other Person who agrees in writing with the parties hereto to be bound by and to comply with all the provisions of this Agreement applicable to a Stockholder, including any Person who becomes a party to this Agreement by executing an Adoption Agreement substantially in the form of Exhibit A or in such other form as is reasonably satisfactory to the Corporation.

“Subsidiary” means, with respect to any Person, any corporation, limited liability company, partnership, joint venture or other legal entity of which such Person (either above or through or together with any other Subsidiary) owns, directly or indirectly, more than 50% of the stock or other equity interests the holders of which are generally entitled to vote for the election of the board of directors or other governing body of such corporation or other legal entity.

“Underwritten Offering” means a sale of shares of Common Stock to an underwriter for reoffering to the public.

Any capitalized term used in any Section of this Agreement that is not defined in this Section 1 shall have the meaning ascribed to it in such other Section.

(b)           Rules of Construction.  For all purposes of this Agreement, unless otherwise expressly provided:

(i)            “own,” “ownership,” “held” and “holding” refer to ownership or holding as record holder or record owner;

4

(ii)           the headings and captions of this Agreement are for convenience of reference only and shall not define, limit or otherwise affect any of the terms hereof; and

(iii)          whenever the context requires, the gender of all words used herein shall include the masculine, feminine and neuter, and the number of all words shall include the singular and plural.

Section 2               Securities Restrictions; Apollo Transfers.

(a)           Securities Restrictions.

(i)            Notwithstanding any other provision of this Agreement, no shares of Common Stock covered by this Agreement shall be transferable except upon the conditions specified in this Section 2(a), which conditions are intended to ensure compliance with the provisions of the Securities Act.

(ii)           Each certificate or book-entry notation representing shares of Common Stock covered by this Agreement shall (unless otherwise permitted by the provisions of paragraph (iv) of this Section 2(a)) be stamped or otherwise imprinted with a legend in substantially the form provided in Section 12.

(iii)          The holder of any shares of Common Stock covered by this Agreement agrees, prior to any transfer of any such shares, to give written notice to the Corporation of such holder’s intention to effect such transfer and to comply in all other respects with the provisions of this Section 2(a).  Each such notice shall describe the manner and circumstances of the proposed transfer.  Upon request by the Corporation, the holder delivering such notice shall deliver a written opinion, addressed to the Corporation, of counsel for the holder of such shares, stating that in the opinion of such counsel (which opinion and counsel shall be reasonably satisfactory to the Corporation) such proposed transfer does not involve a transaction requiring registration or qualification of such shares under the Securities Act.  Such holder of such shares shall be entitled to transfer such shares in accordance with the terms of the notice delivered to the Corporation, if the Corporation does not reasonably object to such transfer and request such opinion within fourteen (14) Business Days after delivery of such notice, or, if it requests such opinion, does not reasonably object to such transfer within fourteen (14) Business Days after delivery of such opinion.  Subject to paragraph (iv) of this Section 2(a), each certificate or other instrument evidencing any such transferred shares of Common Stock shall bear the legend required by paragraph (ii) of this Section 2(a) unless (A) such opinion of counsel to the holder of such shares (which opinion and counsel shall be reasonably acceptable to the Corporation) states that registration of any future transfer is not required by the applicable provisions of the Securities Act or (B) the Corporation shall have waived the requirement of such legend, which waiver may or may not be given in the Corporation’s absolute discretion.

5

(iv)          Notwithstanding the foregoing provisions of this Section 2(a), the restrictions imposed by this Section 2(a) upon the transferability of any shares of Common Stock covered by this Agreement shall cease and terminate when (A) any such shares are sold or otherwise disposed of pursuant to an effective Registration Statement under the Securities Act or (B) the holder of such shares has met the requirements for transfer of such shares pursuant to Rule 144 under the Securities Act.  Whenever the restrictions imposed by this Section 2(a) shall terminate, the holder of any shares as to which such restrictions have terminated shall be entitled to receive from the Corporation, without expense, a new certificate (or book-entry notation) not bearing the restrictive legend set forth in Section 12 and not containing any other reference to the restrictions imposed by this Section 2(a).

(b)           Apollo Transfers.  In the event that any Person that is an Affiliate of the Apollo Entities acquires shares of Common Stock from the Apollo Stockholders or any other Affiliate of the Apollo Entities, such Person shall be subject to and have the benefit of any and all rights, obligations and restrictions of the Apollo Entities hereunder, as if such Person were an Apollo Entity.

Section 3               Demand Registration Rights.

(a)           Apollo Registration Rights.  Subject to the provisions of this Section 3, at any time and from time to time after the date of this Agreement, Apollo may make one or more written demands (each, an “Apollo Registration Demand”) to the Corporation requiring the Corporation to register, under and in accordance with the provisions of the Securities Act, all or part of the Apollo Stockholders’ shares of Common Stock.  All Apollo Registration Demands made pursuant to this Section 3 will specify the aggregate amount of shares of Common Stock to be registered, the intended methods of disposition thereof (including whether the offering is to be an Underwritten Offering) and the registration procedures to be undertaken by the Corporation in connection therewith (an “Apollo Demand Notice”).  Subject to Section 3(b), promptly upon receipt of any such Apollo Demand Notice, the Corporation will file the applicable Registration Statement as soon as reasonably practicable and will use its best efforts to, in accordance with the terms set forth in the Apollo Demand Notice, effect within one hundred eighty (180) days of the filing of such Registration Statement the registration under the Securities Act (including, without limitation, appropriate qualification under applicable blue sky or other state securities laws and appropriate compliance with the applicable regulations promulgated under the Securities Act) of the shares of Common Stock that the Corporation has been so required to register.

(b)           Employee Stockholder Registration Rights.  Subject to the provisions of this Section 3 and the Contribution and Exchange Agreement, dated as of April 26, 2013, by and among the Class B limited partners of the Partnership and the Corporation, at any time and from time to time after the date of this Agreement, so long as the Employee Stockholders collectively own at least 1% of the outstanding Common Stock, the Employee Stockholders may make one or more written demands (each, an “Employee Stockholder Registration Demand” and, together with an Apollo Registration Demand, a

6

“Registration Demand”) to the Corporation requiring the Corporation to register, under and in accordance with the provisions of the Securities Act, all or part of the Employee Stockholders’ shares of Common Stock.  All Employee Stockholder Registration Demands made pursuant to this Section 3 will specify the aggregate amount of shares of Common Stock to be registered, the intended methods of disposition thereof (including whether the offering is to be an Underwritten Offering) and the registration procedures to be undertaken by the Corporation in connection therewith (an “Employee Stockholder Demand Notice” and, together with an Apollo Demand Notice, a “Demand Notice”).  Subject to Section 3(c), promptly upon receipt of any such Employee Stockholder Demand Notice, the Corporation will file the applicable Registration Statement as soon as reasonably practicable and will use its best efforts to, in accordance with the terms set forth in the Employee Stockholder Demand Notice, effect within one hundred eighty (180) days of the filing of such Registration Statement the registration under the Securities Act (including, without limitation, appropriate qualification under applicable blue sky or other state securities laws and appropriate compliance with the applicable regulations promulgated under the Securities Act) of the shares of Common Stock that the Corporation has been so required to register.

(c)           Registration Obligations and Procedures.

(i)            If the Corporation receives a Registration Demand and the Corporation furnishes to Apollo or the Employee Stockholders (each, a “Requesting Stockholder”) a copy of a resolution of the Board certified by the secretary of the Corporation stating that in the good faith judgment of the Board it would be materially adverse to the Corporation for a Registration Statement to be filed on or before the date such filing would otherwise be required hereunder, the Corporation shall have the right to defer such filing for a period of not more than sixty (60) days after receipt of the Demand Notice for such registration from the Requesting Stockholder. The Corporation shall not be permitted to provide such notice more than twice in any three hundred sixty (360) day period.  If the Corporation shall so postpone the filing of a Registration Statement, the Requesting Stockholder may withdraw the Registration Demand by so advising the Corporation in writing within thirty (30) days after receipt of the notice of postponement.  In addition, if the Corporation receives a Registration Demand and the Corporation is then in the process of preparing to engage in a public offering, the Corporation shall inform the Requesting Stockholder of the Corporation’s intent to engage in a public offering and may require the Requesting Stockholder to withdraw such Registration Demand for a period of up to one hundred twenty (120) days so that the Corporation may complete its public offering.  In the event that the Corporation ceases to pursue such public offering, it shall promptly inform the Requesting Stockholder, and the Requesting Stockholder shall be permitted to submit a new Registration Demand.  For the avoidance of doubt, the Requesting Stockholders shall have the right to participate in the Corporation’s public offering as provided in Section 4.

(ii)           Registrations under this Section 3 shall be on such appropriate registration form of the SEC (A) as shall be selected by the Corporation and as

7

shall be reasonably acceptable to the Requesting Stockholder, and (B) as shall permit the disposition of such shares in accordance with the intended method or methods of disposition specified in the Demand Notice.  If, in connection with any registration under this Section 3 that is proposed by the Corporation to be on Form S-3 or any successor form, the managing underwriter, if any, shall advise the Corporation in writing that in its opinion the use of another permitted form is of material importance to the success of the offering, then such registration shall be on such other permitted form.

(iii)          The Corporation shall use its best efforts to keep any Registration Statement filed in response to a Registration Demand effective for as long as is necessary for the Requesting Stockholders to dispose of the covered securities.

(iv)          In the case of an Underwritten Offering in connection with a Registration Demand, the Requesting Stockholders shall select the underwriters, provided that the managing underwriter shall be a nationally recognized investment banking firm.  The Requesting Stockholders shall determine the pricing of the Registrable Securities offered pursuant to any such Registration Statement in connection with a Registration Demand, the applicable underwriting discount and other financial terms (including the material terms of the applicable underwriting agreement) and determine the timing of any such registration and sale, subject to Section 3(c)(i), and the Requesting Stockholders shall be solely responsible for all such discounts and fees payable to such underwriters in such Underwritten Offering.

(d)           No Inconsistent Agreements.  The Corporation represents and warrants that it has not granted and is not a party to any proxy, voting trust or other agreement that is inconsistent with or conflicts with this Section 3.  Other than the underwriting agreement entered into in connection with the IPO, the Corporation shall not hereafter enter into any agreement with respect to its securities that is inconsistent with or conflicts with the rights granted under this Section 3.

Section 4               Piggyback Registration Rights.

(a)           Piggyback Rights.  Subject to Section 4(c), and except in connection with the IPO (for which this Section 4(a) shall not apply), if the Corporation at any time proposes to register any Stock for its own account (a “Corporation Registration”) or for the account of any Stockholder possessing demand rights (including, for the avoidance of doubt, in connection with a Registration Demand) (a “Stockholder Registration”) under the Securities Act by registration on Form S-1 or Form S-3 or any successor or similar form(s) (except registrations on any such Form or similar form(s) solely for registration of securities in connection with an employee benefit plan, a dividend reinvestment plan or a merger or consolidation, or incidental to an issuance of securities under Rule 144A under the Securities Act), it will at such time give prompt written notice to the Stockholders of its intention to do so, including the anticipated filing date of the Registration Statement and, if known, the number of shares of Stock that are proposed to be included in such Registration Statement, and of the Stockholders’ rights under this

8

Section 4. Upon the written request of a Stockholder (which request shall specify the maximum number of Registrable Securities intended to be disposed of by such Stockholder and such other information as is reasonably required to effect the registration of such shares of Stock), made as promptly as practicable and in any event within fourteen (14) Business Days after the receipt of any such notice (five (5) Business Days if the Corporation states in such written notice or gives telephonic notice to such Stockholder, with written confirmation to follow promptly thereafter, stating that (i) such registration will be on Form S-3 and (ii) such shorter period of time is required because of a planned filing date), the Corporation, subject to Section 4(c), shall use its commercially reasonable efforts to effect the registration under the Securities Act of all Registrable Securities which the Corporation has been so requested to register by the Stockholders; provided, however, that if, at any time after giving written notice of its intention to register any securities and prior to the effective date of the Registration Statement filed in connection with such registration, the Corporation shall determine for any reason not to register or to delay registration of such securities, the Corporation shall give written notice of such determination to the Stockholders requesting registration under this Section 4 (which such Stockholders will hold in strict confidence) and (i) in the case of a determination not to register, shall be relieved of its obligation to register any Registrable Securities in connection with such registration (but not from any obligation of the Corporation to pay the Registration Expenses in connection therewith), and (ii) in the case of a determination to delay registering, shall be permitted to delay registering any Registrable Securities, for the same period as the delay in registering such other securities.

(b)           Stockholder Withdrawal.  Each Stockholder shall have the right to withdraw its request for inclusion of its Registrable Securities in any Registration Statement pursuant to this Section 4 at any time prior to the execution of an underwriting agreement with respect thereto by giving written notice to the Corporation of its request to withdraw.

(c)           Corporation Registration Underwriters’ Cutback.  In the case of a Corporation Registration, if the managing underwriter of any underwritten offering shall inform the Corporation by letter of its belief that the number of Registrable Securities requested to be included in such registration pursuant to this Section 4, when added to the number of other securities to be offered in such registration by the Corporation, would materially adversely affect such offering, then the Corporation shall include in such registration, to the extent of the total number of securities which the Corporation is so advised can be sold in (or during the time of) such offering without so materially adversely affecting such offering (the “Section 4(c) Sale Number”), securities in the following priority:

(i)            First, all Common Stock or securities convertible into, or exchangeable or exercisable for, Common Stock that the Corporation proposes to register for its own account (the “Corporation Securities”); and

(ii)           Second, to the extent that the number of Corporation Securities to be included is less than the Section 4(c) Sale Number, the Registrable Securities

9

requested to be included by the Stockholders; the securities requested to be included pursuant to this Section 4(c)(ii) shall be included on a pro rata basis based on the number of Registrable Securities subject to registration rights owned by each holder requesting inclusion in relation to the number of Registrable Securities then owned by all holders requesting inclusion, provided that the number of Registrable Securities owned by such Stockholders shall not include shares underlying any unvested options.

(d)           Stockholder Registration Underwriters’ Cutback.  In the case of a Stockholder Registration, if the managing underwriter of any underwritten offering shall inform the Corporation by letter of its belief that the number of shares of Common Stock and Registrable Securities requested to be included in such registration would materially adversely affect such offering, then the Corporation shall include in such registration, to the extent of the total number of securities which the Corporation is so advised can be sold in (or during the time of) such offering without so materially adversely affecting such offering (subject to the last paragraph of this Section 4(d), the “Section 4(d) Sale Number”), securities in the following priority:

(i)            First, the Registrable Securities requested to be included by the Persons exercising demand rights in connection with such Stockholder Registration; and

(ii)           Second, to the extent that the number of securities to be included in the registration pursuant to Section 4(d)(i) is less than the Section 4(d) Sale Number, the Registrable Securities requested to be included by the Stockholders exercising piggyback rights pursuant to this Section 4; the securities requested to be included pursuant to this Section 4(d)(ii) shall be included on a pro rata basis based on the number of Registrable Securities subject to registration rights owned by each holder requesting inclusion in relation to the number of Registrable Securities then owned by all holders requesting inclusion, provided that the number of Registrable Securities owned by such Stockholders shall not include any shares underlying options.

Notwithstanding anything to the contrary set forth in this Section 4(d), in connection with a Stockholder Registration pursuant to an Apollo Registration Demand, Apollo shall be entitled to determine, in its sole discretion, the Section 4(d) Sale Number applicable to such registration.

(e)           Participation in Underwritten Offerings.

(i)            Any participation by the Stockholders in a registration by the Corporation shall be in accordance with the plan of distribution of the Corporation (subject, in the case of a Stockholder Registration pursuant to an Apollo Registration Demand, to the rights of Apollo in Section 3(a)).  Except as provided in Section 3(c), in all Underwritten Offerings, the Corporation shall have sole discretion to select the underwriters.

10

(ii)           If the Corporation at any time shall register shares of Stock for its own account under the Securities Act for sale to the public, no Employee Stockholder shall sell publicly, make any short sale of, grant any option for the purchase of or otherwise dispose publicly of any capital stock of the Corporation without the prior written consent of the Corporation for the period of time in which the Apollo Stockholders have similarly agreed not to sell publicly, make any short sale of, grant any option for the purchase of or otherwise dispose publicly of any capital stock of the Corporation.

(iii)          In connection with any proposed registered offering of securities of the Corporation in which any Stockholder has the right to include Registrable Securities pursuant to this Section 4, such Stockholder agrees (A) to supply any information reasonably requested by the Corporation in connection with the preparation of a Registration Statement and/or any other documents relating to such registered offering and (B) to execute and deliver any agreements and instruments being executed by all holders on substantially the same terms reasonably requested by the Corporation to effectuate such registered offering, including, without limitation, underwriting agreements, custody agreements, lock-ups, “hold back” agreements pursuant to which such Stockholder agrees not to sell or purchase any securities of the Corporation for the same period of time following the registered offering as is agreed to by the other participating holders, powers of attorney and questionnaires.

(iv)          If the Corporation requests that the Stockholders take any of the actions referred to in paragraph (iii) of this Section 4(e), the Stockholders shall take such action promptly but in any event within three (3) Business Days following the date of such request.  Furthermore, the Corporation agrees that it shall use commercially reasonably efforts to obtain any waivers to the restrictive sale and purchase provisions of any “hold back” agreement that are reasonably requested by a Stockholder.

(f)            Copies of Registration Statements.  The Corporation will, if requested, prior to filing any Registration Statement pursuant to this Section 4 or any amendment or supplement thereto, furnish to the Stockholders, and thereafter furnish to the Stockholders, such number of copies of such Registration Statement, amendment and supplement thereto (in each case including all exhibits thereto and documents incorporated by reference therein) and the prospectus included in such Registration Statement (including each preliminary prospectus) as the Stockholders may reasonably request in order to facilitate the sale of the Registrable Securities by the Stockholders.

(g)           Expenses.  The Corporation shall pay all Registration Expenses in connection with a Corporation Registration or any Stockholder Registration, provided that each Stockholder shall pay all applicable underwriting fees, discounts and similar charges.

11

Section 5               Indemnification and Contribution.

(a)           The Corporation agrees to indemnify and hold harmless, to the fullest extent permitted by law, each Stockholder, its officers, directors, employees, controlling persons, fiduciaries, stockholders, and general or limited partners (and the officers, directors, employees and stockholders or general or limited partners thereof) and representatives from and against any and all losses, claims, damages, liabilities, costs and expenses (including attorneys’ fees) (“Losses”) caused by, arising out of, resulting from or related to (i) any untrue statement or alleged untrue statement of a material fact contained in any Registration Statement or prospectus relating to the Registrable Securities (as amended or supplemented if the Corporation shall have furnished any amendments or supplements thereto) or any preliminary prospectus, or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, provided, however, that such indemnity shall not apply to that portion of such Losses caused by, or arising out of, any untrue statement, or alleged untrue statement or any such omission or alleged omission, to the extent such statement or omission was made in reliance upon and in conformity with information furnished in writing to the Corporation by or on behalf of such Stockholder expressly for use therein, and (ii) any violation by the Corporation of any federal, state or common law rule, regulation or law applicable to the Corporation and relating to action required of or inaction by the Corporation in connection with any registration or offering of securities. Notwithstanding the preceding sentence, the Corporation shall not be liable in any such case to the extent that any such Loss arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission (x) made in any preliminary prospectus if (A) such selling Stockholder failed to deliver or cause to be delivered a copy of the prospectus to the Person asserting such Loss after the Corporation has furnished such selling Stockholder with a sufficient number of copies of the same and (B) the prospectus completely corrected in a timely manner such untrue statement or omission, or (y) in the prospectus, if such untrue statement or alleged untrue statement or omission or alleged omission is completely corrected in an amendment or supplement to the prospectus and the selling Stockholder thereafter fails to deliver such prospectus as so amended or supplemented prior to or concurrently with the sale of the securities to the Person asserting such Loss after the Corporation had furnished such selling Stockholder with a sufficient number of copies of the same. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of any Stockholder or representative of such Stockholder and shall survive the transfer of securities by such Stockholder.

(b)           Each Stockholder agrees to indemnify and hold harmless the Corporation, its officers and directors and each Person (if any) that controls the Corporation within the meaning of either Section 15 of the Securities Act or Section 20 of the Securities Exchange Act from and against any and all Losses caused by, arising out of, resulting from or related to any untrue statement or alleged untrue statement of a material fact contained in any Registration Statement or prospectus relating to Registrable Securities (as amended or supplemented if the Corporation shall have furnished any amendments or supplements thereto) or any preliminary prospectus, or any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the

12

statements therein not misleading, only to the extent such statement or omission (i) was made in reliance upon and in conformity with information furnished in writing by or on behalf of such Stockholder expressly for use in any Registration Statement or prospectus relating to the Registrable Securities, or any amendment or supplement thereto, or any preliminary prospectus and (ii) has not been corrected in a subsequent writing prior to or concurrently with the sale of the securities to the Person asserting such Loss. The selling Stockholders also will indemnify underwriters, selling brokers, dealer managers and similar securities industry professionals participating in the distribution, their officers and directors and each Person who controls such Persons (within the meaning of the Securities Act) to the same extent as provided above with respect to the indemnification of the Corporation, its officers and directors and each Person (if any) that controls the Corporation, if requested.  The Corporation and the selling Stockholders shall be entitled to receive indemnities from underwriters, selling brokers, dealer managers and similar securities industry professionals participating in the distribution, to the same extent as provided above with respect to information so furnished in writing by such Persons specifically for inclusion in any prospectus or Registration Statement.

(c)           In case any proceeding (including any governmental investigation) shall be instituted involving any Person in respect of which indemnity may be sought pursuant to Section 5(a) or Section 5(b), such Person (the “Indemnified Party”) shall promptly notify the Person against whom such indemnity may be sought (the “Indemnifying Party”) in writing (provided that the failure of the Indemnified Party to give notice as provided herein shall not relieve the Indemnifying Party of its obligations under this Section 5, except to the extent the Indemnifying Party is actually prejudiced by such failure to give notice), and the Indemnifying Party shall be entitled to participate in such proceeding and, unless in the reasonable opinion of outside counsel to the Indemnified Party a conflict of interest between the Indemnified Party and Indemnifying Party may exist in respect of such claim, to assume the defense thereof jointly with any other Indemnifying Party similarly notified, to the extent that it chooses, with counsel reasonably satisfactory to such Indemnified Party, and after notice from the Indemnifying Party to such Indemnified Party that it so chooses, the Indemnifying Party shall not be liable to such Indemnified Party for any legal or other expenses subsequently incurred by such Indemnified Party in connection with the defense thereof other than reasonable costs of investigation; provided, however, that (i) if the Indemnifying Party fails to take reasonable steps necessary to defend diligently the action or proceeding within twenty (20) days after receiving notice from such Indemnified Party that the Indemnified Party believes it has failed to do so, (ii) if such Indemnified Party who is a defendant in any action or proceeding which is also brought against the Indemnifying Party reasonably shall have concluded that there may be one or more legal defenses available to such Indemnified Party which are not available to the Indemnifying Party or (iii) if representation of both parties by the same counsel is otherwise inappropriate under applicable standards of professional conduct then, in any such case, the Indemnified Party shall have the right to assume or continue its own defense as set forth above (but with no more than one firm of counsel for all Indemnified Parties in each jurisdiction, except to the extent any Indemnified Party or Parties reasonably shall have concluded that there may be legal defenses available to such party or parties which are not available to the other Indemnified Parties or to the extent representation of all Indemnified Parties by the

13

same counsel is otherwise inappropriate under applicable standards of professional conduct) and the Indemnifying Party shall be liable for any expenses therefor. No Indemnifying Party shall, without the written consent of the Indemnified Party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the Indemnified Party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (A) includes an unconditional release of the Indemnified Party from all liability arising out of such action or claim and (B) does not include a statement as to, or an admission of, fault, culpability or a failure to act, by or on behalf of any Indemnified Party.

(d)           If the indemnification provided for in this Section 5 is unavailable to an Indemnified Party in respect of any losses, claims, damages or liabilities in respect of which indemnity is to be provided hereunder, then each Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall to the fullest extent permitted by law contribute to the amount paid or payable by such Indemnified Party as a result of such losses, claims, damages or liabilities in such proportion as is appropriate to reflect the relative fault of such party in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative fault of the Corporation (on the one hand) and a Stockholder (on the other hand) shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by such party and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

(e)           The Corporation and each Stockholder agree that it would not be just and equitable if contribution pursuant to this Section 5 were determined by pro rata allocation or by any other method of allocation that does not take account of the equitable considerations referred to in Section 5(d).  The amount paid or payable by an Indemnified Party as a result of the losses, claims, damages or liabilities referred to in Section 5(d) shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such Indemnified Party in connection with investigating or defending any such action or claim.  Notwithstanding the provisions of this Section 5, no Stockholder shall be liable for indemnification or contribution pursuant to this Section 5 for any amount in excess of the net proceeds of the offering received by such Stockholder, less the amount of any damages which such Stockholder has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission.  No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any Person who was not guilty of such fraudulent misrepresentation.

Section 6               Rule 144.

The Corporation covenants that so long as the Common Stock is registered pursuant to Section 12(b), Section 12(g) or Section 15(d) of the Securities Exchange Act, it will file any and all reports required to be filed by it under the Securities Act and the Securities Exchange Act (or,

14

if the Corporation is not required to file such reports, it will make publicly available such necessary information for so long as necessary to permit sales pursuant to Rule 144, Rule 144A or Regulation S under the Securities Act) and that it will take such further action as the Stockholders may reasonably request, all to the extent required from time to time to enable the Stockholders to sell Registrable Securities without registration under the Securities Act within the limitation of the exemptions provided by Rule 144, Rule 144A or Regulation S under the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the SEC. Upon the written request of any Stockholder, the Corporation will deliver to such Stockholder a written statement as to whether it has complied with such requirements.

Section 7               Board of Directors.

(a)           Nomination of Directors.  The Apollo Entities shall have the right to nominate for election to the Board:

(i)            no fewer than that number of directors that would constitute a majority of the number of directors that the Corporation would have if there were no vacancies on the Board, so long as the Apollo Entities collectively beneficially own at least 50% of the outstanding Stock of the Corporation; provided that nothing in this paragraph (i) of this Section 7(a) shall be construed to limit the right of the Apollo Entities to nominate directors to a number of such directors that is less than the number directors the Apollo Entities would be entitled to nominate pursuant to applicable law and the Corporation’s certificate of incorporation and bylaws;

(ii)           up to three (3) directors, so long as the Apollo Entities collectively beneficially own at least 30% of the outstanding Stock of the Corporation but less than 50% of the outstanding Stock of the Corporation;

(iii)          up to two (2) directors, so long as the Apollo Entities collectively beneficially own at least 20% of the outstanding Stock of the Corporation but less than 30% of the outstanding Stock of the Corporation; and

(iv)          up to one (1) directors, so long as the Apollo Entities collectively beneficially own at least 10% of the outstanding Stock of the Corporation but less than 20% of the outstanding Stock of the Corporation.

In the event the size of the Board is increased or decreased at any time to other than seven (7) directors, the Apollo Entities’ nomination rights under this Section 7(a) shall be proportionately increased or decreased, respectively, rounded up to the nearest whole number.

(b)           Election of Directors.  The Corporation shall take all action within its power to cause all nominees nominated pursuant to Section 7(a) to be included in the slate of nominees recommended by the Board to the Corporation’s stockholders for election as directors at each annual meeting of the stockholders of the Corporation (and/or in connection with any election by written consent) and the Corporation shall use

15

all reasonable best efforts to cause the election of each such nominee, including soliciting proxies in favor of the election of such nominees.

(c)           Replacement of Directors.  In the event that a vacancy is created at any time by the death, disability, retirement, resignation or removal (with or without cause) of a director nominated pursuant to Section 7(a) or designated pursuant to this Section 7(c), or in the event of the failure of any such nominee to be elected, the Apollo Entities shall have the right to designate a replacement to fill such vacancy.  The Corporation shall take all action within its power to cause such vacancy to be filled by the replacement so designated, and the Board shall promptly elect such designee to the Board.  Upon the written request of the Apollo Entities, the Corporation shall take all actions necessary to remove, with or without cause, any director previously nominated pursuant to Section 7(a) or designated pursuant to this Section 7(c), and to elect any replacement director designated by the Apollo Entities as provided in the first sentence of this Section 7(c).

(d)           Committees.  So long as the Apollo Entities collectively beneficially own at least 30% of the outstanding Stock of the Corporation, the Corporation shall take all action within its power to cause any committee of the Board to include in its membership at least one of the Apollo Entities’ nominees, except to the extent that such membership would violate applicable securities laws or stock exchange or stock market rules.

(e)           No Limitation.  The provisions of this Section 7 are intended to provide the Apollo Entities with the minimum Board representation rights set forth herein.  Nothing in this Agreement shall prevent the Corporation from having a greater number of nominees or designees of the Apollo Entities on the Board than otherwise provided herein.

(f)            Laws and Regulations.  Nothing in this Section 7 shall be deemed to require that any party hereto, or any Affiliate thereof, act or be in violation of any applicable provision of law, regulation, legal duty or requirement or stock exchange or stock market rule.

Section 8               Directors’ and Officers’ Insurance.

The Corporation shall maintain directors’ and officers’ liability insurance (including Side A coverage) covering the Corporation’s and its Subsidiaries’ directors and officers and issued by reputable insurers, with appropriate policy limits, terms and conditions (including “tail” insurance if necessary or appropriate).  The provisions of this Section 8 are intended to be for the benefit of, and will be enforceable by, each indemnified party, his or her heirs and his or her representatives and are in addition to, and not in substitution for, any other rights to indemnification or contribution that any such Person may have by contract or otherwise.

Section 9               Information.

For so long as the Apollo Entities collectively own 33 1/3% or greater of the outstanding Common Stock, Apollo will be entitled to the following contractual management rights with respect to the Corporation and its Subsidiaries:

16

(a)           Apollo shall be entitled to routinely consult with and advise senior management of the Corporation (defined as the Corporation’s Chief Executive Officer, Chief Financial Officer and Senior Vice President — Business Development and Land and above and, collectively, “Senior Management”) with respect to the Corporation’s business and financial matters, including management’s proposed annual operating plans, and, upon request, members of Senior Management will meet regularly (on a quarterly basis) during each year with representatives of Apollo (each such representative, a “Representative”) at the Corporation’s and/or its Subsidiaries’ facilities (or such other locations as the Corporation may designate) at mutually agreeable times for such consultation and advice, including to review progress in achieving said plans. The Corporation agrees to give due consideration to the advice given and any proposals made by Apollo;

(b)           Apollo may inspect all books and records and facilities and properties of the Corporation at reasonable times and intervals.  The Corporation shall furnish Apollo with such available financial and operating data and other information with respect to the business and properties of the Corporation and its Subsidiaries as Apollo may reasonably request and at Apollo’s expense.  The Corporation shall permit the Representatives to discuss the affairs, finances and accounts of the Corporation and its Subsidiaries with, and to make proposals and furnish advice to, Senior Management; and

(c)           The Corporation shall, after receiving notice from Apollo as to the identity of any Representative:  (i) permit such Representative to attend all meetings of the Board as an observer, (ii) provide such Representative advance notice of each such meeting, including such meeting’s time and place, at the same time and in the same manner as such notice is provided to the members of the Board, (iii) provide, with Apollo’s consent, the Representative with copies of all materials, including notices, minutes, consents and regularly compiled financial and operating data distributed to the members of the Board at the same time as such materials are distributed to such Board, and shall permit the Representative to have the same access to information concerning the business and operations of the Corporation, and (iv) permit the Representative to discuss the affairs, finances and accounts of the Corporation with, and to make proposals and furnish advice with respect thereto to, the Board, without voting, and the Board and the Corporation’s officers shall give due consideration thereto (recognizing that the ultimate discretion with respect to all such matters shall be retained by the Board).

The Corporation agrees to consider, in good faith, the recommendations of Apollo in connection with the matters on which it is consulted as described above, recognizing that the ultimate discretion with respect to all such matters shall be retained by the Corporation.

Section 10             Certain Actions.

(a)           Subject to the provisions of Section 10(b), without the approval of a majority the Board as provided for in the bylaws of the Corporation, which must include the approval of a majority of the directors nominated by Apollo Stockholders voting on such matter, the Corporation shall not, and (to the extent applicable) shall not permit any Subsidiary of the Corporation to:

17

(i)            amend, modify or repeal any provision of the certificate of incorporation and bylaws or similar organizational documents of the Corporation in a manner that adversely affects the Apollo Entities;

(ii)           issue additional equity interests of the Corporation, other than (A) any award under any stockholder approved equity compensation plan, (B) any intra-company issuance among the Corporation and its Subsidiaries or (C) any issuance of equity interests pursuant to the Exchange Agreement;

(iii)          merge or consolidate with or into any other entity, or transfer (by lease, assignment, sale or otherwise) all or substantially all of the Corporation’s and its Subsidiaries’ assets, taken as a whole, to another entity, or enter into or agree to undertake any transaction that would constitute a “Change of Control” as defined in the Corporation’s or its Subsidiaries’ principal credit facilities or note indentures;

(iv)          any (A) acquisition by the Corporation or any Subsidiary of the equity interests or assets of any Person, or the acquiring by the Corporation or any Subsidiary by any other manner of any business, properties, assets, or Persons, in one transaction or a series of related transactions or (B) disposition of assets of the Corporation or any Subsidiary or the shares or other equity interests of any Subsidiary, in each case where the amount of consideration for any such acquisition or disposition exceeds $100 million in any single transaction, or an aggregate amount of $200 million in any series of transactions during a calendar year;

(v)           the incurrence of indebtedness for borrowed money (including through capital leases, the issuance of debt securities or the guarantee of indebtedness of another Person) that would result in the Company’s total net indebtedness to adjusted EBITDA for the trailing twelve month period exceeding 2.50:1.0;

(vi)          terminate the Chief Executive Officer or designate a new Chief Executive Officer of the Corporation; or

(vii)         change the size of the Board.

(b)           The approval rights set forth in Section 10(a) shall terminate at such time as the Apollo Stockholders no longer collectively beneficially own at least 33 1/3% of the total number of shares of Common Stock outstanding at any time.

Section 11             Limitations.

Anything contained herein to the contrary notwithstanding, the Corporation’s obligations hereunder shall in all respects be subject to the terms and provisions of any lending or financing agreements to which the Corporation is a party with third persons who are not Affiliates of the Corporation or the Apollo Entities, provided that such terms and provisions apply ratably to all Stockholders.

18

Section 12             Legend on Stock Certificates.

Each certificate or book-entry notation representing shares of Stock owned by the Stockholders shall bear the following legend as and to the extent required under Section 2:

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES OR BLUE SKY LAWS.  THESE SECURITIES MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN EXEMPTION THEREFROM UNDER SAID ACT OR LAWS.  THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE ALSO SUBJECT TO A STOCKHOLDERS AGREEMENT DATED AS OF                    , 2013, AMONG THE ISSUER OF SUCH SECURITIES AND THE OTHER PARTIES NAMED THEREIN.  THE TERMS OF SUCH STOCKHOLDERS AGREEMENT INCLUDE, AMONG OTHER THINGS, RESTRICTIONS ON TRANSFER.  A COPY OF SUCH AGREEMENT MAY BE OBTAINED AT NO COST BY WRITTEN REQUEST MADE BY THE HOLDER OF RECORD OF THIS CERTIFICATE TO THE SECRETARY OF ATHLON ENERGY INC.

Section 13             Duration of Agreement.

This Agreement shall terminate automatically upon:  (i) the dissolution of the Corporation (unless the Corporation continues to exist after such dissolution as a limited liability company or in another form, whether incorporated in Delaware or another jurisdiction) or (ii) the consummation of a Control Disposition; provided, however, that (A) for so long as the Apollo Stockholders collectively own any Registrable Securities, Sections 3 and 4 may not be terminated without the prior written consent of Apollo, (B) for so long as the Apollo Stockholders collectively own at least 33 1/3% of the outstanding Common Stock, Sections 7, 9 and 10 may not be terminated without the prior written consent of Apollo and (C) the indemnification provisions of Section 5 and the covenants in Section 9 shall survive any termination. Any Stockholder who disposes of all of his, her or its Common Stock in conformity with the terms of this Agreement shall cease to be a party to this Agreement and shall have no further rights hereunder.

Section 14             Severability.

If any provision of this Agreement shall be determined to be illegal and unenforceable by any court of law, the remaining provisions shall be severable and enforceable in accordance with their terms.

Section 15             Governing Law; Jurisdiction.

(a)           This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York, without giving effect to its choice or conflict of law provisions or rules.

(b)           The parties to this Agreement agree that jurisdiction and venue in any action brought by any party hereto pursuant to this Agreement shall exclusively and properly lie in the federal courts of the United States of America located in the City and

19

County of New York, Borough of Manhattan, or the courts of the State of New York located in the City and County of New York, Borough of Manhattan.  By execution and delivery of this Agreement each party hereto irrevocably submits to the jurisdiction of such courts for himself and in respect of his property with respect to such action.  The parties hereto irrevocably agree that venue for such action would be proper in such court and hereby waive any objection that such court is an improper or inconvenient forum for the resolution of such action.  The parties further agree that the mailing by certified or registered mail, return receipt requested, of any process required by any such court shall constitute valid and lawful service of process against them, without necessity for service by any other means provided by statute or rule of court.

Section 16             JURY TRIAL.

BECAUSE DISPUTES ARISING IN CONNECTION WITH COMPLEX FINANCIAL TRANSACTIONS ARE MOST QUICKLY AND ECONOMICALLY RESOLVED BY AN EXPERIENCED AND EXPERT PERSON AND THE PARTIES WISH APPLICABLE STATE AND FEDERAL LAWS TO APPLY (RATHER THAN ARBITRATION RULES), THE PARTIES DESIRE THAT THEIR DISPUTES BE RESOLVED BY A JUDGE APPLYING SUCH APPLICABLE LAWS.  THEREFORE, TO ACHIEVE THE BEST COMBINATION OF THE BENEFITS OF THE JUDICIAL SYSTEM AND/OR ARBITRATION, THE PARTIES HERETO WAIVE ALL RIGHT TO TRIAL BY JURY IN ANY ACTION, SUIT OR PROCEEDING BROUGHT TO ENFORCE OR DEFEND ANY RIGHT OR REMEDIES UNDER THIS AGREEMENT OR ANY DOCUMENTS ENTERED INTO IN CONNECTION WITH THIS AGREEMENT AND THE TRANSACTIONS CONTEMPLATED HEREIN.

Section 17             Stock Dividends, Etc.

The provisions of this Agreement shall apply to any and all shares of capital stock of the Corporation or any successor or assignee of the Corporation (whether by merger, consolidation, sale of assets or otherwise) which may be issued in respect of, in exchange for or in substitution for the shares of Stock, by reason of any stock dividend, split, reverse split, combination, recapitalization, reclassification, merger, consolidation or otherwise in such a manner and with such appropriate adjustments as to reflect the intent and meaning of the provisions hereof and so that the rights, privileges, duties and obligations hereunder shall continue with respect to the capital stock of the Corporation as so changed.

Section 18             Benefits of Agreement.

This Agreement shall be binding upon and inure to the benefit of the Corporation and its successors and assigns and each Stockholder and any spouse of each individual Employee Stockholder and their permitted assigns, legal representatives, heirs and beneficiaries.  Notwithstanding anything to the contrary contained herein, but subject to Section 2(b), the Apollo Entities may assign their rights or obligations, in whole or in part, under this Agreement to one or more of their Affiliates and may assign their registration rights and obligations under Sections 3 and 4, in whole or in part, to any party to whom they transfer any shares of Stock.  Except as otherwise expressly provided herein, no Person not a party to this Agreement, as a

20

third-party beneficiary or otherwise, shall be entitled to enforce any rights or remedies under this Agreement.

Section 19             Notices.

All notices or other communications which are required or permitted hereunder shall be in writing and shall be deemed to have been given if (a) personally delivered or sent by telecopier, (b) sent by nationally recognized overnight courier or (c) sent by registered or certified mail, postage prepaid, return receipt requested, addressed as follows:

(i)            If to the Corporation, to:

Athlon Energy Inc.
420 Throckmorton Street, Suite 1200
Fort Worth, Texas 76102
Attention:  Robert C. Reeves
Telecopier:  (817) 984-8217

with copies to:

Latham & Watkins LLP
811 Main Street, Suite 3700
Houston, Texas 77002
Attn:  Sean T. Wheeler
Fax:  (713) 546-5401

(ii)           If to Apollo, to:

Apollo Management VII, L.P. 
9 West 57th Street
New York, New York 10019
Attn:  Rakesh Wilson and Laurie D. Medley
Fax:  (212) 515-3251

with copies to:

(iii)          If to the Stockholders, to their respective addresses set forth on Schedule A or to such other address as the party to whom notice is to be given may have furnished to such other party in writing in accordance herewith.  Any such communication shall be deemed to have been received (a) when delivered, if personally delivered or sent by telecopier, (b) the next Business Day after delivery, if sent by nationally recognized, overnight courier and (c) on the third (3rd) Business Day following the date on which the piece of mail containing such communication is posted, if sent by first-class mail.

21

Section 20             Modification; Waiver.

This Agreement may be amended, modified or supplemented only by a written instrument duly executed by (a) the Corporation and (b) (i) for so long as the Apollo Entities collectively own at least 33 1/3% of the Stock, the vote of the shares of Stock owned by the Apollo Entities, and (ii) only for matters that adversely affect the rights or obligations of the Employee Stockholders under this Agreement, a majority of the shares of Stock owned by the Employee Stockholders as of the date the vote is taken; provided that (A) for so long as the Apollo Stockholders own any Registrable Securities, Sections 3, 4 and 20 may not be amended without the prior written consent of Apollo, (B) Section 8 may not be amended without the prior written consent of Apollo and (iii) for so long as the Apollo Stockholders collectively own at least 33 1/3% of the outstanding Common Stock, Sections 7, 9 and 10 may not be amended without the prior written consent of Apollo. No course of dealing between the Corporation or its Subsidiaries and the Stockholders (or any of them) or any delay in exercising any rights hereunder will operate as a waiver of any rights of any party to this Agreement.  The failure of any party to enforce any of the provisions of this Agreement will in no way be construed as a waiver of such provisions and will not affect the right of such party thereafter to enforce each and every provision of this Agreement in accordance with its terms.

Section 21             Entire Agreement.

Except as otherwise expressly provided herein, this Agreement constitutes the entire agreement among the parties pertaining to the subject matter hereof and supersedes all prior and contemporaneous agreements and understandings of the parties in connection therewith, from and after the completion of the IPO.  Unless otherwise provided herein, any consent required by the Corporation may be withheld by the Corporation in its sole discretion.

Section 22             Inconsistent Arrangements and Dispositions.

No Stockholder shall enter into any stockholder agreements or arrangements of any kind with any Person with respect to any Stock on terms inconsistent with the provisions of this Agreement (whether or not such agreements or arrangements are with other Stockholders or with Persons that are not parties to this Agreement), including agreements or arrangements with respect to the acquisition or disposition of any Stock in a manner inconsistent with this Agreement.  Any Disposition or attempted Disposition in breach of this Agreement shall be void ab initio and of no effect.  In connection with any attempted Disposition in breach of this Agreement, the Corporation may hold and refuse to transfer any Stock or any certificate therefor, in addition to and without prejudice to any and all other rights or remedies which may be available to it or the Stockholders.  Each party to this Agreement acknowledges that a remedy at law for any breach or attempted breach of this Agreement will be inadequate, agrees that each other party to this Agreement shall be entitled to specific performance and injunctive and other equitable relief in case of any such breach or attempted breach, and further agrees to waive (to the extent legally permissible) any legal conditions required to be met for the obtaining of any such injunctive or other equitable relief (including posting any bond in order to obtain equitable relief).

22

Section 23             Counterparts.

This Agreement may be executed in any number of counterparts, and each such counterpart shall be deemed to be an original instrument, but all such counterparts taken together shall constitute but one agreement.  The failure of any Stockholder to execute this Agreement does not make it invalid as against any other Stockholder.

Section 24             Further Assurances.

Each party hereto shall do and perform or cause to be done and performed all such further acts and things and shall execute and deliver all such other agreements, certificates, instruments and other documents as any other party hereto reasonably may request in order to carry out the provisions of this Agreement and the consummation of the transactions contemplated hereby.

Section 25             Director and Officer Actions.

No director or officer of the Corporation shall be personally liable to the Corporation or any Stockholder as a result of any acts or omissions taken under this Agreement in good faith.

Section 26             Certain Certificates.

Each Stockholder that is an entity that was formed for the sole purpose of acquiring shares of Stock or that has no substantial assets other than shares of Stock or interests in shares of Stock agrees that (i) certificates of shares of its common stock or other instruments reflecting equity interests in such entity (and the certificates for shares of common stock or other equity interests in any similar entities controlling such entity) will note the restrictions contained in this Agreement on the transfer of Stock as if such common stock or other equity interests were shares of Stock and (ii) no such shares of common stock or other equity interests may be transferred to any Person other than in accordance with the terms and provisions of this Agreement as if such shares or equity interests were shares of Stock.

Section 27             Apollo Stockholder Parties.

In the event that any Apollo Entity that is not an Apollo Stockholder as of the time this Agreement becomes effective thereafter becomes an Apollo Stockholder, such Apollo Entity shall automatically become party to this Agreement and this Agreement shall be amended and restated to provide that the Apollo Entities or a designee of the Apollo Entities shall have all of the rights and obligations of the Apollo Entities hereunder.

[Signature Page to Follow]

23

The parties have signed this agreement as of the date first written above.

ATHLON ENERGY INC.
By:
	Robert C. Reeves
	Chief Executive Officer
STOCKHOLDERS:
APOLLO ATHLON HOLDINGS, L.P.
By:	Apollo Advisors VII (APO DC), L.P.,
	its general partner
By:	Apollo Advisors VII (APO DC-GP), LLC,
	its general partner
By:
	Name:	Laurie D. Medley
	Title:	Vice President
AP OVERSEAS VII (ATHLON FC) HOLDINGS, L.P.
By:	Apollo Advisors VII (APO DC), L.P.,
	its general partner
By:	Apollo Advisors VII (APO DC), LLC,
	its general partner
By:
	Name:	Laurie D. Medley
	Title:	Vice President

The parties have signed this agreement as of the date first written above.

Robert C. Reeves

Nelson K. Treadway

Bud W. Holmes

Jennifer L. Palko

EX-10.10

Exhibit 10.10

ADVISORY SERVICES AND TRANSACTION FEE TERMINATION AGREEMENT

This Advisory Services and Transaction Fee Termination Agreement (this “Agreement”) is made as of this      day of            , 2013, by and among Athlon Holdings LP, a Delaware Limited Partnership (the “Partnership”) (as assignee of Athlon Energy LP, a Delaware limited partnership), Apollo Management VII, L.P., a Delaware limited partnership (“Management VII”) and Apollo Global Securities, LLC, a Delaware limited liability company (“AGS”).

WHEREAS, the Partnership and Management VII previously entered into that certain Services Agreement, dated as of August 23, 2010 (the “Services Agreement”), pursuant to which Management VII agreed to make its expertise available to the Partnership and its subsidiaries from time to time in rendering certain consulting and investment advisory services related to the business and affairs of the Partnership and its subsidiaries and affiliates and the review and analysis of certain financial and other transactions (the “Advisory Services”);

WHEREAS, in consideration of the provision by Management VII of the Advisory Services, and pursuant to Section 4 of the Services Agreement, the Partnership agreed to pay to Management VII, within 30 days of the end of each calendar quarter, a fee equal to the higher of (i) 1.00% of earnings before interest, income taxes, depletion, depreciation, and amortization, and exploration expense for the preceding quarter and (ii) $62,500 (the “Consulting Fee”) beginning on the date of the Services Agreement and terminating on the tenth anniversary thereof;

WHEREAS, the Partnership and AGS (as assignee of Management VII) previously entered into that certain Transaction Fee Agreement, dated as of August 23, 2010 (the “Fee Agreement”), pursuant to which AGS agreed to make its expertise available to the Partnership and its subsidiaries from time to time in rendering certain consulting and investment advisory services related to the Partnership’s (i) investment in an entity, (ii) merger, or (iii) acquisition of equity and/or assets of an entity (the “Transactions”) in exchange for a fee equal to 2.00% of the total equity invested by the Partnership pursuant to said Transactions (the “Transaction Fee”);

WHEREAS, Athlon Energy Inc., a Delaware corporation and holder of a majority of the limited partner interests of the Partnership, plans to commence an initial public offering of its common stock (the “IPO”) and has filed a registration statement on Form S-1;

WHEREAS, pursuant to Section 2 of the Services Agreement, the Services Agreement may be terminated at such time as is mutually agreed upon by the Partnership and Management VII; and

WHEREAS, pursuant to Section 4 of the Fee Agreement, the Fee Agreement may be terminated at such time as is mutually agreed upon by the Partnership and AGS.

NOW, THEREFORE, in consideration of the premises and the mutual covenants and agreements contained herein, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties agree as follows:

Section 1.Termination of Advisory Services and Services Agreement. Effective immediately upon consummation of the IPO (the “Closing”) and without any further action by

1

the Partnership or Management VII, each of the Partnership and Management VII shall be released from any and all obligations and liabilities (other than pursuant to Section 5 of the Services Agreement relating to indemnification) with respect to provision of the Advisory Services and payment of the Consulting Fee or any other fees pursuant to the Services Agreement (other than (i) the Termination Fee (as defined below) and (ii) the Deferred Amount (as defined below)), and the Services Agreement (other than Section 5 thereof) shall have no further force or effect.

Section 2.Payment of Termination Fee. In consideration of the termination provided in Section 1 above, the Partnership shall pay to Management VII, via wire transfer of immediately available funds payable immediately upon the Closing, a lump-sum amount equal to the sum of (i) $2.5 million (the “Termination Fee”) and (ii) the Deferred Amount. For the avoidance of doubt, each of the Partnership and Management VII agrees that the payment of the Termination Fee shall be deemed to be in full satisfaction of any and all obligations by the Partnership to terminate the Services Agreement. “Deferred Amount” means, as of the Closing, any unreimbursed expenses of Management VII owing and payable pursuant to Section 4(d) of the Services Agreement.

Section 3.Termination of Transaction Fee Agreement. Effective immediately upon the Closing and without any further action by the Partnership or AGS, each of the Partnership and AGS shall be released from any and all obligations and liabilities with respect to the provision of services rendered pursuant to a Transaction and payment of a Transaction Fee, and the Fee Agreement shall have no further force or effect.

Section 4.Miscellaneous.

(a)Effect of Agreement. Upon the payment of the Termination Fee and the Deferred Amount, the Services Agreement shall be terminated and of no further force and effect and no party shall have any further rights or obligations under the Services Agreement (other than Section 5 thereof). Upon Closing, the Fee Agreement shall be terminated and of no further force and effect and no party shall have any further rights or obligations under the Fee Agreement.

(b)Entire Agreement; Amendments. This Agreement contains the entire understanding of the parties with respect to its subject matter and supersedes any and all prior agreements, and neither it nor any part of it may in any way be altered, amended, extended, waived, discharged or terminated except by a written agreement signed by each of the parties hereto.

(c)Assignment. This Agreement shall be binding upon and shall inure to the benefit of the successors and assigns of each of the Partnership, Management VII, and AGS.

(d)Governing Law. This Agreement shall be governed by and construed and enforced in accordance with the laws of the State of New York (without giving effect to principles of conflicts of laws).

2

(e)Headings. Section headings are used for convenience only and shall in no way affect the construction of this Agreement.

(f)Counterparts. This Agreement may be executed in counterparts, and each such counterpart shall be deemed to be an original instrument, but all such counterparts together shall constitute but one agreement.

[remainder of this page intentionally left blank]

3

IN WITNESS WHEREOF, the undersigned have duly executed this Advisory Services and Transaction Fee Termination Agreement as of the date first above written.

ATHLON HOLDINGS LP
By:
	Name:
	Title:
APOLLO MANAGEMENT VII, L.P.
By:	Apollo Management VII, LP
	its manager
By:	Apollo Management VII, LLC
	its general partner
By:
	Name:
	Title:
APOLLO GLOBAL SECURITIES, LLC
By:
	Name:
	Title:

[Signature page to Advisory Services and Transaction Fee Termination Agreement]

EX-10.11

Exhibit 10.11

AMENDED AND RESTATED
LIMITED PARTNERSHIP AGREEMENT

OF

ATHLON HOLDINGS LP

A Delaware Limited Partnership

Dated as of              , 2013

AMENDED AND RESTATED
LIMITED PARTNERSHIP AGREEMENT
OF
ATHLON HOLDINGS LP

TABLE OF CONTENTS

ARTICLE I DEFINITIONS	1
Section 1.1. Definitions	1
Section 1.2. Other Definitions	7
Section 1.3. Directly or Indirectly	7
Section 1.4. Construction	7
ARTICLE II ORGANIZATION	7
Section 2.1. Prior Organization and Recapitalization	7
Section 2.2. Name	8
Section 2.3. Registered Office; Registered Agent; Principal Office in the United States; Other Offices	8
Section 2.4. Purpose	8
Section 2.5. Foreign Qualification	8
Section 2.6. Term	8
ARTICLE III PARTNERS; PARTNERSHIP UNITS	9
Section 3.1. Partners	9
Section 3.2. Partnership Interests; Issuances of Additional Units	9
Section 3.3. Register	9
Section 3.4. Transfer of a Limited Partner Interest	10
Section 3.5. Substituted Limited Partners	11
Section 3.6. No Publicly Traded Partnership	12
Section 3.7. Splits, Distributions and Reclassifications	12
Section 3.8. Cancellation of Common Stock and Units	12
Section 3.9. Incentive Plans	12
Section 3.10. Offerings of Common Stock	13
ARTICLE IV CAPITAL COMMITMENTS	13
Section 4.1. Capital Accounts	13
Section 4.2. Return of Contributions	15
Section 4.3. Advances by Partners	15
ARTICLE V ALLOCATIONS AND DISTRIBUTIONS	15
Section 5.1. Allocations for Capital Account Purposes	15
Section 5.2. Allocations for Tax Purposes	18
Section 5.3. Distributions	20

i

ARTICLE VI MANAGEMENT AND OPERATIONS OF THE PARTNERSHIP	20
Section 6.1. Management Generally	20
Section 6.2. Reserved	20
Section 6.3. The Board of Supervisors	20
Section 6.4. Officers	21
Section 6.5. Reserved	22
Section 6.6. Resolution of Conflicts of Interest by the Board of Supervisors	22
Section 6.7. Other Matters Concerning the Board of Supervisors	23
Section 6.8. Reliance by Third Parties	23
Section 6.9. Reserved	24
Section 6.10. Reserved	24
Section 6.11. Reserved	24
Section 6.12. Grant of Authority	24
Section 6.13. Costs and Expenses and Compensation	24
ARTICLE VII RIGHTS OF PARTNERS	25
Section 7.1. Access to Information	25
Section 7.2. Reserved	25
Section 7.3. Confidentiality	25
Section 7.4. Liability to Third Parties	26
ARTICLE VIII TAXES	26
Section 8.1. Tax Returns	26
Section 8.2. Tax Elections	26
Section 8.3. Tax Matters Partner	27
Section 8.4. Tax Matters	27
Section 8.5. Withholding Taxes	27
ARTICLE IX BOOKS, RECORDS, REPORTS, AND BANK ACCOUNTS	28
Section 9.1. Maintenance of Books	28
Section 9.2. Bank Accounts	28
ARTICLE X WITHDRAWAL OF GENERAL PARTNER	28
Section 10.1. Withdrawal of General Partner	28
ARTICLE XI DISSOLUTION, MERGER, LIQUIDATION AND TERMINATION	28
Section 11.1. Dissolution	28
Section 11.2. Merger or Sale of All of the Assets	29
Section 11.3. Liquidation and Termination	29
Section 11.4. Cancellation of Filing	30
ARTICLE XII GENERAL PROVISIONS	30

ii

Section 12.1. Offset	30
Section 12.2. Notices	30
Section 12.3. Entire Agreement; Supersedure	30
Section 12.4. Effect of Waiver or Consent	31
Section 12.5. Amendment or Modification	31
Section 12.6. Binding Effect	31
Section 12.7. Governing Law; Jurisdiction; Waiver of Jury Trial	32
Section 12.8. Severability	33
Section 12.9. Further Assurances	33
Section 12.10. Counterparts	33

Schedule A — Schedule of Limited Partners and Capital Contributions

Exhibit A — Adoption Agreement

Exhibit B — Adoption Agreement for Family Members

Exhibit C — Consent of Spouse

iii

AMENDED AND RESTATED

LIMITED PARTNERSHIP AGREEMENT

OF

ATHLON HOLDINGS LP

This AMENDED AND RESTATED LIMITED PARTNERSHIP AGREEMENT (this “Agreement”) of ATHLON HOLDINGS LP (the “Partnership”) is entered into by and among Athlon Holdings GP LLC, as the sole general partner (the “General Partner”), and the Limited Partners (as defined below) set forth on Schedule A hereto, as of                    , 2013 (the “Effective Date”).

WHEREAS, the General Partner has formed a limited partnership under the Act (as defined below) by filing the Certificate of Limited Partnership with the Secretary of State of the State of Delaware on July 22, 2011.

WHEREAS, on April 26, 2013, certain Limited Partners exchanged their Class A limited partner interests and Class B limited partner interests in the Partnership for shares of common stock, par value $0.01 per share (“Common Stock”) of Athlon Energy Inc., a Delaware corporation (“Athlon Energy”), whereupon (a) Athlon Energy became a Limited Partner and (b) the Limited Partners (other than Athlon Energy) continued to hold Class A limited partner interests.

WHEREAS, Athlon Energy intends to make an initial public offering (the “IPO”) of shares of its Common Stock.

WHEREAS, the General Partner and the Limited Partners desire to amend and restate the limited partnership agreement of the Partnership, dated as of July 22, 2011, pursuant to which the Limited Partners’ limited partner interests will convert into Units (as defined below) and such Limited Partners (other than Athlon Energy) shall have the right to exchange their Units for shares of Common Stock of Athlon Energy.

WHEREAS, in consideration of the mutual covenants, rights and obligations set forth in this Agreement, the benefits to be derived therefrom, and other good and valuable consideration, the receipt and the sufficiency of which each Partner acknowledges and confesses, the Partners agree as follows:

ARTICLE I

DEFINITIONS

Section 1.1. Definitions.  As used in this Agreement, the following terms have the following meanings:

“Act” means the Delaware Revised Uniform Limited Partnership Act, 6 Del. Code §17-101 et seq., and any successor statute, as amended from time to time.

“Adjusted Capital Account” means the Capital Account maintained for each Partner, (i) increased by any amounts that such Partner is obligated to restore or is treated as obligated to

restore under Treasury Regulation Sections 1.704-1(b)(2)(ii)(c) and (d), 1.704-2(g)(1) and 1.704-2(i)(5), including the amount of Partnership liabilities (other than Partner Nonrecourse Liabilities) allocable to such Partner under Section 752 of the Code with respect to which such Partner bears the Economic Risk of Loss and (ii) reduced by amounts described in Treasury Regulations Sections 1.704-1(b)(2)(ii)(d)(4), (5) and (6).

“Adoption Agreement” means an agreement of a newly admitted Limited Partner substantially in the form of Exhibit A.

“Adoption Agreement for Family Members” means an agreement of a Family Member of a Partner substantially in the form of Exhibit B.

“Affiliate” means, with respect to any Person, any other Person Controlling, Controlled by, or under common Control with such first Person.

“Agreed Allocation” means any allocation, other than a Required Allocation, of an item of income, gain, loss or deduction pursuant to the provisions of Section 5.1, including, without limitation, a Curative Allocation (if appropriate to the context in which the term “Agreed Allocation” is used).

“Agreement” means this Amended and Restated Limited Partnership Agreement, as the same may be amended, modified or supplemented from time to time.

“Assign” means to sell, transfer, assign, exchange pledge, hypothecate, mortgage or otherwise dispose of a Partnership Interest, whether voluntarily or by operation of law.  “Assignor,” “Assignee,” “Assigning” and “Assignment” have meanings corresponding to the foregoing.

“Athlon Energy” is defined in the recitals to this Agreement.

“Board of Supervisors” shall mean the board of supervisors of the Partnership composed of not less than two (2) members appointed by the General Partner and to whom the General Partner irrevocably delegates, and in which is vested, pursuant to Section 6.1, the power to manage the business and activities of the Partnership (other than the General Partner’s duties as “tax matters partner” under Section 8.3 hereof).  The Board of Supervisors shall constitute a committee within the meaning of Section 17-303(b)(7) of the Act.

“Book Value” means, with respect to any property, such property’s adjusted basis for federal income tax purposes, except (i) the Book Value of any property contributed by a Partner to the Partnership shall be the fair market value of such property as determined by the Board of Supervisors reduced (but not below zero) by all depreciation, amortization and cost recovery charged to the Capital Accounts in respect of such property, and (ii) the Book Values of any property adjusted pursuant to Sections 4.1(c)(i) or (ii) shall be so adjusted and thereafter shall be reduced (but not below zero) by all depreciation, amortization and cost recovery charged to the Partners’ Capital Accounts in respect of such property.  The Book Value of each oil and gas property of the Partnership shall be reduced by the Simulated Depletion attributable to such property.

2

“Capital Account” means the capital account maintained for a Partner pursuant to Section 4.1.

“Capital Contribution” means any contribution by a Limited Partner to the capital of the Partnership.

“Certificate” is defined in Section 2.1.

“Code” means the Internal Revenue Code of 1986 and any successor statute, as amended from time to time.

“Common Stock” is defined in the recitals to this Agreement.

“Control” (or variations thereof) means the possession, directly or indirectly, through one or more intermediaries, of the following:  (i) in the case of a corporation, more than 50% of the voting power of the outstanding voting securities thereof; (ii) in the case of a limited liability company, partnership, limited partnership or venture, the right to more than 50% of the distributions therefrom (including liquidating distributions); (iii) in the case of a trust or estate, more than 50% of the beneficial interest therein; (iv) in the case of any other Entity, more than 50% of the economic or beneficial interest therein; or (v) in the case of any Entity, the power or authority, through ownership of voting securities, by contract or otherwise, to direct the management, activities or policies of the Entity.

“Covered Matters” is defined in Section 12.7(b).

“Curative Allocation” means any allocation of an item of income, gain, deduction, loss or credit pursuant to the provisions of Section 5.1(b)(ix).

“Depreciation” means, for each taxable year, an amount equal to the depreciation, amortization or other cost recovery deduction allowable for Federal income tax purposes with respect to property for such taxable year, except that (i) with respect to any property the Book Value of which differs from its adjusted tax basis for Federal income tax purposes and which difference is being eliminated by use of the “remedial method” pursuant to Treasury Regulation Section 1.704-3(d), Depreciation for such taxable year shall be the amount of book basis recovered for such taxable year under the rules prescribed by Treasury Regulation Section 1.704-3(d)(2), and (ii) with respect to any other property the Book Value of which differs from its adjusted tax basis at the beginning of such taxable year, Depreciation shall be an amount which bears the same ratio to such beginning Book Value as the Federal income tax depreciation, amortization, or other cost recovery deduction for such taxable year bears to such beginning adjusted tax basis; provided that if the adjusted tax basis of any property at the beginning of such taxable year is zero, Depreciation with respect to such property shall be determined with reference to such beginning value using any reasonable method selected by the Board of Supervisors.

“Dispose,” “Disposing” or “Disposition” means a sale, assignment, transfer, exchange, pledge, grant of a security interest, or other disposition or encumbrance, or the acts thereof.

3

“Economic Risk of Loss” has the meaning set forth in Treasury Regulation Section 1.752-2(a).

“Effective Date” is defined in the introductory paragraph of this Agreement.

“Entity” means any corporation, limited liability company, general partnership, limited partnership, venture, trust, business trust, estate or other entity.

“Exchange Act” means the Securities Exchange Act of 1934, as amended.

“Exchange Agreement” means the Exchange Agreement, dated as of the Effective Date, by and among Athlon Energy and the Limited Partners.

“Exchange Transaction” means the exchange of Units for shares of Common Stock, pursuant to, and in accordance with, the Exchange Agreement.

“Family Member” means, for any Partner who is an individual, a spouse, lineal ancestor, lineal descendant, legally adopted child, brother or sister of such Partner, or lineal descendant or legally adopted child of a brother or sister of such Partner.

“General Partner” means Athlon Holdings GP LLC, a Delaware limited liability company, and its successors and permitted assigns as general partner of the Partnership.  The General Partner has no obligation to make Capital Contributions or right to receive distributions under this Agreement.

“Incentive Plan” means the Athlon Energy Inc. 2013 Incentive Award Plan and any other equity incentive plan of Athlon Energy.

“IPO” is defined in the recitals to this Agreement.

“Legal Action” is defined in Section 12.7(b).

“Limited Partner” means any Person (i) executing this Agreement or any other writing evidencing the interest of such Person to become a limited partner of the Partnership, (ii) complying with the conditions for becoming a limited partner of the Partnership as set forth in this Agreement or any other writing and requesting (orally, in writing or by other action such as payment for a Partnership Interest) that the records of the Partnership reflect such admission, and (iii) hereafter admitted to the Partnership as a limited partner as herein provided; but shall not include any Person who has ceased to be a limited partner of the Partnership.

“Net Income” or “Net Loss” means, for each taxable year, an amount equal to the Partnership’s taxable income or loss, respectively, for such taxable year, determined in accordance with Code Section 703(a) (for this purpose, all items of income, gain, loss, or deduction required to be stated separately pursuant to Code Section 703(a)(1) shall be included in taxable income or loss), with the following adjustments (without duplication):

4

(i)            Any income of the Partnership that is exempt from federal income tax and not otherwise taken into account in computing Net Income or Net Loss pursuant to this definition of “Net Income” or “Net Loss” shall be added to such taxable income or loss;

(ii)           Any expenditures of the Partnership described in Code Section 705(a)(2)(B) or treated as Code Section 705(a)(2)(B) expenditures pursuant to  Treasury Regulation Section 1.704-1(b)(2)(iv)(i), and not otherwise taken into account in computing Net Income or Net Loss pursuant to this definition of “Net Income” and “Net Loss” shall be subtracted from such taxable income or loss;

(iii)          In the event the Book Value of any partnership property is adjusted pursuant to Section 4.1(c), the amount of any Unrealized Gain or Unrealized Loss attributable to such property shall be taken into account for purposes of computing Net Income or Net Loss;

(iv)          Gain or loss resulting from any disposition of property with respect to which gain or loss is recognized for Federal income tax purposes shall be computed by reference to the Book Value of the property disposed of, notwithstanding that the adjusted tax basis of such property differs from its Book Value;

(v)           In lieu of the depreciation, amortization, and other cost recovery deductions taken into account in computing such taxable income or loss, there shall be taken into account Depreciation and Simulated Depletion for such taxable year.

(vi)          To the extent an adjustment to the adjusted tax basis of any asset pursuant to Code Section 734(b) is required, pursuant to Treasury Regulation Section 1.704-1(b)(2)(iv)(m)(4), to be taken into account in determining Capital Account balances as a result of a distribution other than in liquidation of a Partner’s interest in the Partnership, the amount of such adjustment shall be treated as an item of gain (if the adjustment increases the basis of the asset) or an item of loss (if the adjustment decreases such basis) from the disposition of such asset and shall be taken into account for purposes of computing Net Income or Net Loss; and

(vii)         Any items that are allocated pursuant to Sections 5.1(b), 5.1(c) or 5.1(d) shall not be taken into account in computing Net Income and Net Loss.

“Officer” means any Person designated as an officer of the Partnership pursuant to Section 6.4.

“Partner” means any General Partner or Limited Partner.

“Partner Minimum Gain” has the meaning assigned to that term in Treasury Regulation Section 1.704-2(i).

“Partner Nonrecourse Debt” has the meaning assigned to that term in Treasury Regulation Section 1.704-2(b)(4).

“Partner Nonrecourse Deductions” has the meaning assigned to that term in Treasury Regulation Section 1.704-2(i)(1).

5

“Partnership” is defined in the recitals to this Agreement.

“Partnership Interest” means all of the interest of a Partner in the Partnership, including, without limitation, rights to distributions (liquidating or otherwise), if any, allocations, information, and, if applicable, to consent or approve.

“Partnership Minimum Gain” has the meaning assigned to that term in Treasury Regulation Section 1.704-2(d).

“Partnership Nonrecourse Deductions” has the meaning assigned to that term in Treasury Regulation Section 1.704-2(c).

“Partnership Nonrecourse Liabilities” has the meaning assigned to the term “nonrecourse liability” in Treasury Regulation Section 1.752-1(a)(2).

“Person” means any natural person or Entity.

“Percentage Interest” means, with respect to any Partner, the quotient obtained by dividing the number of Units then owned by such Partner by the number of Units then owned by all Partners.

“Recapture Income” means the amount of gain realized upon the sale or other taxable disposition of a Partnership asset, if any, that is required to be treated as ordinary income under Sections 1245 or 1250 of the Code.

“Required Allocations” means any allocation (or limitation imposed on any allocation) of an item of income, gain, deduction or loss pursuant to Sections 5.1(b)(i), 5.1(b)(ii), 5.1(b)(iii), 5.1(b)(iv), 5.1(b)(v), 5.1(b)(vi) and 5.1(b)(viii), such allocations (or limitations thereon) being directly or indirectly required by the Treasury Regulations promulgated under Section 704(b) of the Code.

“Securities Act” means the Securities Act of 1933, as amended.

“Simulated Basis” shall mean the Book Value of any oil and gas property.

“Simulated Depletion” shall mean, with respect to each oil and gas property, a depletion allowance computed in accordance with federal income tax principles (as if the Book Value of the property were its adjusted tax basis) and in the manner specified in Treasury Regulation Section 1.704-1(b)(2)(iv)(k)(2).  For purposes of computing Simulated Depletion with respect to any property, the basis of such property shall be deemed to be the Book Value of such property, and in no event shall such allowance, in the aggregate, exceed such Book Value.

“Substituted Limited Partner” means a Person who is admitted as a Limited Partner to the Partnership pursuant to Section 3.5(b) in place of and with all the rights of a Limited Partner and who is shown as a Limited Partner on the books and records of the Partnership.

“Tax Receivable Agreement” means the Tax Receivable Agreement, dated as of the Effective Date, by and among Athlon Energy, the Partnership and the Limited Partners.

6

“Treasury Regulations” or “Treas. Reg.” means U.S. Federal income tax regulations under the Code as such Treasury Regulations are amended from time to time.  All references herein to specific sections of the Treasury Regulations shall be deemed also to refer to any corresponding provisions of succeeding Treasury Regulations.

“Units” means units and any other interests in the Partnership denominated as “Units” that is established in accordance with this Agreement, which shall constitute limited partner interests in the Partnership as provided in this Agreement and under the Act, entitling the holders thereof to the relative rights, title and interests in the profits, losses, deductions and credits of the Partnership at any particular time as set forth in this Agreement, and any and all other benefits to which a holder thereof may be entitled as a Partner as provided in this Agreement, together with the obligations of such Partner to comply with all terms and provisions of this Agreement.

“Unrealized Gain” attributable to any item of Partnership property means, as of any date of determination, the excess, if any, of (i) the fair market value of such property as of such date (as determined by the Board of Supervisors in its good faith discretion using any reasonable method it may adopt) over (ii) the Book Value of such property as of such date (prior to any adjustment to be made pursuant to Section 4.1(c) as of such date).

“Unrealized Loss” attributable to any item of Partnership property means, as of any date of determination, the excess, if any, of (i) the Book Value of such property as of such date (prior to any adjustment to be made pursuant to Section 4.1(c) as of such date) over (ii) the fair market value of such property as of such date (as determined by the Board of Supervisors in its good faith discretion using any reasonable method it may adopt).

Section 1.2. Other Definitions.  Other terms defined herein have the meanings so given them.

Section 1.3. Directly or Indirectly.  Where any provision in this Agreement refers to action to be taken by any Person, or which such Person is prohibited from taking, such provision shall be applicable whether such action is taken directly or indirectly by such Person, including actions taken by or on behalf of any Affiliate of such Person.

Section 1.4. Construction.  Whenever the context requires, the gender of all words used in this Agreement includes the masculine, feminine, and neuter.  All references to Articles and Sections refer to articles and sections of this Agreement, all references to “including” shall be construed as meaning “including without limitation” and all references to Exhibits are to Exhibits attached to this Agreement, each of which is made a part for all purposes.

ARTICLE II

ORGANIZATION

Section 2.1. Prior Organization and Recapitalization. The Partnership was organized as a Delaware limited partnership by the filing of a certificate of limited partnership in the office of the Secretary of State of the State of Delaware (the “Certificate”) on July 22, 2011.  On the date hereof, the Partnership Interest of each Partner will be exchanged for, and formally denominated as, the number of “Units” as set forth on Schedule A hereto.  On the closing of the IPO, Athlon

7

Energy will contribute the net proceeds from the primary offering of newly issued shares of Common Stock in the IPO in exchange for a number of Units equal to the number of shares of Common Stock issued in such offering in accordance with Section 3.10, and the Board of Supervisors shall amend Schedule A to reflect the Units of each Partner after giving effect to the IPO.

Section 2.2. Name.  From July 22, 2011, the name of the Partnership is “Athlon Holdings LP,” and all Partnership business must be conducted in such name or such other names that comply with applicable law as the Board of Supervisors may select from time to time.

Section 2.3. Registered Office; Registered Agent; Principal Office in the United States; Other Offices.  The registered office of the Partnership in the State of Delaware shall be the initial registered office designated in the Certificate or such other office (which need not be a place of business of the Partnership) as the Board of Supervisors may designate from time to time in the manner provided by law.  The registered agent of the Partnership in the State of Delaware shall be the initial registered agent designated in the Certificate or such other Person or Persons as the Board of Supervisors may designate from time to time in the manner provided by law.  The registered office of the Partnership in the United States shall be at the place specified in the Certificate of Limited Partnership of the Partnership, or such other place(s) as the Board of Supervisors may designate from time to time.  The Partnership may have such other offices as the Board of Supervisors may determine appropriate.

Section 2.4. Purpose.  The purpose of the Partnership will be to engage directly and indirectly in the acquisition, exploration, exploitation and development of oil and natural gas assets, the acquisition of leases and other real property in connection therewith, and to engage in such other activities as are permitted hereby or are incidental or ancillary thereto as the Board of Supervisors deems necessary or advisable, all upon the terms and conditions set forth in this Agreement.

Section 2.5. Foreign Qualification.  Prior to conducting business in any jurisdiction other than the State of Delaware, the  Board of Supervisors shall cause the Partnership to comply, to the extent procedures are available, with all requirements necessary to qualify the Partnership as a foreign limited partnership in such jurisdiction.  Each Partner shall execute, acknowledge, swear to and deliver all certificates and other instruments conforming to this Agreement that are necessary or appropriate to qualify, or, as appropriate, to continue or terminate such qualification of, the Partnership as a foreign limited partnership in all such jurisdictions in which the Partnership may conduct business.

Section 2.6. Term.  The term of the Partnership commenced upon the filing of the Certificate in accordance with the Act and shall continue until the dissolution of the Partnership in accordance with the provisions of Article XI. The existence of the Partnership as a separate legal entity shall continue until the cancellation of the Certificate as provided in the Act.

8

ARTICLE III

PARTNERS; PARTNERSHIP UNITS

Section 3.1. Partners.  The Limited Partners and the General Partner are the sole Partners of the Partnership as of the date hereof.

Section 3.2. Partnership Interests; Issuances of Additional Units.  Interests in the Partnership shall be represented by Units or such other Partnership securities as the Board of Supervisors may establish in its sole discretion in accordance with the terms hereof.  In addition to the Units, the Board of Supervisors may create other equity interests in the Partnership or other Partnership securities from time to time in accordance with such procedures and subject to such conditions and restrictions and with such rights, obligations, powers, designations, preferences and other terms, which may be senior to the Units, any then existing or future equity interests in the Partnership or other Partnership securities, as the Board of Supervisors shall determine from time to time in its sole discretion, without the vote or consent of any Limited Partner or any other Person, including (i) the right of such Units, other equity interests or other Partnership securities to share in Net Income and Net Loss or items thereof; (ii) the right of such Units, other equity interests or other Partnership securities to share in Partnership distributions; (iii) the rights of such Units, other equity interests or other Partnership securities upon dissolution and liquidation of the Partnership; (iv) whether, and the terms and conditions upon which, the Partnership may or shall be required to redeem such Units or other equity interests or other Partnership securities (including sinking fund provisions); (v) whether such Units, other equity interests or other Partnership securities are issued with the privilege of conversion or exchange and, if so, the terms and conditions of such conversion or exchange; (vi) the terms and conditions upon which such Units, other equity interests or other Partnership securities will be issued, evidenced by certificates and assigned or transferred; (vii) the method for determining the total Percentage Interest as to such Units or other equity interests or other Partnership securities; (viii) the terms and conditions of the issuance of such Units, other equity interests or other Partnership securities; and (ix) the right, if any, of the holder of such Units, other equity interests or other Partnership securities to vote on Partnership matters, including matters relating to the relative designations, preferences, rights, powers and duties of such Units, other equity interests or other Partnership securities. The Board of Supervisors, without the vote or consent of any Limited Partner or any other Person, is authorized to amend this Agreement to reflect the issuance of Units or the creation of any other equity interests or other Partnership securities, and the admission of any Person as a Limited Partner which has received Units or other equity interests or Partnership securities, in accordance with Section 3.4.  All Units shall have identical rights in all respects as all other Units, except in each case as otherwise specified in this Agreement.

Section 3.3. Register.  The register of the Partnership shall be the definitive record of ownership of each Unit and all relevant information with respect to each Partner. Unless the Board of Supervisors shall determine otherwise, Units shall be uncertificated and recorded in the books and records of the Partnership.

9

Section 3.4. Transfer of a Limited Partner Interest.

(a)           Except as part of a division of property under a court order, no Limited Partner may Assign all or any part of its Partnership Interests in the Partnership without the approval of the Board of Supervisors, acting in its sole discretion.

(b)           Notwithstanding clause (a) above, any Limited Partner who is an individual may transfer by way of gift all or any portion of its Partnership Interest to a Family Member of such Partner or to a trust or other entity whose sole and exclusive beneficiaries are such Partner and/or Family Members of such Partner, but only to the extent (A) such transferee executes and delivers to the Partnership an Adoption Agreement for Family Members in the form attached as Exhibit B hereto, and (B) the Board of Supervisors consents to such transfer, which consent shall not be unreasonably withheld.

(c)           Notwithstanding clause (a) above, (i) each Limited Partner (other than Athlon Energy) may transfer its Units or any portion thereof for shares of Common Stock in an Exchange Transaction.

(d)           The Limited Partners agree, upon request of the Board of Supervisors, to execute such certificates or other documents and perform such acts as the Board of Supervisors reasonably deems appropriate to preserve the status of the Partnership as a limited partnership, after the completion of any permitted transfer of an interest in the Partnership, under the laws of the State of Delaware.

(e)           All Net Income and Net Loss of the Partnership attributable to any Partnership Interest acquired by reason of any transfer of such Partnership Interest shall be allocated among the transferor and transferee as if the books of the Partnership were closed on the date of the transfer and (i) in respect of the period ending on or before the date of the transfer, to the transferor and (ii) in respect of the period beginning the day after the date of transfer, to the transferee. All distributions on or before the date of such transfer shall be made to transferor, and all distributions thereafter shall be made to the transferee. The effective date of any transfer permitted under this Agreement shall be the close of business on the day the Partnership is notified of the Transfer.

(f)            The death, retirement, incompetence, bankruptcy, insolvency, liquidation, removal, expulsion or withdrawal of a Limited Partner shall not cause (in and of itself) a dissolution of the Partnership, but the rights of such a Limited Partner to share in the Net Income and Net Loss of the Partnership, to receive distributions and to assign its Partnership Interest pursuant to this Section 3.4, on the happening of such an event, shall devolve on its beneficiary or other successor, executor, administrator, guardian or other legal representative for the purpose of settling its estate or administering its property, and the Partnership shall continue as a limited partnership. Such successor or personal representative, however, shall become a Substituted Limited Partner only upon compliance with the requirements of Article III hereof with respect to a transferee of a Partnership Interest. The estate of a bankrupt Limited Partner shall be liable for all the obligations of the Limited Partner.

(g)           Notwithstanding any contrary provision in this Agreement, in no event may any transfer of a Unit or other Partnership Interest be made by any Limited Partner or assignee or transferee if: (i) such transfer is made to any Person who lacks the legal right, power

10

or capacity to own such Unit or other Partnership Interest; or (ii) such transfer would require the registration of such transferred Unit or other Partnership Interest pursuant to any applicable United States federal or state securities laws (including, without limitation, the Securities Act or the Exchange Act) or other foreign securities laws or would constitute a non-exempt distribution pursuant to applicable state securities laws.

(h)           Spouses.

(i)            As a condition to becoming or remaining a Limited Partner, each Limited Partner that is an individual and is or becomes married, shall cause his or her spouse to execute an agreement in the form of Exhibit C hereof.  If an existing Limited Partner fails to have his or her spouse execute such agreement the Limited Partner shall thereafter lose all their rights hereunder except for the rights of a mere assignee and the Board of Supervisors shall thereafter have all voting rights with respect to his or her interest.

(ii)           Any Partnership Interest held by an individual who has failed to get his or her spouse to execute an agreement in the form of Exhibit C and any Partnership Interest held by a person who is an Assignee other than an approved Family Member (currently in compliance with all conditions of transfer to such Family Member) shall be subject to the option of the Partnership to acquire the Partnership Interest at any time, in whole not in part, for a cash payment in the amount of its fair market value as determined by the Board of Supervisors in its sole discretion.

(iii)          In the event of a property settlement or separation agreement between a Partner and his or her spouse, such Partner shall use his best efforts to assign to his or her spouse only the right to share in profits and losses, to receive distributions, and to receive allocations of income, gain, loss, deduction or credit or similar item to which the Partner was entitled, to the extent assigned.

(iv)          If a spouse or former spouse of a Partner acquires a Partnership Interest in the Partnership as a result of any such proposed settlement or separation agreement, such spouse or former spouse hereby grants, as evidenced by Exhibit C, an irrevocable power of attorney (which shall be coupled with an interest) to the original Partner who held such Partnership Interest to vote or to give or withhold such approval as such original Partner shall himself or herself vote or approve with respect to such matter and without the necessity of the taking of any action by any such spouse or former spouse.  Such power of attorney shall not be affected by the subsequent disability or incapacity of the spouse or former spouse granting such power of attorney.  Furthermore, such spouse or former spouse agrees that the Partnership shall have the option at any time to purchase all, but not less than all, of such Partnership Interest for its fair market value as determined by the Board of Supervisors in its sole discretion.

Section 3.5. Substituted Limited Partners.

(a)           Unless an Assignee becomes a Substituted Limited Partner in accordance with Section 3.5(b), such Assignee shall not be entitled to any of the rights granted to a Limited

11

Partner hereunder, other than the right to receive allocations of income, gain, loss, deduction, credit and similar items and distributions to which the Assigning Limited Partner would otherwise be entitled, to the extent such items are Assigned.

(b)           An Assignee of all or part of a Partnership Interest shall become a Substituted Limited Partner entitled to all the rights of a Limited Partner (relating to the Assigned portion of the Partnership Interest), respectively, if, and only if, (i) the Assigning Limited Partner requests the Assignee be granted such right, (ii) the Board of Supervisors determines to grant such rights, (iii) the Assignee has paid any fees and reimbursed the Partnership for any expenses paid by the Partnership in connection with such transfer and assignment and (iii) the Assignee executes and delivers such instruments (including Exhibit A or Exhibit B, as applicable) in form and substance satisfactory to the Board of Supervisors, as the Board of Supervisors may deem necessary or desirable to effect such substitution.  The Partnership shall be entitled to treat the record owner of any Partnership Interest as the absolute owner thereof in all respects and shall incur no liability for distributions of cash or other property made to such owner until such time as an Assignment of such interest that complies with the terms of this Agreement has been effected.

Section 3.6. No Publicly Traded Partnership.  Notwithstanding the foregoing, without the prior consent of the Board of Supervisors, no Partner shall Dispose of all or any part of its Partnership Interest in such a manner that, after the Disposition, the Partnership would become taxable as a corporation for U.S. federal income tax purposes.

Section 3.7. Splits, Distributions and Reclassifications.  The Partnership shall not in any manner subdivide (by any Unit split, Unit distribution, reclassification, recapitalization or otherwise) or combine (by reverse Unit split, reclassification, recapitalization or otherwise) the outstanding Units unless an identical event is occurring with respect to the Common Stock, in which event the Units shall be subdivided or combined concurrently with and in the same manner as the Common Stock.

Section 3.8. Cancellation of Common Stock and Units.  At any time a share of Common Stock is redeemed, repurchased, acquired, cancelled or terminated by Athlon Energy, one (1) Unit registered in the name of Athlon Energy will automatically be cancelled for no consideration by the Partnership so that the aggregate number of Units held by Athlon Energy at all times equals the number of shares of Common Stock outstanding.

Section 3.9. Incentive Plans.  At any time Athlon Energy issues a share of Common Stock pursuant to an Incentive Plan (whether pursuant to the exercise of a stock option or the grant of a restricted share award or otherwise, provided however that the issuance of a share of Common Stock in connection with a restricted share award shall not be deemed to occur for purposes of this Section 3.9 until such share becomes vested), the following shall occur: (a) Athlon Energy shall be deemed to contribute to the capital of the Partnership an amount of cash equal to the current per share market price of a share of Common Stock on the date such share is issued (or, if earlier, the date the related award under the Incentive Plan is exercised) and the Capital Account of Athlon Energy shall be adjusted accordingly; (b) the Partnership shall be deemed to purchase from Athlon Energy a share of Common Stock for an amount of cash equal to the amount of cash deemed contributed by Athlon Energy to the Partnership in clause (a)

12

above (and such share is deemed delivered to its owner under the Incentive Plan); (c) the net proceeds (including the amount of any payments made on a loan with respect to an Incentive Plan award) received by Athlon Energy with respect to such share, if any, shall be concurrently transferred and paid to the Partnership (and such net proceeds so transferred shall not constitute a capital contribution); and (d) the Partnership shall issue to Athlon Energy one (1) Unit registered in the name of Athlon Energy.

Section 3.10. Offerings of Common Stock.  At any time Athlon Energy issues a share of Common Stock other than pursuant to an Incentive Plan or an Exchange Transaction, the net proceeds or other consideration received by Athlon Energy with respect to such share, if any, shall be concurrently contributed to the Partnership and the Partnership shall issue to Athlon Energy one (1) Unit registered in the name of Athlon Energy; provided, that unless otherwise determined by the Board of Supervisors in its sole discretion, this Section 3.10 shall not apply to any shares of Common Stock issued by Athlon Energy in connection with (a) any direct or indirect business combination or acquisition transaction involving Athlon Energy, (b) any joint venture or strategic partnership entered into by Athlon Energy or (c) to financial institutions, commercial lenders, brokers/finders or any similar party, or to respective designees, in connection with the incurrence or guarantee of indebtedness by Athlon Energy or any of its subsidiaries.  In the event of an issuance of Common Stock, and the contribution of the net proceeds or other consideration from such issuance to the Partnership, the Partnership shall pay Athlon Energy’s expenses associated with such issuance, including any underwriting discounts or commissions (it being understood that payment of some or all of such expenses may be made by Athlon Energy on behalf of the Partnership out of the gross proceeds of such issuance prior to the contribution of such net proceeds or other consideration by Athlon Energy to the Partnership).

ARTICLE IV

CAPITAL COMMITMENTS

Section 4.1. Capital Accounts.

(a)           A Capital Account shall be established and maintained for each Partner in accordance with the provisions of Treasury Regulations Section 1.704-1(b)(2)(iv).  Each Partner has made a capital contribution to the Partnership and owns Units in the amount and designation set forth for such Partner on Schedule A, as the same may be amended from time to time by the Board of Supervisors to the extent necessary to reflect accurately sales, exchanges, conversions or other Transfers, redemptions, capital contributions, the issuance of additional Units or similar events having an effect on a Partner’s ownership of Units.  Except as provided by laws or in Sections 3.10, 8.5 and 11.3, the Partners shall have no obligations or right to make any additional capital contributions or loans to the Partnership.

(b)           Such Capital Account shall be (i) increased by (A) the amount of money contributed by that Partner to the Partnership, (B) the fair market value as of the date of contribution (as determined by the Board of Supervisors) of property contributed by that Partner to the Partnership (net of liabilities secured by the contributed property that the Partnership is considered to assume or take subject to under Code Section 752) and (C) all items of Partnership

13

income and gain (including, without limitation, income and gain exempt from tax) and allocated with respect to such Partnership Interest pursuant to Section 5.1, and (ii) decreased by (A) the amount of money distributed to that Partner by the Partnership, (B) the fair market value as of the date of distribution (as determined by the Board of Supervisors) of property distributed to that Partner by the Partnership (net of liabilities secured by the distributed property that the Partner is considered to assume or take subject to under Code Section 752), and (C) all items of Partnership deduction and loss and allocated with respect to such Partnership Interest pursuant to Section 5.1.  A transferee of a Partnership Interest shall succeed to a pro rata portion of the Capital Account of the transferor relating to the Partnership Interest so transferred.

(c)           The Book Value of Partnership property and the Capital Accounts of the Partners shall be adjusted in the following circumstances:

(i)            Consistent with the provisions of Treasury Regulations Section 1.704-1(b)(2)(iv)(f), upon (A) an issuance of additional Partnership Interests as consideration for cash or contributed property (other than a de minimis amount) following the Effective Date, (B) the distribution by the Partnership to a Partner of more than a de minimis amount of property as consideration for a Partnership Interest following the Effective Date or (C) the issuance of additional Partnership Interests (other than a de minimis interest) as consideration for the provision of services to or for the benefit of the Partnership by an existing Partner acting in a partner capacity, or by a new Partner acting in a partner capacity or in anticipation of being a Partner, the Capital Accounts of all Partners and the Book Value of each Partnership property immediately prior to such issuance shall be adjusted upward or downward to reflect any Unrealized Gain or Unrealized Loss attributable to such Partnership property, as if such Unrealized Gain or Unrealized Loss had been recognized on an actual sale of each such property immediately prior to such issuance or distribution and had been allocated to the Partners at such time pursuant to Section 5.1; provided, that adjustment pursuant to clauses (A), (B) and (C) above shall be made only if the Board of Supervisors reasonably determines that such adjustments are necessary or appropriate to reflect the relative economic interests of the Partners.

(ii)           In accordance with Treasury Regulations Section 1.704-1(b)(2)(iv)(f), immediately prior to any actual or deemed distribution to a Partner of any Partnership property following the Effective Date (other than a distribution solely of cash that is not in redemption or retirement of a Partnership Interest), the Capital Accounts of all Partners and the Book Value of such Partnership property shall be adjusted upward or downward to reflect any Unrealized Gain or Unrealized Loss attributable to such Partnership property, as if such Unrealized Gain or Unrealized Loss had been recognized in a sale of such property immediately prior to such distribution for an amount equal to its fair market value, and had been allocated to the Partners, at such time, pursuant to Section 5.1.

(d)           Capital Accounts shall be adjusted, in a manner consistent with this Section 4.1, to reflect any adjustments in items of the Partnership’s income, gain, loss or deduction that result from amended returns filed by the Partnership or pursuant to an agreement by the Partnership with the Internal Revenue Service or a final court decision.

14

Section 4.2. Return of Contributions.  An unrepaid Capital Contribution is not a liability of the Partnership or of any other Partner.  A Partner is not required to contribute or to lend any cash or property to the Partnership to enable the Partnership to return any other Partner’s Capital Contributions.

Section 4.3. Advances by Partners.  If the Partnership does not have sufficient cash to pay its obligations, with the approval of the Board of Supervisors, the General Partner or any of the Limited Partners may (but shall have no obligation to) advance all or part of the needed funds to or on behalf of the Partnership, which advance shall constitute a loan from such Partner to the Partnership, shall bear interest at the rate determined by the Board of Supervisors in this sole discretion from the date of the advance until the date of payment, and shall not be a Capital Contribution.  Any advance made by the General Partner or any of the Limited Partners shall be repaid by the Partnership prior to any distributions under Sections 5.3.

ARTICLE V

ALLOCATIONS AND DISTRIBUTIONS

Section 5.1. Allocations for Capital Account Purposes.  For purposes of maintaining the Capital Accounts and in determining the rights of the Partners among themselves, the Partnership’s items of income, gain, loss and deduction shall be allocated among the Partners in each taxable year (or portion thereof) as provided hereinbelow.

(a)           Net Income and Net Loss.  After giving effect to the special allocations set forth in Section 5.1(b), Net Income and Net Loss for each taxable period (and all items of income, gain, loss and deduction taken into account in computing Net Income or Net Loss for such taxable period) shall be allocated to the Partners as follows:

(i)            Net Income for each taxable period shall be allocated as follows:

(A)          First, to the General Partner until the aggregate Net Income allocated to the General Partner pursuant to this Section 5.1(a)(i)(A) for the current and each prior taxable year is equal to the Net Loss allocated to the General Partner pursuant to Section 5.1(a)(ii)(B) during all prior periods; and

(B)          Second, to the Partners in accordance with their Percentage Interests.

(ii)           Net Loss for each taxable period shall be allocated as follows:

(A)          First, to the Partners in accordance with their Percentage Interests until the Adjusted Capital Account of each Partner is reduced to zero; and

(B)          Second, 100% to the General Partner.

(b)           Special Allocations.  Notwithstanding any other provision of this Section 5.1, the following special allocations shall be made for such taxable period:

15

(i)            Partnership Minimum Gain Chargeback.  Notwithstanding any other provision of this Section 5.1, if there is a net decrease in Partnership Minimum Gain during any Partnership taxable period, each Partner shall be allocated items of Partnership income and gain for such period (and, if necessary, subsequent periods) in the manner and amounts provided in Treasury Regulations Sections 1.704-2(f)(6), 1.704-2(g)(2) and 1.704-2(j)(2)(i).  For purposes of this Section 5.1(b), each Partner’s Adjusted Capital Account balance shall be determined, and the allocation of income or gain required hereunder shall be effected, prior to the application of any other allocations pursuant to this Section 5.1(b) with respect to such taxable period (other than allocations pursuant to Sections 5.1(b)(v) and 5.1(b)(vi)).  This Section 5.1(b)(i) is intended to comply with the “partnership minimum gain chargeback” requirement in Treasury Regulations Section 1.704-2(f) and shall be interpreted consistently therewith

(ii)           Chargeback of Partner Nonrecourse Debt Minimum Gain.  Notwithstanding the other provisions of this Section 5.1 (other than Section 5.1(b)(i)), except as provided in Treasury Regulations Section 1.704-2(i)(4), if there is a net decrease in Partner Minimum Gain during any Partnership taxable period, any Partner with a share of such Partner Minimum Gain at the beginning of such taxable period shall be allocated items of Partnership income and gain for such period (and, if necessary, subsequent periods) in the manner and amounts provided in Treasury Regulations Sections 1.704-2(i)(4) and 1.704-2(j)(2)(ii).  For purposes of this Section 5.1(b), each Partner’s Adjusted Capital Account balance shall be determined, and the allocation of income or gain required hereunder shall be effected, prior to the application of any other allocations pursuant to this Section 5.1(b), other than Sections 5.1(b)(i), 5.1(b)(v) and 5.1(b)(vi), with respect to such taxable period.  This Section 5.1(b)(ii) is intended to comply with the chargeback of items of income and gain requirement in Treasury Regulations Section 1.704-2(i)(4) and shall be interpreted consistently therewith.

(iii)          Qualified Income Offset.  In the event any Partner unexpectedly receives any adjustments, allocations or distributions described in Treasury Regulations Sections 1.704-1(b)(2)(ii)(d)(4), 1.704-1(b)(2)(ii)(d)(5), or 1.704-1(b)(2)(ii)(d)(6), items of Partnership income and gain shall be specially allocated to such Partner in an amount and manner sufficient to eliminate, to the extent required by the Treasury Regulations promulgated under Section 704(b) of the Code, the deficit balance, if any, in its Adjusted Capital Account created by such adjustments, allocations or distributions as quickly as possible unless such deficit balance is otherwise eliminated pursuant to Sections 5.1(b)(i) or (ii); provided that an allocation pursuant to this Section 5.1(b)(iii) shall be made only if and to the extent that such Partner would have a deficit balance in its Adjusted Capital Account after all other allocations provided for in this Section 5.1 have been tentatively made as if this Section 5.1(b)(iii) were not in this Agreement.

(iv)          Gross Income Allocations.  In the event any Partner has a deficit balance in its Adjusted Capital Account (determined without regard to Subdivision (ii) of the definition of Adjusted Capital Account) at the end of any Partnership taxable period, such Partner shall be specially allocated items of Partnership gross income and gain in the amount of such excess as quickly as possible; provided, that an allocation pursuant to this Section 5.1(b)(iv) shall be made only if and to the extent that such Partner would have a

16

deficit balance in its Adjusted Capital Account (as so determined) after all other allocations provided for in this Section 5.1 have been tentatively made as if this Section 5.1(b)(iv) and Section 5.1(b)(iii) were not in this Agreement.

(v)           Partnership Nonrecourse Deductions.  Partnership Nonrecourse Deductions for any taxable period shall be allocated to the Partners in accordance with their respective Percentage Interests.

(vi)          Partner Nonrecourse Deductions.  Partner Nonrecourse Deductions for any taxable period shall be allocated 100% to the Partner that bears the Economic Risk of Loss with respect to the Partner Nonrecourse Debt to which such Partner Nonrecourse Deductions are attributable in accordance with Treasury Regulations Section 1.704-2(i).  If more than one Partner bears the Economic Risk of Loss with respect to a Partner Nonrecourse Debt, such Partner Nonrecourse Deductions attributable thereto shall be allocated between or among such Partners in accordance with the ratios in which they share such Economic Risk of Loss.

(vii)         Partnership Nonrecourse Liabilities.  For purposes of Treasury Regulations Section 1.752-3(a)(3), Partnership Nonrecourse Liabilities shall be allocated among the Partners in accordance with their respective Percentage Interests.

(viii)        Limitations on Deductions.  Notwithstanding the provisions of paragraph (a) above, no allocation of Net Loss or item of loss or deduction (other than an allocation of Partner Nonrecourse Deductions or Partnership Nonrecourse Deductions) shall be made to a Limited Partner to the extent such allocation would cause or increase a deficit balance in such Partner’s capital account.  Such loss or deduction instead shall be allocated to the General Partner.  For purposes of this paragraph the capital accounts of the Partners shall be reduced for any adjustment, allocation or distribution described in Treas. Reg. § 1.704-1(b)(2)(ii)(d)(4), (5) or (6).

(ix)          Curative Allocation

(A)          The Required Allocations shall be taken into account in making the Agreed Allocations so that, to the extent possible, the net amount of items of income, gain, loss and deduction allocated to each Partner pursuant to the Required Allocations and the Agreed Allocations, together, shall be equal to the net amount of such items that would have been allocated to each such Partner under the Agreed Allocations had the Required Allocations and the related Curative Allocation not otherwise been provided in this Section 5.1.  Allocations pursuant to this Section 5.1(b)(ix)(A) shall only be made with respect to Required Allocations to the extent the Board of Supervisors reasonably determines that such allocations will otherwise be inconsistent with the economic agreement among the Partners.

(B)          The Board of Supervisors shall have reasonable discretion, with respect to each taxable period, to (1) apply the provisions of Section 5.1(b)(ix)(A) in whatever order is most likely to minimize the economic

17

distortions that might otherwise result from the Required Allocations and (2) divide all allocations pursuant to Section 5.1(b)(ix)(A) among the Partners in a manner that is likely to minimize such economic distortions.

(x)           Code Section 754 Adjustments.  To the extent an adjustment to the adjusted tax basis of any Partnership asset pursuant to Section 734(b) or 743(b) of the Code is required, pursuant to Treasury Regulations Section 1.704-1(b)(2)(iv)(m), to be taken into account in determining Capital Accounts, the amount of such adjustment to the Capital Accounts shall be treated as an item of gain (if the adjustment increases the basis of the asset), or loss (if the adjustment decreases such basis), and such item of gain or loss shall be specially allocated to the Partners in a manner consistent with the manner in which their Capital Accounts are required to be adjusted pursuant to such Section of the Treasury Regulations.

(c)           Simulated Depletion with respect to each separate oil and gas property shall be allocated to the Partners in the same proportion that the Partners (or their predecessors in interest) were allocated the adjusted tax basis of such property under Section 5.2(b).

(d)           Special Rules.  It is intended that (i) the Capital Accounts be maintained at all times in accordance with Section 704 of the Code and applicable Regulations, (ii) the Capital Accounts shall be increased or decreased by any items required by the Regulations under section 704(b) of the Code to increase or decrease, respectively, a Partner’s Capital Account, and (iii) the provisions hereof relating to the Capital Accounts be interpreted in a manner consistent therewith.  The Board of Supervisors shall be authorized to make appropriate amendments to the allocations of items pursuant to this Section 5.1 if necessary in order to comply with Section 704 of the Code or applicable Regulations thereunder or to effect the terms, purposes and conditions of this Agreement; provided, however, that no such change shall have a material adverse effect upon the amount distributable to any Partner hereunder.

Section 5.2. Allocations for Tax Purposes.

(a)           Except as otherwise provided herein, for federal income tax purposes, (i) each item of income, gain, loss and deduction shall be allocated among the Partners in the same manner as its correlative item of “book” income, gain, loss or deduction is allocated pursuant to Section 5.1, and (ii) each tax credit shall be allocated to the Partners in the same manner as the receipt or expenditure giving rise to such credit is allocated pursuant to Section 5.1.

(b)           The deduction for depletion with respect to each separate oil and gas property (as defined in Section 614 of the Code) shall, in accordance with Section 613A(c)(7)(D) of the Code, be computed for federal income tax purposes separately by the Partners rather than the Partnership.  Except as provided in Section 5.2(d), for purposes of such computation, the proportionate share of the adjusted tax basis of each oil and gas property shall be allocated among the Partners in accordance with their Percentage Interests.  Each Partner, with the assistance of the Board of Supervisors, shall separately keep records of its share of the adjusted tax basis in each separate oil and gas property, adjust such share of the adjusted tax basis for any cost or percentage depletion allowable with respect to such property and use such adjusted tax basis in the computation of its cost depletion or in the computation of its gain or loss on the

18

disposition of such property by the Partnership.  Upon the request of the Board of Supervisors, each Limited Partner shall advise the Board of Supervisors of its adjusted tax basis in each separate oil and gas property and any depletion computed with respect thereto, both as computed in accordance with the provisions of this subsection.  The Board of Supervisors may rely on such information and, if it is not provided by the Limited Partner, may make such reasonable assumptions as it shall determine with respect thereto.

(c)           Except as provided in Section 5.2(d), for the purposes of the separate computation of gain or loss by each Partner on the sale or disposition of each separate oil and gas property (as defined in Section 614 of the Code), the Partnership’s allocable share of the “amount realized” (as such term is defined in Section 1001(b) of the Code) from such sale or disposition shall be allocated for federal income tax purposes among the Partners as follows:

(i)            first, to the extent such amount realized constitutes a recovery of the Simulated Basis of the property, to the Partners in the same percentages as the depletable basis of such property was allocated to the Partners pursuant to Section 5.2(b);

(ii)           second, the remainder of such amount realized, if any, to the Partners so that, to the maximum extent possible, the total amount realized allocated to each Partner under this Section 5.2(c) will equal such Partner’s share of the proceeds derived by the Partnership from such sale or disposition.

(d)           In accordance with Section 704(c) of the Code and the applicable Treasury Regulations thereunder, income, gain, loss, and deduction with respect to any property contributed to the Partnership shall, solely for tax purposes, be allocated among the Partners so as to take account of any variation between the adjusted basis of such property to the Partnership for federal income tax purposes and its initial Book Value.  In the event the Book Value of any property is adjusted pursuant to Section 4.1(c), subsequent allocations of income, gain, loss, and deduction with respect to such property shall take account of any variation between the adjusted basis of such property for federal income tax purposes and its Book Value in the same manner as under Code Section 704(c) and the applicable Regulations thereunder.  For purposes of this applying this Section 5.2(d), the Board of Supervisors shall apply any reasonable method under Treasury Regulation Section 1.704-3.

(e)           Any gain allocated to the Partners upon the sale or other taxable disposition of any Partnership asset shall, to the extent possible, after taking into account other required allocations of gain pursuant to this Section 5.2, be characterized as Recapture Income in the same proportions and to the same extent as such Partners (or their predecessors in interest) have been allocated any deductions directly or indirectly giving rise to the treatment of such gains as Recapture Income.

(f)            All items of income, gain, loss, deduction and credit recognized by the Partnership for federal income tax purposes and allocated to the Partners in accordance with the provisions hereof shall be determined without regard to any election under Section 754 of the Code which may be made by the Partnership; provided, however, that such allocations, once made, shall be adjusted as necessary or appropriate to take into account those adjustments permitted or required by Sections 734 and 743 of the Code.

19

Section 5.3. Distributions.  The Partnership will distribute such amounts as may be determined from time-to-time by the Board of Supervisors in its sole discretion.  Notwithstanding the foregoing, the Partnership shall make quarterly distributions of available cash, if any, to the Limited Partners in such amounts as the Board of Supervisors determines in its sole discretion are sufficient to satisfy each Limited Partner’s projected deemed income tax liability with respect to its Partnership Interests.  The Board of Supervisors will make its determination as to each Partner individually.

ARTICLE VI

MANAGEMENT AND OPERATIONS OF THE PARTNERSHIP

Section 6.1. Management Generally.  In order to enable the Board of Supervisors to manage the business and affairs of the Partnership, the General Partner hereby irrevocably delegates to the Board of Supervisors all management powers over the business and affairs of the Partnership that it may now or hereafter possess under applicable law (other than its obligations as “tax matters partner” under Section 8.3 of this Agreement) as permitted under Section 17-403(c) of the Act.  The General Partner further agrees to take any and all action necessary and appropriate, in the sole discretion of the Board of Supervisors, to effect any duly authorized actions by the Board of Supervisors or any Officer, including executing or filing any agreements, instruments or certificates, delivering all documents, providing all information and taking or refraining from taking action as may be necessary or appropriate to achieve all the effective delegation of power described in this Section.  Each of the Partners and Assignees and each Person who may acquire an interest in a Partnership Interest hereby approves, consents to, ratifies and confirms such delegation.  The delegation by the General Partner to the Board of Supervisors of management powers over the business and affairs of the Partnership pursuant to the provisions of this Agreement shall not cause the General Partner to cease to be a general partner of the Partnership nor shall it cause the Board of Supervisors or any member thereof to be a general partner of the Partnership or to have or be subject to the liabilities of a general partner of the Partnership.  Except as provided in Section 8.3 of this Agreement relating to the General Partner’s duties as “tax matters partner” and except as otherwise provided in this Agreement, the management of the Partnership shall be vested exclusively in the Board of Supervisors and, subject to the direction of the Board of Supervisors, the Officers.  Neither the General Partner nor any of the Limited Partners in their capacities as such shall have any part in the management of the Partnership (except, with respect to the General Partner, as provided in Section 8.3 of this Agreement relating to its duties as “tax matters partner”) and shall have no authority or right to act on behalf of the Partnership or deal with any third parties on behalf of the Partnership in connection with any matter, except as requested or authorized by the Board of Supervisors.

Section 6.2. Reserved.

Section 6.3. The Board of Supervisors.

(a)           Composition.  The Board of Supervisors shall consist of not less than two (2) individuals appointed by the General Partner.  Members of the Board of Supervisors shall

20

serve until they resign or are removed by the General Partner.  Any vacancies shall be filled by appointment by the General Partner.

(b)           Voting; Quorum.  Each member of the Board of Supervisors shall have one vote.  Unless otherwise specified in this Agreement, the vote of the majority of the members of the Board of Supervisors present at a meeting in which a quorum is present shall be the act of the Board of Supervisors.  A majority of the number of members of the Board of Supervisors then in office shall constitute a quorum for the transaction of business at any meeting of the Board of Supervisors, but if less than a quorum is present at a meeting, a majority of the members of the Board of Supervisors present at such meeting may adjourn the meeting from time to time, without notice other than announcement at the meeting, until a quorum shall be present.

(c)           Meetings.  Regular meetings of the Board of Supervisors shall be held at such times and places as shall be designated from time to time by resolution of the Board of Supervisors.  Special meetings of the Board of Supervisors may be called by request of any member of the Board of Supervisors or by the General Partner.  Members of the Board of Supervisors may participate in and hold a meeting by means of conference telephone, video conference or similar communications equipment by means of which all Supervisors participating in the meeting can hear each other, and participation in such meetings shall constitute presence in person at the meeting.

(d)           Proxies.  A member of the Board of Supervisors may vote at any meeting by a written proxy executed by such member and delivered to another member.  A proxy shall be revocable unless it is stated to be irrevocable.

(e)           Action Without a Meeting.  Any action required or permitted to be taken at a meeting of the Board of Supervisors, may be taken without a meeting and without a vote if a consent or consents in writing, setting forth the action so taken, is signed by members of the Board of Supervisors having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all members of the Board of Supervisors entitled to vote thereon were present and voted.

(f)            Compensation.  Members of the Board of Supervisors shall receive no compensation.

Section 6.4. Officers.

(a)           Generally.  The Board of Supervisors shall appoint such agents of the Partnership, referred to as “Officers” of the Partnership, as are desired.  An Officer may but need not be a member of the Board of Supervisors.  Any number of offices may be held by the same person.  The election or appointment of an Officer shall not of itself create contractual rights.

(b)           Authority.  Officers shall have the powers and duties defined in the resolutions appointing them including, to the extent so provided, the authority to exercise the power of the Board of Supervisors in the management of the Partnership.

21

(c)           Removal.  The Board of Supervisors may, in its sole discretion, remove any Officer with or without cause at any time.

(d)           Delegation of Authority.  Unless otherwise provided by resolution of the Board of Supervisors, no Officer shall have the power or authority to delegate to any Person such Officer’s rights and powers as an Officer to manage the business and affairs of the Partnership.

(e)           Compensation.  The Officers shall receive such compensation for their services as may be approved by the Board of Supervisors.

(f)            Powers of Attorney.  The Partnership may grant powers of attorney or other authority as appropriate to establish and evidence the authority of the Officers and other Persons.

Section 6.5. Reserved.

Section 6.6. Resolution of Conflicts of Interest by the Board of Supervisors.

(a)           Unless otherwise expressly provided in this Agreement, whenever a potential conflict of interest exists or arises between the General Partner or any of its Affiliates, or any Officer or member of the Board of Supervisors, on the one hand, and the Partnership, any Partner or any Assignee, on the other hand, any resolution or course of action in respect of such conflict of interest shall be permitted and deemed approved by all Partners, and shall not constitute a breach of this Agreement, of any agreement contemplated herein, or of any standard of care or duty stated or implied by law or equity, if the resolution or course of action is or, by operation of this Agreement is deemed to be, fair and reasonable to the Partnership.  Any conflict of interest and any resolution of such conflict of interest shall be conclusively deemed fair and reasonable to the Partnership if such conflict of interest or resolution is (i) on terms no less favorable to the Partnership than those generally being provided to or available from unrelated third parties or (ii) fair to the Partnership, taking into account the totality of the relationships between the parties involved (including other transactions that may be particularly favorable or advantageous to the Partnership).  The Board of Supervisors shall be authorized in connection with its determination of what is “fair and reasonable” to the Partnership and in connection with its resolution of any conflict of interest to consider (i) the relative interests of any party to such conflict, agreement, transaction or situation and the benefits and burdens relating to such interest; (ii) any customary or accepted industry practices and any customary or historical dealings with a particular Person; (iii) any applicable generally accepted accounting or engineering practices or principles; and (iv) such additional factors as the Board of Supervisors determines in its sole discretion to be relevant, reasonable or appropriate under the circumstances.  Nothing contained in this Agreement, however, is intended to nor shall it be construed to require the Board of Supervisors to consider the interest of any Person other than the Partnership.  In the absence of bad faith by the Board of Supervisors, the resolution, action or terms so made, taken or provided by the Board of Supervisors with respect to such matter shall not constitute a breach of this Agreement or any other agreement contemplated herein or a breach of any standard of care or duty stated or implied by law or equity.

22

(b)           Whenever this Agreement or any other agreement contemplated hereby provides that the Board of Supervisors is permitted or required to make a decision (i) in its “sole discretion” or “discretion,” that it deems “necessary or appropriate” or under a grant of similar authority or latitude, the Board of Supervisors shall be entitled to consider only such interests and factors as it desires and shall have no duty or obligation to give any consideration to any interest of, or factors affecting, the Partnership, any Partner or any Assignee, (ii) it will make such decision in good faith unless another express standard is provided for, or (iii) in “good faith” or under another express standard, the Board of Supervisors shall act under such express standard and shall not be subject to any other or different standards imposed by this Agreement or any other agreement contemplated hereby or under the Act or any other law, rule or regulation.

(c)           Whenever a particular transaction, arrangement or resolution of a conflict of interest is required under this Agreement to be “fair and reasonable” to any Person, the fair and reasonable nature of such transaction, arrangement or resolution shall be considered in the context of all similar or related transactions.

(d)           Notwithstanding the foregoing, the Exchange Agreement and the Tax Receivable Agreement shall be deemed permitted under this Section 6.6.

Section 6.7. Other Matters Concerning the Board of Supervisors.

(a)           The Board of Supervisors may rely and shall be protected in acting or refraining from acting upon any resolution, certificate, statement, instrument, opinion, report, notice, request, consent, order, bond, debenture, or other paper or document believed by it to be genuine and to have been signed or presented by the proper party or parties.

(b)           The Board of Supervisors may consult with legal counsel, accountants, appraisers, management consultants, investment bankers and other consultants and advisers selected by it, and any act taken or omitted to be taken in reliance upon the opinion (including, without limitation, an opinion of counsel) of such Persons as to matters that such Board of Supervisors reasonably believes to be within such Person’s professional or expert competence shall be conclusively presumed to have been done or omitted in good faith and in accordance with such opinion.

(c)           Any standard of care and any duty imposed by this Agreement or stated or implied by law or equity shall be modified, waived or limited as required to permit the Board of Supervisors to act under this Agreement or any other agreement contemplated by this Agreement and to make any decision pursuant to the authority prescribed in this Agreement so long as such action is reasonably believed by the Board of Supervisors to be in, or not inconsistent with, the best interests of the Partnership.

Section 6.8. Reliance by Third Parties.  Notwithstanding anything to the contrary in this Agreement, Persons dealing with the Partnership are entitled to rely conclusively upon the power and authority of the Board of Supervisors.  Any Officer of the Partnership authorized by the Board of Supervisors to act on behalf and in the name of the Partnership with respect to the relevant matter shall have full power and authority to encumber, sell or otherwise use in any

23

manner any and all assets of the Partnership and to enter into any contracts on behalf of the Partnership.  Any Person dealing with the Partnership shall be entitled to deal with the Board of Supervisors or any Officer of the Partnership authorized by the Board of Supervisors to act on behalf and in the name of the Partnership with respect to the relevant matter as if it were the Partnership’s sole party in interest, both legally and beneficially.  Each and every certificate, document or other instrument executed on behalf of the Partnership by the Board of Supervisors or any Officer of the Partnership authorized by the Board of Supervisors to act on behalf and in the name of the Partnership with respect to such matter shall be conclusive evidence in favor of any and every Person relying thereon that (a) at the time of the execution and delivery of such certificate, document or instrument, this Agreement was in full force and effect and (b) such certificate, document or instrument was duly executed and delivered in accordance with the terms and provisions of this Agreement and is binding upon the Partnership.

Section 6.9. Reserved.

Section 6.10. Reserved.

Section 6.11. Reserved.

Section 6.12. Grant of Authority.  Each Partner hereby irrevocably constitutes and appoints each member of the Board of Supervisors with full power of substitution, each as its true and lawful attorney and agent, in its name, place and stead to make, execute, acknowledge and, if necessary, to file and record:

(a)           any certificates or other instruments or amendments thereof which the Partnership may be required to file under the Act or any other laws of the State of Delaware or pursuant to the requirements of any governmental authority having jurisdiction over the Partnership or which the Board of Supervisors shall deem it advisable to file, including, without limitation, this Agreement, any amended Agreement or certificate of cancellation;

(b)           any certificates or other instruments (including counterparts of this Agreement with such changes as may be required by the law of other jurisdictions) and all amendments thereto which the Board of Supervisors deems appropriate or necessary to qualify, or continue the qualification of, the Partnership as a limited partnership;

(c)           any certificates or other instruments which may be required in order to effectuate the dissolution and termination of the Partnership pursuant to Article XI; and

(d)           any amendment to any certificate or to this Agreement necessary to reflect any other changes made pursuant to the exercise of the powers of attorney contained in this Section 6.12 or pursuant to this Agreement.

Section 6.13. Costs and Expenses and Compensation.  The Partnership shall (i) pay or cause to be paid all reasonable costs and expenses of the Partnership incurred in pursuing and conducting, or otherwise related to, the business of the Partnership, including in connection with the IPO and any subsequent action taken by the General Partner with respect to the business of the Partnership, and (ii) reimburse the General Partner for any reasonable out-of-pocket costs and expenses reasonably incurred by it in connection therewith (including, without limitation, in the

24

performance of its duties as tax matters partner). The General Partner shall be entitled to reimbursement of all of its expenses attributable to the performance of its obligations hereunder. Subject to the Act, no amount so paid shall be deemed to be a distribution of Partnership assets for purposes of this Agreement. Except for reimbursement of expenses, the General Partner shall not receive any compensation for its services as such.

ARTICLE VII

RIGHTS OF PARTNERS

Section 7.1. Access to Information.  In addition to the other rights specifically set forth in this Agreement, each Limited Partner shall have access to all information to which a Partner is entitled to have access pursuant to Section 17-305(a) of the Act.

Section 7.2. Reserved.

Section 7.3. Confidentiality.  The Partnership agrees to provide the Partners valuable confidential and proprietary information of the Partnership, of other Partners and their Affiliates and of third parties who have supplied such information to the Partnership.  In consideration of such confidential information and other valuable consideration provided hereunder, each of the Partners agrees to abide by this Section 7.3.  Unless the Board of Supervisors agrees otherwise, each Partner shall hold in strict confidence any information such Partner receives regarding the Partnership, the General Partner, any other Partner, or their respective Affiliates, whether such information is received from the Partnership, its Affiliates, the other Partners or their respective Affiliates or another Person; provided, however, that such restrictions shall not apply to (a) information that is or becomes available to the public generally without breach of this Section 7.3; (b) disclosures required to be made by applicable laws and regulations or stock exchange requirements or requirements of the Financial Industry Regulatory Authority; (c) disclosures required to be made pursuant to an order, subpoena or other legal process; (d) disclosures to officers, directors or Affiliates of such Partner (and the officers and directors of such Affiliates), to auditors, counsel, and other professional advisors to or potential financing sources of such Persons or the Partnership and to Persons who are direct or indirect beneficial owners of interests in the Partnership and their representatives (provided, however, that such Persons have been informed of the confidential nature of the information, and, in any event, the Partner disclosing such information shall be liable for any failure by such Persons to abide by the provisions of this Section 7.3); (e) disclosures in connection with any litigation or dispute among the Partners and/or the Partnership; or (f) disclosures made by a Partner acting in accordance with the provision regarding confidentiality of certain information of an applicable employment agreement that is then in effect; provided further that any disclosure pursuant to clause (b), (c), (d), (e) or (f) of this sentence shall be made only subject to such procedures as the Partner making such disclosure determines in good faith are reasonable and appropriate in the circumstances, taking into account the need to maintain the confidentiality of such information and the availability, if any, of procedures under laws, regulations, orders, subpoenas, or other legal processes.  Each Partner shall notify the General Partner immediately upon becoming aware of any order, subpoena, or other legal process providing for the disclosure or production of information subject to the provisions of the immediately preceding sentence and, to the extent not prohibited by applicable law, immediately shall supply the General Partner with a copy of

25

any such order, subpoena, or other legal process.  In addition, each Partner shall notify the General Partner prior to disclosing or producing any information subject to the provisions of the two immediately preceding sentences and, to the extent not prohibited by applicable law, shall permit the General Partner to seek a protective order protecting the confidentiality of such information.  The obligations of a Partner pursuant to this Section 7.3 shall continue following the time such Person ceases to be a Partner, but thereafter such Person shall not have the right to enforce the provisions of this Agreement.  Each Partner acknowledges that disclosure of information in violation of the provisions of this Section 7.3 may cause irreparable injury to the Partnership and the Partners for which monetary damages are inadequate, difficult to compute, or both.  Accordingly, each Partner agrees that its obligations under this Section 7.3 may be enforced by specific performance and that breaches or prospective breaches of this Section 7.3 may be enjoined.

Section 7.4. Liability to Third Parties.  No Limited Partner or member of the Board of Supervisors shall have any personal liability for any obligations or liabilities of the Partnership, whether such obligations or liabilities arise in contract, tort or otherwise, except to the extent that any such obligations or liabilities are expressly assumed in writing by such Limited Partner or member of the Board of Supervisors and except as otherwise provided in this Agreement.  Any action taken by any member of the Board of Supervisors who is also a Limited Partner shall not be deemed to be participation in the control of the business of the Partnership by a limited partner of the Partnership within the meaning of Section 17-303(a) of the Act and shall not affect, impair or eliminate the limitations on the liability of Limited Partners or Assignees under this Agreement.

ARTICLE VIII

TAXES

Section 8.1. Tax Returns.  The Board of Supervisors shall cause to be prepared and filed all necessary federal and state income tax returns for the Partnership, including making the elections described in Section 8.2.  Each other Partner shall furnish to the Board of Supervisors all pertinent information in its possession relating to Partnership operations that is necessary to enable the Partnership’s income tax returns to be prepared and filed.  The Board of Supervisors shall prepare all federal and state tax returns on a timely basis.  The Board of Supervisors shall furnish to each Partner copies of all returns that are actually filed promptly after their filing.

Section 8.2. Tax Elections.  The Partnership shall make the following elections on the appropriate tax returns:

(a)           to adopt the calendar year as the Partnership’s fiscal year, unless otherwise required by the Code;

(b)           to adopt the cash or accrual method of accounting, as determined by the Board of Supervisors, and to keep the Partnership’s books and records on the income-tax method;

26

(c)           if a distribution of Partnership property as described in Section 734 of the Code occurs or if a transfer of a Partnership Interest as described in Section 743 of the Code occurs, on request by notice from the Limited Partners, to elect, pursuant to Section 754 of the Code, to adjust the basis of Partnership properties;

(d)           to elect to amortize the start-up expenses of the Partnership ratably over a period of 180 months as permitted by Section 709(b) of the Code; and

(e)           any other election the Board of Supervisors may deem appropriate and in the best interests of the Partners.

It is the intent of the Partners that the Partnership be treated as a partnership for federal income tax purposes and, to the extent permitted by applicable law, for state and local franchise and income tax purposes.  Neither the Partnership nor any Partner may make an election for the Partnership to be excluded from the application of the provisions of subchapter K of chapter 1 of subtitle A of the Code or any similar provisions of applicable state or local law, and no provision of this Agreement shall be construed to sanction or approve such an election.

Section 8.3. Tax Matters Partner.  The General Partner shall be the “tax matters partner” of the Partnership pursuant to Section 6231(a)(7) of the Code.  The tax matters partner shall take such action as may be necessary to cause each other Partner to become a “notice partner” within the meaning of Section 6231(a)(8) of the Code.  The tax matters partner may not take any action contemplated by Sections 6222 through 6231 of the Code without the consent of the Limited Partners representing a majority of the Percentage Interests, but this sentence does not authorize the tax matters partner to take any action left to the determination of an individual Limited Partner under Sections 6222 through 6231 of the Code; provided, however, that the tax matters partner shall not consent to an extension of the statute of limitations for a Partnership taxable year without the consent of the Board of Supervisors.

Section 8.4. Tax Matters.  In exercising their discretion pursuant to this Article VIII or otherwise in regard to matters pertaining to taxes, the Partnership (through the Board of Supervisors) and the General Partner shall fairly take into account the interests of all Partners, and shall not be obligated to take into account the specific interests or circumstances of any particular partner or group of partners.

Section 8.5. Withholding Taxes.

(a)           Notwithstanding any other provision of this Agreement, (i) each Partner hereby authorizes the Partnership to withhold and to pay over, or otherwise pay, any withholding or other taxes payable by the Partnership or any of its Affiliates with respect to such Partner or as a result of such Partner’s participation in the Partnership and (ii) if and to the extent that the Partnership shall be required to withhold or pay any such taxes (including any amounts withheld from amounts payable to the Partnership to the extent attributable, in the judgment of the Board of Supervisors, to the interest of such Partner in the Partnership), such Partner shall be deemed for all purposes of this Agreement to have received a payment from the Partnership as of the time such withholding or tax is required to be paid, which payment shall be deemed to be a distribution with respect to such Partner’s interest in the Partnership.  To the extent that the

27

aggregate of such payments to a Partner for any period exceeds the distributions to which such Partner is entitled for such period, such Partner shall make a prompt payment to the Partnership of such amount.

(b)           If the Partnership makes a distribution in kind and such distribution is subject to withholding or other taxes payable by the Partnership on behalf of any Partner, such Partner shall make a prompt payment to the Partnership of the amount of such withholding or other taxes by wire transfer.

ARTICLE IX

BOOKS, RECORDS, REPORTS, AND BANK ACCOUNTS

Section 9.1. Maintenance of Books.  The books of account for the Partnership shall be located at the principal office of the Partnership or such other place as the Board of Supervisors may deem appropriate, and shall be maintained on an accrual basis in accordance with the terms of this Agreement, except that the capital accounts of the Partners shall be maintained in accordance with Article IV.  The calendar year shall be the accounting year of the Partnership.

Section 9.2. Bank Accounts.  The Board of Supervisors shall cause the Partnership to establish and maintain one or more separate bank and investment accounts for Partnership funds in the Partnership name with such financial institutions and firms as the Board of Supervisors may select and designate signatories thereon.

ARTICLE X

WITHDRAWAL OF GENERAL PARTNER

Section 10.1. Withdrawal of General Partner.  Except as required by law or pursuant to dissolution of the Partnership pursuant to Section 11.1, merger or sale of all of the assets of the Partnership pursuant to Section 11.2 or liquidation or termination of the Partnership pursuant to Section 11.3, the General Partner agrees not to resign or withdraw from the Partnership.

ARTICLE XI

DISSOLUTION, MERGER, LIQUIDATION AND TERMINATION

Section 11.1. Dissolution.  Except as provided in Section 11.3 hereof, the Partnership shall dissolve and its affairs shall be wound up upon the first to occur of either (a) the written determination by the Board of Supervisors or (b) the occurrence of any other event causing dissolution of the Partnership under the Act.

Notwithstanding the foregoing, upon dissolution pursuant to subsection (b) of this Section 11.1, Limited Partners representing a majority of the Percentage Interests may elect to continue the business of the Partnership by adopting a resolution to that effect within 90 days of the occurrence of the event causing such dissolution, and, if necessary, appoint a new general partner of the Partnership.

28

Section 11.2. Merger or Sale of All of the Assets.  A merger or sale of all of the assets of the Partnership must be approved by the Board of Supervisors.

Section 11.3. Liquidation and Termination.  On dissolution of the Partnership, the Board of Supervisors shall act as liquidator or may appoint one or more other Persons as liquidator(s).  The liquidator shall proceed diligently to wind up the affairs of the Partnership and make final distributions as provided herein.  The costs of liquidation shall be borne as a Partnership expense.  Until final distribution, the liquidator shall continue to operate the Partnership properties with all of the power and authority of the Board of Supervisors.  The steps to be accomplished by the liquidator are as follows:

(a)           as promptly as possible after dissolution and again after final liquidation, the liquidator shall cause a proper accounting to be made by a recognized firm of certified public accountants of the Partnership’s assets, liabilities, and operations through the last day of the calendar month in which the dissolution occurs or the final liquidation is completed, as applicable;

(b)           the liquidator shall pay from Partnership funds all of the debts and liabilities of the Partnership (including, without limitation, all expenses incurred in liquidation and any advances described in Section 4.3) or otherwise make adequate provision therefor (including, without limitation, the establishment of a cash escrow fund for contingent liabilities in such amount and for such term as the liquidator may reasonably determine); and

(c)           all remaining assets of the Partnership shall be distributed to the Partners as follows:

(i)            the liquidator may sell any or all Partnership property, including to Partners, and any resulting gain or loss from each sale shall be computed and allocated to the Capital Accounts;

(ii)           with respect to all Partnership property that has not been sold, the fair market value of that property shall be determined and the Capital Accounts shall be adjusted to reflect the manner in which the unrealized income, gain, loss, and deduction inherent in property that has not been reflected in the Capital Accounts previously would be allocated among the Partners if there were a taxable disposition of that property for the fair market value of that property on the date of distribution; and

(iii)          All remaining assets shall be distributed to the Partners in accordance with Section 5.3.  If such distributions do not correspond to the positive capital account balances of the Partners immediately prior to such distributions, then income, gain, loss and deduction for the fiscal year in which the liquidation occurs shall be reallocated among the Partners to cause, to the extent possible, the Partners’ positive capital account balances immediately prior to such distribution to correspond to such amounts, and in the event the income, gain, loss and deduction for the fiscal year in which the liquidation occurs is not sufficient to achieve this result then the income, gain, loss and deduction for prior fiscal years shall be reallocated to achieve such result and the

29

income tax returns of the Partnership which may be amended for this purpose shall be amended and filed as appropriate.

All distributions in kind to the Partners shall be made subject to the liability of each distributee for its allocable share of costs, expenses, and liabilities theretofore incurred or for which the Partnership has committed prior to the date of termination and those costs, expenses, and liabilities shall be allocated to the distributee pursuant to this Section 11.3.  The distribution of cash and/or property to a Partner in accordance with the provisions of this Section 11.3 constitutes a complete return to the Partner of its Capital Contributions and a complete distribution to the Partner of its Partnership Interest and all the Partnership’s property.

Section 11.4. Cancellation of Filing.  On completion of the distribution of Partnership assets as provided herein, the Partnership is terminated, and the Partners (or such other Person or Persons as may be required) shall cause the cancellation of any other filings made as provided in Section 2.6 and shall take such other actions as may be necessary to terminate the Partnership.

ARTICLE XII

GENERAL PROVISIONS

Section 12.1. Offset.  Whenever the Partnership is to pay any sum to any Partner in such Person’s capacity as a Partner, any amounts such Partner owes the Partnership in such Person’s capacity as a Partner may be deducted from that sum before payment.

Section 12.2. Notices.  All notices, requests, or consents provided for or permitted to be given under this Agreement shall be in writing and shall be given either by depositing that writing in the United States mail, addressed to the recipient, postage paid, and certified with return receipt requested, or by depositing that writing with a reputable overnight courier for next day delivery, or by delivering that writing to the recipient in person or by courier or by facsimile transmission.  Unless otherwise provided for herein, a notice, request, or consent given under this Agreement is effective on receipt by the Person to receive it.  All notices, requests, and consents to be sent to a Partner must be sent to or made at the addresses given for that Partner on Schedule A, in the relevant Adoption Agreement or Adoption Agreement for Family Members or such other address as that Partner may specify by notice to the other Partners.  Any notice, request, or consent to the Partnership shall be given to the Board of Supervisors at its address on Schedule A and to the following address:

Athlon Holdings LP
Attn: Robert C. Reeves
420 Throckmorton St, Ste 1200
Fort Worth, TX 76102

Section 12.3. Entire Agreement; Supersedure.  Except as otherwise stated herein, this Agreement constitutes the entire agreement of the Partners relating to the Partnership and supersedes all prior contracts or agreements with respect to the Partnership, whether oral or written.

30

Section 12.4. Effect of Waiver or Consent.  A waiver or consent, express or implied, to or of any breach or default by any Person in the performance by that Person of its obligations with respect to the Partnership is not a consent or waiver to or of any other breach or default in the performance by that Person of the same or any other obligations of that Person with respect to the Partnership.  Failure on the part of a Person to complain of any act of any Person or to declare any Person in default with respect to the Partnership, irrespective of how long that failure continues, does not constitute a waiver by that Person of its rights with respect to that default until the applicable limitations period has expired.

Section 12.5. Amendment or Modification.

(a)           This Agreement may be amended, modified, waived or supplemented by the Board of Supervisors; provided, that except as expressly provided in this Agreement, no amendment, modification, waiver or supplement of this Agreement shall, without the consent of the affected Partner, (i) alter the provisions which govern such Partner’s entitlement to distributions and income allocations or (ii) decrease the interest in the Partnership of such Partner (including the provisions providing for allocation of debits and credits to such Partner’s Capital Account provided for in this Agreement).

(b)           Notwithstanding the first proviso in Section 12.5(a), no consent of any Limited Partner will be required for the Board of Supervisors to make an amendment (i) necessitated by a merger agreement or similar document provided that all consideration from such transaction is allocated among the Partners as provided in this Agreement and any Partnership Interests issued in such transaction are issued in accordance with the terms of this Agreement, (ii) necessary or advisable to reflect, account for and deal with appropriately the formation by the Partnership of, or investment by the Partnership in, any corporation, partnership, joint venture, limited liability company or other entity, (iii) necessary or advisable to effect or continue the irrevocable delegation by the General Partner to the Board of Supervisors of all management powers over the business and affairs of the Partnership, (iv) necessary or advisable to prevent the Partnership, any Partner or any member of the Board of Supervisors from being subjected to the Investment Company Act of 1940 or the Investment Advisers Act of 1940, as amended, (iv) necessary or advisable to satisfy any requirements, conditions or guidelines contained in any opinion, directive, order, ruling or regulation of any federal or state agency or judicial authority or contained in any federal or state statute, or (v) necessary or advisable to qualify or continue the qualification of the Partnership as a limited partnership or a partnership in which the Limited Partners have limited liability under the laws of any state or to ensure that the Partnership will not be treated as an association taxable as a corporation or otherwise taxed as an entity for federal income tax purposes.

(c)           Notwithstanding either proviso in Section 12.5(a), no consent of any Limited Partner will be required for the Board of Supervisors to make an amendment in connection with (i) the admission, substitution, withdrawal or removal of Partners in accordance with this Agreement or (ii) the issuance, repurchase, forfeiture or re-issuance of any class or series of securities of the Partnership in accordance with this Agreement.

Section 12.6. Binding Effect.  Subject to the restrictions on Dispositions set forth in this Agreement, this Agreement is binding on and inures to the benefit of the Partners.  This

31

Agreement is for the sole benefit of the Partners, and no other Person shall have any rights, benefits or remedies by reason of this Agreement, nor shall any Partner owe any duty or obligation whatsoever to any such Person (other than the Partners) by virtue of this Agreement.

Section 12.7. Governing Law; Jurisdiction; Waiver of Jury Trial.

(a)           This Agreement shall be governed by and construed in accordance with the applicable laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflict of law hereof.

(b)           The parties hereto, on their behalf and on behalf of their respective Affiliates, irrevocably submit to the exclusive jurisdiction of the Court of Chancery of the State of Delaware (or, if such Court or the Delaware Supreme Court determines that the Court of Chancery does not have or should not exercise subject matter jurisdiction over such matter, the Superior Court of the State of Delaware) and the federal courts of the United States of America located in the State of Delaware (and of the appropriate appellate courts therefrom) in connection with any dispute arising out of, in connection with, in respect of, or in any way relating to:

(i)            the negotiation, execution and performance of this Agreement,

(ii)           the interpretation and enforcement of the provisions of this Agreement, or

(iii)          any actions of or omissions by any Covered Party in any way connected with, related to or giving rise to any of the foregoing matters,

(the foregoing clauses (i), (ii) and (iii) collectively, the “Covered Matters”), and hereby waive, and agree not to assert as a defense in any actions, suits or proceedings (each, a “Legal Action”) with regard to or involving a Covered Matter, that such Legal Action may not be brought or is not maintainable in said courts or that venue thereof may not be appropriate or that this Agreement or any such document may not be enforced in or by such courts, and the parties hereto, on their behalf and on behalf of their respective Affiliates, irrevocably agree that all claims with respect to such Legal Action shall be heard and determined exclusively by such a Delaware state or federal court.  The parties hereto, on their behalf and on behalf of their respective Affiliates, hereby consent to and grant any such court jurisdiction over the Person of such parties and over the subject matter of such dispute and agree that mailing of process or other papers in connection with such Legal Action in the manner provided in Section 12.2 or in such other manner as may be permitted by law shall be valid and sufficient service thereof.

(c)           In addition, by entering into this Agreement, each party hereto, on their behalf and, to the fullest extent permissible by applicable law, on behalf of their respective unitholders, partners, members, directors, Affiliates, officers or agents, as the case may be, covenants, agrees and acknowledges, that it shall not bring any Legal Action (regardless of the legal theory or claim involved or the procedural nature of any such Legal Action) with regard to any Covered Matter against any Covered Party, other than the parties hereto.

(d)           The parties hereto acknowledge and agree that (i) the agreements contained in this Section 12.7 are an integral part of this Agreement and the transactions

32

contemplated hereby, and that, without these agreements, the parties would not enter into this Agreement, (ii) any breach of this Section 12.7 would result in irreparable harm and that monetary damages would not a sufficient remedy for any such breach and (iii) that any breach of this Section 12.7 will be deemed a material breach of this Agreement.  Accordingly, each Covered Party shall be entitled to equitable relief, including injunction and specific performance, as a remedy for any such breach by a party (or any affiliate of such party) and in case of any such breach, the non-breaching party shall be excused from its performance obligations under this Agreement. For the purposes of this Section 12.7, “Covered Party” shall mean (i) any party hereto, and (ii) any such parties’ officers, directors, agents, employees, or Affiliates, all of whom are intended third party beneficiaries of this Section 12.7.

(e)           EACH OF THE PARTIES HERETO IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING BETWEEN THE PARTIES HERETO ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

Section 12.8. Severability.  If any provision of this Agreement or its application to any Person or circumstance is held invalid or unenforceable to any extent, the remainder of this Agreement and the application of such provision to other Persons or circumstances is not affected and such provision shall be enforced to the greatest extent permitted by law.

Section 12.9. Further Assurances.  In connection with this Agreement and the transactions contemplated hereby, each Partner shall execute and deliver any additional documents and instruments and perform any additional acts that may be necessary or appropriate to effectuate and perform the provisions of this Agreement and such transactions.

Section 12.10. Counterparts.  This Agreement may be executed in any number of counterparts with the same effect as if all signatories had signed the same document.  All counterparts shall be construed together and constitute the same instrument.

[Signature Pages Follow]

33

Executed effective as of the date first set forth above.

GENERAL PARTNER:
ATHLON HOLDINGS GP LLC
By:
	Name:	Robert C. Reeves
	Title:	Manager
LIMITED PARTNERS:
ATHLON ENERGY INC.
By:
	Name:
	Title:

LIMITED PARTNERS (CONT’D):
By:
	Robert C. Reeves
By:
	Nelson K. Treadway
By:
	William B. D. Butler
By:
	Jennifer L. Palko
By:
	Bud W. Holmes
By:
	David B. McClelland
By:
	James R. Plemons
By:
	Melvyn E. Foster, Jr.
By:
	Matt Cashion
By:
	Janis F. Gould
By:
	Juan Coronado
By:
	Sharon Braddy

By:
	John Souders
By:
	Sheryl Turner
By:
	Lauryl Ellis
By:
	Robert Lange
By:
	Dallas Rysavy
By:
	Dustin Cummings
By:
	J.W. Reddin
By:
	Margie Pellerin
By:
	Ian Bowersock
By:
	Joey Bernard
By:
	Cristan C. Erdelac

EX-21.1

Exhibit 21.1

Subsidiaries of Athlon Energy Inc. as of July 12, 2013

Name of Subsidiary	State or other Jurisdiction of Incorporation or Organization
Athlon Holdings LP	Delaware
Athlon Energy LLC	Delaware
Athlon Energy LP	Delaware
Athlon FE Energy LP	Delaware
Athlon Energy Operating LLC	Delaware
Athlon FE Operating LLC	Delaware
Athlon Finance Corp.	Delaware

EX-23.1

QuickLinks -- Click here to rapidly navigate through this document

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption "Experts" and to the use of our report dated March 8, 2013 with respect to the consolidated financial statements of Athlon Holdings LP and our report dated June 4, 2013 with respect to the balance sheet of Athlon Energy Inc., in Amendment No. 2 to the Registration Statement (Form S-1 No. 333-189109) and related Prospectus of Athlon Energy Inc. dated July 12, 2013.

/s/ ERNST & YOUNG LLP

Fort Worth, Texas
July 12, 2013

QuickLinks

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

EX-23.2

QuickLinks -- Click here to rapidly navigate through this document

Exhibit 23.2

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption "Experts" and to the use of our report dated May 16, 2012 with respect to the carve out financial statements of Element Petroleum, LP's Permian Basin Operations as of and for the nine months ended September 30, 2011 in Amendment No. 2 to the Registration Statement (Form S-1 No. 333-189109) and related Prospectus of Athlon Energy Inc. dated July 12, 2013.

        /s/ UHY LLP

Houston, Texas
July 12, 2013

QuickLinks

Exhibit 23.2

Consent of Independent Registered Public Accounting Firm

EX-23.3

QuickLinks -- Click here to rapidly navigate through this document

Exhibit 23.3

CAWLEY, GILLESPIE & ASSOCIATES, INC.

	PETROLEUM CONSULTANTS
13640 BRIARWICK DRIVE, SUITE 100 AUSTIN, TEXAS 78729-1707 512-249-7000	306 WEST SEVENTH STREET, SUITE 302 FORT WORTH, TEXAS 76102-4987 817- 336-2461 www.cgaus.com	1000 LOUISIANA STREET, SUITE 625 HOUSTON, TEXAS 77002-5008 713-651-9944

CONSENT OF INDEPENDENT PETROLEUM ENGINEERS

        We hereby consent to the references to our firm in this Amendment No. 2 to the Registration Statement on Form S-1 and all appendixes, exhibits and attachments thereto (including the related prospectus) filed by Athlon Energy Inc., and to the use of our audit of their reserves and reserves present value as of December 31, 2011 and 2012 for Athlon Energy Inc. and its predecessors (the "Registration Statement"). We also consent to all references to our firm in the prospectus included in such Registration Statement, including under the heading "Experts."

Sincerely,

/s/ Robert Ravnaas
Cawley, Gillespie & Associates, Inc.

Texas Registered Engineering Firm F-693

July 12, 2013
Fort Worth, Texas

QuickLinks

Exhibit 23.3

CAWLEY, GILLESPIE & ASSOCIATES, INC.
CONSENT OF INDEPENDENT PETROLEUM ENGINEERS