8-K/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K/A

(Amendment No. 1)

CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): March 27, 2012 (January 13, 2012)

WESTERN GAS PARTNERS, LP

(Exact name of registrant as specified in its charter)

Delaware	001-34046	26-1075808
(State or other jurisdiction of incorporation or organization)	(Commission File Number)	(I.R.S. Employer Identification No.)

1201 Lake Robbins Drive

The Woodlands, Texas 77380-1046

(Address of principal executive offices) (Zip Code)

(832) 636-6000

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

¨     Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨     Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨     Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨     Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

EXPLANATORY NOTE

On January 17, 2012, Western Gas Partners, LP (the “Partnership”) filed a Current Report on Form 8-K (the “Initial Report”) to report, among other things, the closing of its acquisition of certain midstream assets from affiliates of Anadarko Petroleum Corporation (“Anadarko”), consisting of a 100% ownership interest in Mountain Gas Resources, LLC (or “MGR”), which owns (i) the Red Desert Complex, located in the greater Green River Basin in southwestern Wyoming, including the Patrick Draw processing plant with a capacity of 125 MMcf/d, the Red Desert processing plant with a capacity of 48 MMcf/d, 1,295 miles of gathering lines, and related facilities; (ii) a 22% interest in Rendezvous Gas Services, LLC (“Rendezvous”), which owns a 338-mile mainline gathering system serving the Jonah and Pinedale Anticline fields in southwestern Wyoming; and (iii) certain additional midstream assets and equipment. These assets are collectively referred to as the “MGR assets” and the acquisition as the “MGR acquisition.” The consideration paid by the Partnership for the MGR acquisition consisted of (i) $458.6 million in cash, (ii) 632,783 common units of the Partnership and (iii) 12,914 general partner units of the Partnership issued to the Partnership’s general partner, Western Gas Holdings, LLC (the “general partner” or “GP”). The Partnership funded the cash consideration through (i) $299.0 million in borrowings under its revolving credit facility and (ii) $159.6 million of cash on hand. The terms of the MGR acquisition were approved by the Board of Directors of the GP and by the Board’s special committee on December 15, 2011. The MGR acquisition closed on January 13, 2012, with an effective date of January 1, 2012.

This Current Report on Form 8-K/A (the “Amendment”) amends and supplements the Initial Report to include the financial statements of the MGR assets and the unaudited pro forma financial statements of the Partnership required by Items 9.01(a) and 9.01(b) of Form 8-K and to include exhibits under Item 9.01(d) of Form 8-K. No other modifications to the Initial Report are being made by this Amendment.

Item 9.01 Financial Statements and Exhibits.

(a) Financial Statements of Businesses Acquired

Financial Statements of the MGR assets as of and for the year ended December 31, 2011, a copy of which is included as Exhibit 99.1 to this Current Report on Form 8-K/A, incorporated herein by reference.

(b) Pro Forma Financial Information

Unaudited Pro Forma Condensed Consolidated Financial Statements of the Partnership as of and for the year ended December 31, 2011, a copy of which is included as Exhibit 99.2 to this Current Report on Form 8-K/A, incorporated herein by reference.

(d) Exhibits

23.1 Consent of KPMG LLP.

99.1 Financial Statements of the MGR assets as of and for the year ended December 31, 2011.

99.2 Unaudited Pro Forma Condensed Consolidated Financial Statements of the Partnership as of and for the year ended December 31, 2011.

2

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	WESTERN GAS PARTNERS, LP
	By:	Western Gas Holdings, LLC, its general partner
Date: March 27, 2012	By:	/s/ Donald R. Sinclair
		Donald R. Sinclair
		President and Chief Executive Officer

3

EXHIBIT INDEX

Exhibit Number	Exhibit Title
23.1	Consent of KPMG LLP.
99.1	Financial Statements of the MGR assets as of and for the year ended December 31, 2011.
99.2	Unaudited Pro Forma Condensed Consolidated Financial Statements of the Partnership as of and for the year ended December 31, 2011.

4

EX-23.1

EXHIBIT 23.1

Consent of Independent Registered Public Accounting Firm

The Board of Directors

Western Gas Holdings, LLC (as general partner of Western Gas Partners, LP):

We consent to the incorporation by reference in the registration statements on Form S-3 (No. 333-174043) and Form S-8 (No. 333-151317), of Western Gas Partners, LP of our report dated March 27, 2012, with respect to the balance sheet of Western Gas Partners, LP’s MGR Assets as of December 31, 2011, and the related statements of income, parent net equity, and cash flows for the year then ended, which report appears in the Current Report on Form 8-K/A of Western Gas Partners, LP dated March 27, 2012.

/s/ KPMG LLP

Houston, Texas

March 27, 2012

EX-99.1

EXHIBIT 99.1

MGR ASSETS

INDEX TO FINANCIAL STATEMENTS

Report of Independent Registered Public Accounting Firm	2
Statement of Income for the year ended December 31, 2011	3
Balance Sheet as of December 31, 2011	4
Statement of Parent Net Equity for the year ended December 31, 2011	5
Statement of Cash Flows for the year ended December 31, 2011	6
Notes to Financial Statements	7

Report of Independent Registered Public Accounting Firm

The Board of Directors and Unitholders

Western Gas Holdings, LLC (as general partner of Western Gas Partners, LP):

We have audited the accompanying balance sheet of Western Gas Partners, LP’s MGR Assets as of December 31, 2011, and the related statements of income, parent net equity, and cash flows for the year then ended. These financial statements are the responsibility of Western Gas Partners, LP’s (the Partnership) management. Our responsibility is to express an opinion on these financial statements based on our audit.

We conducted our audit in accordance with generally accepted auditing standards as established by the Auditing Standards Board (United States) and in accordance with the auditing 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. The Partnership is not required to have, nor were we engaged to perform, an audit of its 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 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, as well as 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 financial position of Western Gas Partners, LP’s MGR Assets as of December 31, 2011, and the results of its operations and its cash flows for the year then ended in conformity with U.S. generally accepted accounting principles.

/s/ KPMG LLP

Houston, Texas

March 27, 2012

2

MGR ASSETS

STATEMENT OF INCOME

thousands	Year Ended   December 31, 2011
Revenues – affiliates
Gathering, processing and transportation of natural gas and natural gas liquids		$      1,783
Natural gas, natural gas liquids and condensate sales		140,801
Equity income		1,171
Total revenues – affiliates		143,755
Revenues – third parties
Gathering, processing and transportation of natural gas and natural gas liquids		12,954
Other, net		2,851
Total revenues – third parties		15,805
Total revenues		159,560
Operating expenses
Cost of product (1)		80,443
Operation and maintenance (1)		17,351
General and administrative (1)		3,725
Property and other taxes		885
Depreciation, amortization and impairments		23,450
Total operating expenses		125,854
Operating income		33,706
Interest income, net on affiliate balances		12,874
Other income (expense), net		1,580
Income before income taxes		48,160
Income tax expense		16,857
Net income		$    31,303

⁽¹⁾  Operating expenses include charges from affiliates (as defined in Note 1) to the Partnership’s MGR assets (as defined in Note 1), for services and amounts paid by affiliates to third parties on behalf of the Partnership’s MGR assets. For the year ended December 31, 2011, cost of product includes product purchases from affiliates of $8.2 million, operation and maintenance includes charges from affiliates of $7.2 million, and general and administrative includes charges from affiliates of $3.7 million. See Note 3.

See accompanying Notes to Financial Statements.

3

MGR ASSETS

BALANCE SHEET

thousands	December 31, 2011
ASSETS
Current assets
Accounts receivable		$         506
Other current assets		392
Total current assets		898
Plant, property and equipment
Cost		414,213
Less accumulated depreciation		132,923
Net property, plant and equipment		281,290
Goodwill		18,000
Equity investments		69,839
Other assets		15,979
Total assets		$ 386,006
LIABILITIES AND PARENT NET EQUITY
Current liabilities
Accounts payable		$        856
Accrued ad valorem taxes		304
Accrued liabilities		4,342
Total current liabilities		5,502
Deferred income taxes		106,504
Asset retirement obligations and other		4,400
Total long-term liabilities		110,904
Total liabilities		116,406
Parent net equity		269,600
Total liabilities and parent net equity		$ 386,006

See accompanying Notes to Financial Statements.

4

MGR ASSETS

STATEMENT OF PARENT NET EQUITY

thousands
Balance at December 31, 2010	$ 287,603
Net income	31,303
Net distributions to Parent	(49,306)
Balance at December 31, 2011	$ 269,600

See accompanying Notes to Financial Statements.

5

MGR ASSETS

STATEMENT OF CASH FLOWS

thousands	Year Ended   December 31, 2011
Cash flows from operating activities
Net income		$   31,303
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and impairments		23,450
Deferred income taxes		(2,747)
Changes in assets and liabilities:
Decrease in accounts receivable, net		210
Decrease in accounts payable and accrued liabilities, net		(249)
Change in other items, net		4,790
Net cash provided by operating activities		56,757
Cash flows from investing activities
Capital expenditures		(7,451)
Net cash used in investing activities		(7,451)
Cash flows from financing activities
Net distributions to Parent		(49,306)
Net cash used in financing activities		(49,306)
Net increase (decrease) in cash and cash equivalents		—
Cash and cash equivalents at beginning of period		—
Cash and cash equivalents at end of period		$          —
Supplemental disclosures
Decrease in accrued capital expenditures		$        105

See accompanying Notes to Financial Statements.

6

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

1.  DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION

The accompanying financial statements and related notes present the financial position, results of operations, cash flows and parent net equity of certain midstream assets acquired by Western Gas Partners, LP (the “Partnership”) from certain affiliates of Anadarko Petroleum Corporation. Specifically, the acquired assets consist of a 100% ownership interest in Mountain Gas Resources, LLC (or “MGR LLC”), which owns (i) the Red Desert Complex, located in the greater Green River Basin in southwestern Wyoming, including the Patrick Draw processing plant with a capacity of 125 MMcf/d, the Red Desert processing plant with a capacity of 48 MMcf/d, 1,295 miles of gathering lines, and related facilities, (ii) a 22% interest in Rendezvous Gas Services, LLC (“Rendezvous”), which owns a 338-mile mainline gathering system serving the Jonah and Pinedale Anticline fields in southwestern Wyoming, and (iii) certain additional midstream assets and equipment. These assets are collectively referred to as the “MGR assets” or “MGR” and the acquisition as the “MGR acquisition.”

MGR provides a combination of gathering, compression, treating and processing services. Anadarko Petroleum Corporation acquired the MGR assets in connection with its August 23, 2006, acquisition of Western Gas Resources, Inc. For purposes of these financial statements, the “Partnership” refers to Western Gas Partners, LP and its consolidated subsidiaries. The Partnership’s general partner is Western Gas Holdings, LLC (the “general partner” or “GP”), a wholly owned subsidiary of Anadarko Petroleum Corporation. “Anadarko” or “Parent” refers to Anadarko Petroleum Corporation and its consolidated subsidiaries, excluding the Partnership; and “affiliates” refers to wholly owned and partially owned subsidiaries of Anadarko, excluding the Partnership.

These financial statements were prepared in connection with the Partnership’s acquisition of the MGR assets from Anadarko and incorporate the activities and account balances of MGR as reflected in the historical cost-basis accounts of the Parent with certain adjustments made in order to reasonably reflect substantially all of the costs of doing business. These adjustments required the use of management’s assumptions, allocations and estimates.

These accompanying financial statements and notes thereto were prepared for the purpose of complying with the U.S. Securities and Exchange Commission rules and regulations, including but not limited to Regulation S-X, Article 3, General Instructions as to Financial Statements, and Staff Accounting Bulletin Topic 1-B, Allocation of Expenses and Related Disclosure in Financial Statements of Subsidiaries, Divisions or Lesser Business Components of Another Entity. Certain expenses incurred by the Parent were only indirectly attributable to MGR. In connection with the MGR acquisition effective January 1, 2012, agreements between Anadarko and the Partnership also became effective for MGR. These agreements materially affected certain items related to the MGR assets, primarily general and administrative expense and settlements of affiliate-based transactions. On January 1, 2012, the MGR assets will be consolidated by the Partnership, which generally is not subject to federal or state income tax, other than Texas margin tax, thereby eliminating the applicability of entity-level federal income taxation for income attributable to the MGR assets. Accordingly, these financial statements are not indicative of the actual results of operations that would have occurred if the MGR assets had been operated separately during the periods reported and are also not indicative of future results of operations. Transactions between the MGR assets and the Parent have been identified in the financial statements as transactions between affiliates. The allocations and related estimates and assumptions are more fully described in Note 2 and Note 3.

The information furnished herein reflects all normal recurring adjustments that are, in the opinion of management, necessary for a fair statement of financial position as of December 31, 2011, and for the results of operations, changes in Parent net equity and cash flows for the year ended December 31, 2011.

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Use of estimates. In preparing financial statements in accordance with generally accepted accounting principles in the United States, management makes informed judgments and estimates that affect the amounts reported in the financial statements and the notes thereto. Management evaluates its estimates and related assumptions regularly, utilizing historical experience and other methods considered reasonable under the circumstances. Changes in facts and circumstances or additional information may result in revised estimates, and actual results may differ from these estimates. Effects on MGR’s business, financial position and results of operations resulting from revisions to estimates are recognized when the facts that give rise to each revision become known.

7

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Fair value. The fair-value-measurement standard defines fair value 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. The standard characterizes inputs used in determining fair value according to a hierarchy that prioritizes those inputs based upon the degree to which they are observable. The three levels of the fair value hierarchy are as follows:

Level 1 – Inputs represent quoted prices in active markets for identical assets or liabilities.

Level 2 – Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (for example, quoted market prices for similar assets or liabilities in active markets or quoted market prices for identical assets or liabilities in markets not considered to be active, inputs other than quoted prices that are observable for the asset or liability, or market-corroborated inputs).

Level 3 – Inputs that are not observable from objective sources, such as management’s internally developed assumptions used in pricing an asset or liability (for example, an estimate of future cash flows used in management’s internally developed present value of future cash flows model that underlies the fair value measurement).

Nonfinancial assets and liabilities initially measured at fair value include long-lived assets (asset groups), goodwill, initial recognition of asset retirement obligations and initial recognition of environmental obligations assumed in a third-party acquisition. Impairment analyses for long-lived assets, goodwill, and the initial recognition of asset retirement obligations and environmental obligations use Level 3 inputs. When MGR is required to measure fair value, and there is not a market-observable price for the asset or liability or a market-observable price for a similar asset or liability, MGR utilizes the cost, income, or market valuation approach depending on the quality of information available to support management’s assumptions.

The carrying amounts of accounts receivable and accounts payable reported on the accompanying balance sheet approximate fair value due to the short-term nature of these items.

Bad-debt reserve. A majority of the revenues earned by the MGR assets are from Anadarko, for which no credit limit is maintained. MGR’s management analyzes its exposure to bad debts on a customer-by-customer basis for third-party accounts receivable and may establish credit limits for significant third-party customers. There were no amounts recorded for bad-debt reserves for the MGR assets at December 31, 2011.

Property, plant and equipment. Property, plant and equipment are generally stated at the lower of historical cost less accumulated depreciation or at fair value, if impaired. All construction-related direct labor and material costs are capitalized. The cost of renewals and betterments that extend the useful life of property, plant and equipment is also capitalized. The cost of repairs, replacements and major maintenance projects that do not extend the useful life or increase the expected output of property, plant and equipment is expensed as incurred.

Depreciation is computed over the asset’s estimated useful life using the straight-line method based on estimated useful lives and salvage values of assets. Uncertainties that may impact these estimates include, but are not limited to, changes in laws and regulations relating to environmental matters, including air and water quality, restoration and abandonment requirements, economic conditions and supply and demand in the area. When assets are placed into service, management makes estimates with respect to useful lives and salvage values that management believes are reasonable. However, subsequent events could cause a change in estimates, thereby impacting future depreciation amounts.

Management of MGR evaluates the ability to recover the carrying amount of its long-lived assets to determine whether its long-lived assets have been impaired. Impairments exist when the carrying amount of an asset exceeds estimates of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. When alternative courses of action to recover the carrying amount of a long-lived asset are under consideration, estimates of future undiscounted cash flows take into account possible outcomes and probabilities of their occurrence. If the carrying amount of the long-lived asset is not recoverable based on the estimated future undiscounted cash flows, the impairment loss is measured as the excess of the asset’s carrying amount over its estimated fair value, such that the asset’s carrying amount is adjusted to its estimated fair value with an offsetting charge to impairment expense.

8

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

During the year ended December 31, 2011, an impairment of $7.3 million was recognized for certain MGR equipment and materials. The costs of these equipment and materials, previously capitalized as assets under construction and related to a Red Desert complex expansion project, were deemed no longer recoverable as the expansion project was indefinitely postponed by Anadarko management. Subsequent to the project evaluation and impairment, the remaining fair value of the equipment and materials, approximately $10.6 million, was reclassified from within property, plant and equipment to other assets on the accompanying balance sheet. Also during 2011, following an evaluation of future cash flows, an impairment of $3.0 million was recognized for a transportation pipeline. This asset was impaired to fair value, estimated using Level 3 fair-value inputs.

Goodwill. Goodwill included in the accompanying financial statements represents the portion of Anadarko’s gathering and processing reporting unit goodwill attributed to the MGR assets and acquired by the Partnership. The carrying value of Anadarko’s gathering and processing reporting unit goodwill represents the excess of the purchase price of an entity over the estimated fair value of the identifiable assets acquired and liabilities assumed by Anadarko. Accordingly, the goodwill balance does not reflect, and in some cases is significantly different than, the difference between the consideration paid and the fair value of the net assets on the acquisition date. The accompanying balance sheet as of December 31, 2011, includes goodwill of $18.0 million, none of which is deductible for tax purposes.

Management of MGR evaluates goodwill for impairment annually, as of October 1, or more often as facts and circumstances warrant. The first step in the goodwill impairment test is to compare the fair value of each reporting unit to which goodwill has been assigned to the carrying amount of net assets, including goodwill, of the respective reporting unit. If the carrying amount of the reporting unit exceeds its fair value, step two in the goodwill impairment test requires goodwill to be written down to its implied fair value through a charge to operating expense based on a hypothetical purchase price allocation. The MGR assets’ goodwill is a portion of the goodwill attributed to one reporting unit. No goodwill impairment has been recognized in these financial statements. The carrying value of goodwill after such an impairment would represent a Level 3 fair value measurement.

Equity-method investments. The MGR assets include a 22% interest in Rendezvous, which is a limited liability company that operates gas-gathering facilities in western Wyoming and is accounted for under the equity method. The investment balance at December 31, 2011, was $69.8 million. For the year ended December 31, 2011, investment earnings, net of amortization, was $1.2 million and distributions were $5.4 million. Certain business decisions, including, but not limited to, decisions with respect to significant expenditures or contractual commitments, annual budgets, material financings, dispositions of assets or amending the members’ gas servicing agreements, require unanimous approval of the members.

The investment balance at December 31, 2011, includes $47.9 million for the purchase price allocated to the investment in Rendezvous in excess of the historic cost basis originally recorded by Western Gas Resources, Inc. (“WGR”) (the entity that owned the interest in Rendezvous, which Anadarko acquired in August 2006). This excess balance is attributable to the difference between the fair value and book value of Rendezvous’ gathering and treating facilities at the time WGR was acquired by Anadarko, and is being amortized over the remaining estimated useful life of those facilities.

Other assets. As of December 31, 2011, other assets include a $0.7 million receivable recognized in conjunction with the capital lease component of a processing agreement, which extends through November 2014 in which MGR is the lessor, and $4.6 million of unguaranteed residual value related to this processing plant, based on a measurement of fair value estimated when the plant was acquired by Anadarko in 2006. Interest income is recorded to other income (expense), net on the accompanying statement of income.

9

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Asset retirement obligations. MGR recognizes a liability based on the estimated costs of retiring tangible long-lived assets. The liability is recognized at fair value, measured using discounted expected future cash outflows for the asset retirement obligation when the obligation originates, which generally is when an asset is acquired or constructed. The carrying amount of the associated asset is increased commensurate with the liability recognized. Over time, the discounted liability is accreted through accretion expense to its expected settlement value. Subsequent to the initial recognition, the liability is also adjusted for any changes in the expected value of the retirement obligation (with a corresponding adjustment to property, plant and equipment) until the obligation is settled. Revisions in estimated asset retirement obligations may result from changes in estimated inflation rates, discount rates, asset retirement costs and the estimated timing of settling asset retirement obligations. See Note 6.

Environmental expenditures. Environmental expenditures related to conditions caused by past operations that do not generate current or future revenues are expensed. Environmental expenditures related to operations that generate current or future revenues are expensed or capitalized, as appropriate. Liabilities are recorded when the necessity for environmental remediation or other potential environmental liabilities becomes probable and the costs can be reasonably estimated. Accruals for estimated losses from environmental remediation obligations are recognized no later than at the time of the completion of the remediation feasibility study. These accruals are adjusted as additional information becomes available or as circumstances change. Costs of future expenditures for environmental-remediation obligations are not discounted to their present value. See Note 7.

Revenues and cost of product. Under its fee-based gathering, treating and processing arrangements, the MGR assets earn a fixed fee based on the volume and thermal content of natural gas and revenues are recognized for services in the month such services are performed. Producers’ wells are connected to the MGR assets’ gathering systems for delivery of natural gas to processing plants, where the natural gas is processed to extract NGLs and condensate. In some areas where no processing is required, the producers’ gas is gathered and delivered to pipelines for market delivery. Under percent-of-proceeds contracts, revenue is recognized when the natural gas, NGLs or condensate are sold and the related purchases are recorded as a percentage of the product sale.

MGR purchases natural gas volumes at the wellhead for gathering and processing. As a result, the MGR assets have volumes of NGLs and condensate to sell and volumes of residue gas to either sell, to use for system fuel or to satisfy keep-whole obligations. In addition, depending upon specific contract terms, condensate and NGLs recovered during gathering and processing are either returned to the producer or retained and sold. Under keep-whole contracts, when condensate or NGLs are retained and sold, producers are kept whole for the condensate or NGL volumes through the receipt of a thermally equivalent volume of residue gas or the value thereof. The keep-whole contract conveys an economic benefit when the combined value of the individual NGLs is greater in the form of liquids than as a component of the natural gas stream; however, the MGR assets are adversely impacted when the value of the NGLs is lower as liquids than as a component of the natural gas stream. Revenue is recognized from the sale of condensate and NGLs upon transfer of title and related purchases are recorded as cost of product.

Transportation revenues are generated from interruptible contracts pursuant to which a fee is charged to the customer based on volumes transported through the pipeline. Revenues for transportation of natural gas in the form of usage fees and interruptible contracts are recognized when the volumes are received into the pipeline.

Proceeds from the sale of residue gas, NGLs and condensate are reported as revenues from natural gas, natural gas liquids and condensate sales in the accompanying statement of income. Revenues attributable to the fixed-fee component of gathering and processing contracts as well as usage fees on transportation contracts are reported as revenues from gathering, processing and transportation of natural gas and natural gas liquids in the accompanying statement of income.

In connection with the MGR acquisition, the Partnership entered into 10-year, fee-based gathering and processing agreements with Anadarko effective December 1, 2011, for all affiliate throughput on the MGR assets. See Note 8.

Cash. The Parent provided cash as needed to support the MGR assets and collected cash from the services provided by the MGR assets. Consequently, the accompanying balance sheet does not include any cash balances. See Note 3 for information on the Parent’s centralized cash management process. Net cash paid to or received from the Parent is reflected as net contributions from or distributions to the Parent on the accompanying statements of parent net equity and cash flows.

10

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Income taxes. The MGR assets are not subject to income tax as a stand-alone entity. The current federal and state income taxes included in these financial statements represent the MGR assets’ allocable share of Anadarko’s current federal and state income taxes. Deferred federal and state income taxes are provided on temporary differences between the financial statement carrying amounts of recognized assets and liabilities and their respective tax bases as if tax returns were filed for the MGR assets as a stand-alone entity.

Subsequent events. MGR has evaluated subsequent events through March 27, 2012, the date the financial statements were available to be issued.

Recently issued accounting standard not yet adopted. In September 2011, the Financial Accounting Standards Board issued an Accounting Standards Update (“ASU”) that permits an initial assessment of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount for goodwill impairment testing purposes. Thus, determining a reporting unit’s fair value is not required unless, as a result of the qualitative assessment, it is more likely than not that the fair value of the reporting unit is less than its carrying amount. This ASU is effective prospectively beginning January 1, 2012. Adoption of this ASU will have no impact on the financial statements.

3.  TRANSACTIONS WITH AFFILIATES

Affiliate transactions. Revenues from affiliates include amounts earned by the MGR assets from services provided to Anadarko and the Partnership, as well as from the sale of residue gas, condensate and NGLs to Anadarko and the Partnership. In addition, MGR purchases natural gas from an affiliate of Anadarko and the Partnership pursuant to gas purchase agreements. Operating and maintenance expense includes amounts accrued for or paid to affiliates for the operation of the MGR assets, whether in providing services to affiliates or to third parties, including field labor, measurement and analysis, and other disbursements. Affiliate expenses do not inherently bear a direct relationship to affiliate revenues, and third-party expenses do not necessarily bear a direct relationship to third-party revenues.

Cash management. Anadarko operates a cash management system whereby excess cash from most of its subsidiaries, held in separate bank accounts, is swept into a centralized account. Sales and purchases related to MGR’s third-party transactions were received or paid in cash by Anadarko within the centralized cash management system and were ultimately settled through an adjustment to parent net equity. Prior to December 7, 2011, Anadarko charged, or credited, MGR interest at a variable rate on outstanding affiliate balances for the periods these balances remained outstanding. Beginning December 7, 2011, in connection with a determination by the sole member of MGR to eliminate intercompany balances without cash settlement, Anadarko discontinued charging interest on intercompany balances. The outstanding affiliate balances were entirely settled through an adjustment to parent net equity in connection with the MGR acquisition.

Allocation of costs. MGR does not have any employees. The employees supporting the operations of the MGR assets are employees of Anadarko. For the purpose of these financial statements, a portion of Anadarko’s general and administrative expenses have been allocated to MGR in the form of a management services fee and included in the accompanying statement of income. The management services fee represents allocable costs, including compensation, benefits, pension and postretirement costs, associated with the provision of services for or on the behalf of MGR by the Parent related to the following: (i) various business services, including but not limited to, payroll, accounts payable and facilities management; and (ii) various corporate services, including, but not limited to, legal, accounting, treasury, information technology and human resources. General, administrative and management costs were allocated to MGR based on its proportionate share of the Parent’s assets and revenues. Management considers these allocation methodologies to be reasonable.

11

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

3.  TRANSACTIONS WITH AFFILIATES (CONTINUED)

Summary of affiliate transactions. Affiliate transactions include revenue from affiliates, operating expenses accrued or paid, and purchases of natural gas. The following table summarizes affiliate transactions, including transactions with Anadarko, its affiliates and the Partnership:

thousands	Year Ended   December 31, 2011
Revenues		$  143,755
Cost of product		8,167
Operation and maintenance		7,191
General and administrative		3,725
Operating expenses		19,083
Interest income, net on affiliate balances		12,874

Concentration of credit risk. Anadarko was the only customer from whom revenues exceeded 10% of the MGR assets’ revenues for the year ended December 31, 2011.

4.  INCOME TAXES

Components of income tax expense for the MGR assets are as follows:

thousands	Year Ended   December 31, 2011
Current income taxes
Federal		$  19,604
Total current income taxes		19,604
Deferred income taxes
Federal		(2,747)
Total deferred income taxes		(2,747)
Total income tax expense		$  16,857

The following table summarizes the reconciliation of the federal statutory tax rate to the effective tax rate for the MGR assets:

thousands, except percentages	Year Ended   December 31, 2011
Income before income taxes		$  48,160
Statutory tax rate		0%
Tax computed at statutory rate		—
Adjustments resulting from:
Federal taxes on income attributable to MGR assets		16,857
Income tax expense		$  16,857
Effective tax rate		35%

12

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

4.  INCOME TAXES (CONTINUED)

The tax effects of temporary differences that give rise to deferred tax assets (liabilities) for the MGR assets at December 31, 2011, are as follows:

thousands	December 31, 2011
Depreciable properties		$    82,166
Partnership basis		24,481
Other		(143)
Net long-term deferred income tax liabilities		106,504
Total net deferred income tax liabilities		$  106,504

5.  PROPERTY, PLANT AND EQUIPMENT

A summary of the historical cost of MGR’s property, plant and equipment is as follows:

		$281,290		$281,290
thousands	Estimated     useful life		December 31, 2011
Land		n/a		$            10
Gathering systems		5 to 47 years		405,415
Pipeline and equipment		15 to 45 years		6,165
Assets under construction		n/a		2,267
Other		25 years		356
Total property, plant and equipment				414,213
Accumulated depreciation				132,923
Net property, plant and equipment				$  281,290

The cost of property classified as “Assets under construction” is excluded from capitalized costs being depreciated. These amounts represent property that is not yet suitable to be placed into productive service as of the balance sheet date. In addition, property, plant and equipment cost, as well as third-party accrued liability balances in the MGR assets’ accompanying balance sheet as of December 31, 2011, includes $0.1 million of accrued capital, representing estimated capital expenditures for which invoices had not yet been processed.

6.  ASSET RETIREMENT OBLIGATIONS

The following table provides a summary of changes in asset retirement obligations:

thousands	December 31, 2011
Carrying amount of asset retirement obligations at beginning of year		$  3,876
Liabilities incurred		45
Liabilities settled		(3)
Accretion expense		263
Carrying amount of asset retirement obligations at end of year		$  4,181

13

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

7.  COMMITMENTS AND CONTINGENCIES

Environmental obligations. The MGR assets are subject to various environmental-remediation obligations arising from federal, state and local regulations regarding air and water quality, hazardous and solid waste disposal and other environmental matters. The accompanying balance sheet as of December 31, 2011, included a $0.1 million current liability and a $0.2 million long-term liability for remediation and reclamation obligations, included in accrued liabilities and asset retirement obligations and other, respectively. The recorded obligations do not include any anticipated insurance recoveries. Substantially all of the payments related to these obligations are expected to be made over the next five years. Management regularly monitors the remediation and reclamation process and the liabilities recorded and believes the environmental obligations related to the MGR assets are adequate to fund remedial actions to comply with present laws and regulations, and that the ultimate liability for these matters, if any, will not differ materially from recorded amounts nor materially affect the overall results of operations, cash flows or financial condition of the MGR assets. There can be no assurance, however, that current regulatory requirements will not change, or past non-compliance with environmental issues will not be discovered.

Litigation and legal proceedings. From time to time, MGR is involved in legal, tax, regulatory and other proceedings in various forums regarding performance, contracts and other matters that arise in the ordinary course of business. Management is not aware of any such proceedings for which a final disposition could have a material adverse effect on the results of operations, cash flows or financial position as of and for the year ended December 31, 2011 for the MGR assets.

Lease commitments. Rent expense associated with shared field offices and equipment leases was approximately $1.8 million for the year ended December 31, 2011. The MGR assets’ remaining contractual lease obligations as of December 31, 2011, represent month-to-month leases for compression equipment.

8.  SUBSEQUENT EVENT

Acquisition of the MGR assets by Western Gas Partners, LP. On January 13, 2012, the Partnership completed the MGR acquisition effective January 1, 2012. In conjunction with the acquisition, the Partnership entered into commodity price swap agreements with Anadarko in December 2011, each agreement effective for one year, beginning January 1, 2012, and extending through December 31, 2016, to mitigate exposure to commodity price volatility that would otherwise be present as a result of the purchase and sale of natural gas, condensate or NGLs. The commodity price swap agreements do not contain fixed notional volumes, do not satisfy the definition of a derivative financial instrument and are not required to be measured at fair value. Below is a summary of the fixed prices on the Partnership’s commodity price swap agreements for the MGR assets:

	Year Ended December 31,
per barrel except natural gas	2012		2013		2014		2015		2016
Ethane	$	26.87	$	25.34	$	24.10	$	23.41	$	23.11
Propane	$	57.97	$	55.59	$	53.78	$	52.99	$	52.90
Isobutane	$	80.98	$	77.66	$	75.13	$	74.02	$	73.89
Normal butane	$	71.15	$	68.24	$	66.01	$	65.04	$	64.93
Natural gasoline	$	89.51	$	85.84	$	83.04	$	81.82	$	81.68
Condensate	$	89.51	$	85.84	$	83.04	$	81.82	$	81.68
Natural gas (per MMbtu)	$	3.62	$	4.17	$	4.45	$	4.66	$	4.87

14

MGR ASSETS

NOTES TO FINANCIAL STATEMENTS

8.  SUBSEQUENT EVENT (CONTINUED)

Affiliate gathering agreements. In connection with the MGR acquisition, the Partnership entered into 10-year, fee-based gathering and processing agreements with Anadarko effective December 1, 2011, for all affiliate throughput on the MGR assets.

Agreements with Anadarko. From and after the closing of the MGR acquisition and related transactions, the MGR assets are subject to the terms and conditions of various agreements between the Partnership and Anadarko, including the following:

— an omnibus agreement that provides for certain indemnifications, reimbursement for expenses paid by Anadarko on behalf of the Partnership and compensation to Anadarko for providing the Partnership with certain general and administrative services and insurance coverage;

— a services and secondment agreement pursuant to which specified employees of Anadarko are seconded to the general partner to provide operating, routine maintenance and other services with respect to the assets owned and operated by the Partnership under the direction, supervision and control of the general partner;

— a tax sharing agreement pursuant to which the Partnership will reimburse Anadarko for the Partnership’s share of Texas margin tax borne by Anadarko as a result of the MGR assets’ financial results being included in a combined or consolidated tax return filed by Anadarko with respect to periods subsequent to January 1, 2012;

— a subsidiary guarantor agreement of partnership debt, from and after the closing of the MGR acquisition, MGR will be a subsidiary guarantor of (i) the Partnership’s $500 million in senior unsecured notes, and (ii) obligations created under the Partnership’s $800 million revolving credit facility; and

— other routine agreements with Anadarko or its subsidiaries that arise in the ordinary course of business for gathering, processing, treating and compression services and other operational matters.

Change in tax status. From and after closing of the MGR acquisition, the MGR assets will be consolidated by the Partnership, which generally is not subject to federal income tax, thereby eliminating the applicability of entity-level federal income taxation for income attributable to the MGR assets.

Affiliated balances subsequent to acquisition. Prior to January 1, 2012, cash transactions attributable to the MGR assets were received or paid in cash by Anadarko within its centralized cash management system. In connection with the closing of the Contribution Agreement, net affiliate receivable and payable balances with Anadarko were settled through an adjustment to parent net equity. Subsequent to January 1, 2012, the Partnership cash-settles transactions directly with third parties and Anadarko, including transactions attributable to the MGR assets, and no interest is charged or earned on affiliate balances other than balances associated with loan agreements.

15

EX-99.2

EXHIBIT 99.2

WESTERN GAS PARTNERS, LP

INDEX TO UNAUDITED PRO FORMA CONDENSED CONSOLIDATED

FINANCIAL STATEMENTS

Introduction	2
Unaudited Pro Forma Condensed Consolidated Statement of Income for the Year Ended December 31, 2011	4
Unaudited Pro Forma Condensed Consolidated Balance Sheet as of December 31, 2011	5
Notes to Unaudited Pro Forma Condensed Consolidated Financial Statements	6

INTRODUCTION

The unaudited pro forma condensed consolidated financial statements present the impact on Western Gas Partners, LP’s (collectively with its subsidiaries, the “Partnership”) results of operations and financial position attributable to the acquisition of certain midstream assets from affiliates of Anadarko Petroleum Corporation pursuant to the Contribution Agreement dated as of December 15, 2011 (the “MGR Contribution Agreement”), with an effective date for accounting purposes of January 1, 2012. The Partnership’s general partner is Western Gas Holdings, LLC (the “general partner” or “GP”), a wholly owned subsidiary of Anadarko Petroleum Corporation. “Anadarko” or “Parent” refers to Anadarko Petroleum Corporation and its consolidated subsidiaries, excluding the Partnership and the general partner; and “affiliates” refers to wholly owned and partially owned subsidiaries of Anadarko, excluding the Partnership.

Pursuant to the MGR Contribution Agreement, the Partnership acquired a 100% ownership interest in Mountain Gas Resources, LLC, which owns the Red Desert Complex (“Red Desert”), a 22% interest in Rendezvous Gas Services, LLC (“Rendezvous”) and certain additional midstream assets and equipment. Red Desert, located in the greater Green River Basin in southwestern Wyoming, includes the Patrick Draw processing plant, the Red Desert processing plant, 1,295 miles of gathering lines and related facilities. Rendezvous owns a 338-mile mainline gathering system serving the Jonah and Pinedale Anticline fields in southwestern Wyoming, which delivers gas to the Granger complex and other locations. The acquired assets are referred to collectively as the “MGR assets” or “MGR,” and the acquisition is referred to as the “MGR acquisition.”

The contribution of the MGR assets to the Partnership was recorded at Anadarko’s historical cost as this transaction is considered a reorganization of entities under common control. After the acquisition of assets from Anadarko, the Partnership is required to revise its financial statements to include the activities of the acquired assets as of the date of common control.

The unaudited pro forma condensed consolidated statement of income for the year ended December 31, 2011, and the unaudited pro forma condensed consolidated balance sheet as of December 31, 2011, are based upon the historical consolidated financial statements of the Partnership, as presented in the Partnership’s Form 10-K for the year ended December 31, 2011, and the historical financial statements of the MGR assets, as presented in Exhibit 99.1 of this Current Report on Form 8-K/A. The unaudited pro forma condensed consolidated statement of income for the year ended December 31, 2011, has been prepared as if the MGR acquisition occurred on January 1, 2011. The unaudited pro forma condensed consolidated balance sheet has been prepared as if the MGR acquisition occurred on December 31, 2011. The unaudited pro forma condensed consolidated financial statements have been prepared based on the assumption that the Partnership will continue to be treated as a partnership for U.S. federal and state income tax purposes and therefore will not be subject to U.S. federal income taxes and state income taxes, except for the Texas margin tax. The unaudited pro forma condensed consolidated financial statements have also been prepared based on certain pro forma adjustments as described in Note 2. Pro Forma Adjustments.

The audited historical financial statements of the MGR assets as set forth in Exhibit 99.1 of this Current Report on Form 8-K/A as of and for the year ended December 31, 2011, and the Partnership’s audited historical consolidated financial statements as set forth in its Form 10-K as of and for the year ended December 31, 2011, as filed with the U.S. Securities and Exchange Commission, are qualified in their entirety by reference to such historical financial statements and related notes contained in those reports. The unaudited pro forma condensed consolidated financial statements should be read in conjunction with the historical financial statements and related notes thereto.

2

INTRODUCTION (CONTINUED)

The pro forma adjustments reflected in the unaudited pro forma condensed consolidated financial statements are based upon currently available information and certain assumptions and estimates; therefore, the actual effects of these transactions will differ from the pro forma adjustments. However, the Partnership’s management considers the applied estimates and assumptions to provide a reasonable basis for the presentation of the significant effects of certain transactions that are expected to have a continuing impact on the Partnership. In addition, the Partnership’s management considers the pro forma adjustments to be factually supportable and to appropriately represent the expected impact of items that are directly attributable to the transfer of the MGR assets to the Partnership.

The pro forma adjustments included in the unaudited pro forma condensed consolidated financial statements reflect the MGR acquisition, including the following significant transactions:

• the Partnership’s $299.0 million of borrowings under its revolving credit facility to partially finance the MGR acquisition;

• the Partnership’s use of $159.6 million of cash-on-hand to fund a portion of the cash consideration paid to Anadarko for the MGR acquisition;

• the Partnership’s issuance of 632,783 common units and 12,914 general partner units to Anadarko in connection with the MGR acquisition; and

• Anadarko’s contribution of the MGR assets to the Partnership.

From and after the closing of the MGR acquisition and related transactions, the MGR assets will be subject to the terms and conditions of various agreements between the Partnership and Anadarko, including the following:

• an omnibus agreement that provides for certain indemnifications, reimbursement for expenses paid by Anadarko on behalf of the Partnership and compensation to Anadarko for providing the Partnership with certain general and administrative services and insurance coverage;

• a services and secondment agreement pursuant to which specified employees of Anadarko are seconded to the general partner to provide operating, routine maintenance and other services with respect to the assets owned and operated by the Partnership under the direction, supervision and control of the general partner;

• a tax sharing agreement pursuant to which the Partnership will reimburse Anadarko for the Partnership’s estimated share of Texas margin tax borne by Anadarko as a result of the MGR assets’ financial results being included in a combined or consolidated tax return filed by Anadarko with respect to periods subsequent to January 1, 2012;

• a subsidiary guarantor agreement of partnership debt, from and after the closing of the MGR acquisition, MGR will be a subsidiary guarantor of (i) the Partnership’s $500 million in senior unsecured notes, and (ii) obligations created under the Partnership’s $800 million revolving credit facility; and

• other routine agreements with Anadarko or its subsidiaries that arise in the ordinary course of business for gathering, processing, treating, transportation and compression services and other operational matters.

The unaudited pro forma condensed consolidated financial statements are not necessarily indicative of the results that would have occurred if the Partnership had acquired the MGR assets on the dates indicated nor are they indicative of the future operating results of the Partnership.

3

WESTERN GAS PARTNERS, LP

PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF INCOME

YEAR ENDED DECEMBER 31, 2011

(UNAUDITED)

thousands except per-unit amounts	Partnership Historical		MGR Assets Historical		Pro Forma Adjustments			Partnership Pro Forma
Revenues – affiliates
Gathering, processing and transportation of natural gas and natural gas liquids		$  216,445		$      1,783		$      (376)	(a)		$  217,852
Natural gas, natural gas liquids and condensate sales		276,746		140,801		—			417,547
Equity income and other, net		12,427		1,171		—			13,598
Total revenues – affiliates		505,618		143,755		(376)			648,997
Revenues – third parties
Gathering, processing and transportation of natural gas and natural gas liquids		70,524		12,954		—			83,478
Natural gas, natural gas liquids and condensate sales		84,836		—		—			84,836
Other, net		3,102		2,851		—			5,953
Total revenues – third parties		158,462		15,805		—			174,267
Total revenues		664,080		159,560		(376)			823,264
Operating expenses
Cost of product (1)		247,302		80,443		(376)	(a)		327,369
Operation and maintenance (1)		101,754		17,351		—			119,105
General and administrative (1)		35,388		3,725		(772)	(b)		38,341
Property and other taxes		15,695		885		—			16,580
Depreciation, amortization and impairments		88,454		23,450		—			111,904
Total operating expenses		488,593		125,854		(1,148)			613,299
Operating income		175,487		33,706		772			209,965
Interest income – affiliates		16,900		12,874		(12,874)	(c)		16,900
Interest expense (2)		(31,559)		—		(5,366)	(d)		(36,925)
Other income (expense), net		(1,624)		1,580		—			(44)
Income before income taxes		159,204		48,160		(17,468)			189,896
Income tax expense		2,161		16,857		(18,229)	(e)		789
Net income		157,043		31,303		761			189,107
Net income attributable to noncontrolling interests		14,103		—		—			14,103
Net income attributable to Western Gas Partners, LP		$  142,940		$    31,303		$         761			$  175,004
Pre-acquisition net income allocated to Parent		$      2,781							$      2,781
General partner interest in net income (3)		$      8,599							$      9,281
Limited partners’ interest in net income		$  131,560							$  162,942
Net income per common unit – basic and diluted		$        1.64							$        2.02
Net income per subordinated unit – basic and diluted (4)		$        1.28							$        1.56
Weighted average units outstanding - basic and diluted
Common units		67,333							67,966
Subordinated units (4)		16,431							16,431

⁽¹⁾  As it relates to Partnership financial statements, cost of product includes product purchases from Anadarko (as defined in the Introduction) of $75.9 million, operation and maintenance includes charges from Anadarko of $44.1 million, and general and administrative includes charges from Anadarko of $28.1 million for the year ended December 31, 2011.

⁽²⁾  Partnership financial statements include affiliate (as defined in the Introduction) interest expense of $6.1 million for year ended December 31, 2011.

⁽³⁾  Partnership historical information represents net income for periods including and subsequent to the acquisition of the assets owned by the Partnership as of December 31, 2011.

⁽⁴⁾  All subordinated units were converted to common units on a one-for-one basis on August 15, 2011. For purposes of calculating net income per common and subordinated unit, the conversion of the subordinated units is deemed to have occurred on July 1, 2011. See Note 3.

See accompanying Notes to Unaudited Pro Forma Condensed Consolidated Financial Statements.

4

WESTERN GAS PARTNERS, LP

PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET

AS OF DECEMBER 31, 2011

(UNAUDITED)

thousands	Partnership Historical		MGR Assets Historical		Pro Forma Adjustments			Partnership Pro Forma
ASSETS
Current assets
Cash and cash equivalents		$    226,559		$           —		$   299,000	(f)		$       66,972
						(458,587)	(f)
Accounts receivable, net		22,197		506		—			22,703
Other current assets (1)		6,794		392		—			7,186
Total current assets		255,550		898		(159,587)			96,861
Note receivable – Anadarko		260,000		—		—			260,000
Plant, property and equipment
Cost		2,223,800		414,213		—			2,638,013
Less accumulated depreciation		452,866		132,923		—			585,789
Net property, plant and equipment		1,770,934		281,290		—			2,052,224
Goodwill and other intangible assets		116,994		18,000		—			134,994
Equity investments		39,978		69,839		—			109,817
Other assets		8,164		15,979		—			24,143
Total assets		$  2,451,620		$  386,006		$  (159,587)			$  2,678,039
LIABILITIES, EQUITY AND PARTNERS’ CAPITAL
Current liabilities
Accounts and natural gas imbalance payables (2)		$       25,744		$        856		$            —			$       26,600
Accrued ad valorem taxes		7,882		304		—			8,186
Income taxes payable		495		—		124	(e)		619
Accrued liabilities (3)		36,973		4,342		—			41,315
Total current liabilities		71,094		5,502		124			76,720
Long-term debt – third parties		494,178		—		299,000	(f)		793,178
Note payable – Anadarko		175,000		—		—			175,000
Deferred income taxes		873		106,504		(106,504)	(e)		873
Asset retirement obligations and other		62,769		4,400		—			67,169
Total long-term liabilities		732,820		110,904		192,496			1,036,220
Total liabilities		803,914		116,406		192,620			1,112,940
Equity and partners’ capital
Common units		1,495,253		—		(83,090)	(f)		1,412,163
General partner units		31,729		—		483	(f)		32,212
Parent net investment		—		269,600		(375,979)	(f)		—
						106,379	(e)
Total partners’ capital		1,526,982		269,600		(352,207)			1,444,375
Noncontrolling interests		120,724		—		—			120,724
Total equity and partners’ capital		1,647,706		269,600		(352,207)			1,565,099
Total liabilities, equity and partners’ capital		$  2,451,620		$  386,006		$  (159,587)			$  2,678,039

⁽¹⁾  As it relates to Partnership financial statements, other current assets includes natural gas imbalance receivables from affiliates of $0.5 million as of December 31, 2011.

⁽²⁾  As it relates to Partnership financial statements, accounts and natural gas imbalance payables includes amounts payable to affiliates of $5.9 million as of December 31, 2011.

⁽³⁾  As it relates to Partnership financial statements, accrued liabilities includes amounts payable to affiliates of $0.3 million as of December 31, 2011.

See accompanying Notes to Unaudited Pro Forma Condensed Consolidated Financial Statements.

5

WESTERN GAS PARTNERS, LP

NOTES TO UNAUDITED PRO FORMA CONDENSED CONSOLIDATED

FINANCIAL STATEMENTS

1. BASIS OF PRESENTATION

The unaudited pro forma condensed consolidated financial statements are based upon the audited historical consolidated financial statements of the Partnership and the audited historical financial statements of the MGR assets. The unaudited pro forma condensed consolidated financial statements present the impact of the MGR acquisition, which is described in the Introduction, on the Partnership’s results of operations and financial position. The contribution of the MGR assets to the Partnership was recorded at Anadarko’s historical cost as this transaction is considered a reorganization of entities under common control.

2. PRO FORMA ADJUSTMENTS

The following adjustments for the Partnership have been prepared (i) as if the MGR acquisition occurred on January 1, 2011, in the case of the unaudited pro forma condensed consolidated statement of income for the year ended December 31, 2011, and (ii) as if the MGR acquisition occurred on December 31, 2011, in the case of the unaudited pro forma condensed consolidated balance sheet as of December 31, 2011:

a) The elimination of intercompany gathering revenue and cost of product between the Partnership and the MGR assets;

b) The elimination of transaction costs included in the historical financial statements of the Partnership which are directly related to the MGR acquisition;

c) The elimination of historical interest income, net resulting from the non-cash settlement of receivables and payables from or owed to Anadarko prior to the acquisition of the MGR assets;

d) The inclusion of interest expense on the Partnership’s $299.0 million of borrowings under the Partnership’s revolving credit facility, which bears interest at a variable rate, to partially finance the MGR acquisition;

e) The elimination of historical current and deferred income taxes, as the Partnership is generally not subject to federal and state income taxes, other than Texas margin tax. Texas margin taxes that continue to be borne by the Partnership on the portion of the Partnership’s pro forma income that is allocable to Texas, have not been eliminated;

f) The acquisition of the MGR assets by the Partnership, including the payment of $458.6 million of cash (representing $159.6 million of cash on hand and $299.0 million borrowed under its revolving credit facility) and the issuance of 632,783 common units and 12,914 general partner units to Anadarko. The excess of cash consideration paid over the historical net book value of assets acquired and liabilities assumed is recorded as a decrease to partners’ capital for the common unitholders and the general partner.

In connection with the MGR acquisition, the Partnership entered into 10-year, fee-based gathering and processing agreements with Anadarko effective on December 1, 2011 for all affiliate throughput on the MGR assets. Also, in connection with the MGR acquisition, the Partnership entered into commodity price swap agreements with Anadarko, each agreement effective for one year, beginning January 1, 2012, and extending through December 31, 2016, to mitigate exposure to commodity price volatility that would otherwise be present as a result of the Partnership’s acquisition of the MGR assets. The impact of the fee-based gathering agreements and the commodity price swap agreements is not reflected in the unaudited pro forma condensed consolidated financial statements.

6

WESTERN GAS PARTNERS, LP

NOTES TO UNAUDITED PRO FORMA CONDENSED CONSOLIDATED

FINANCIAL STATEMENTS

3. PRO FORMA NET INCOME PER UNIT

Earnings per unit is calculated based on the assumption that the Partnership distributes to its unitholders an amount of cash equal to net income attributable to Western Gas Partners, LP, notwithstanding the general partner’s ultimate discretion over the amount of cash to be distributed for the period, the existence of other legal or contractual limitations that would prevent distributions of all of the net income for the period or any other economic or practical limitation on the ability to make a full distribution of all of the net income for the period. Earnings per unit is calculated by applying the provisions of the partnership agreement that govern actual cash distributions to the notional cash distribution amount, including giving effect to incentive distributions, when applicable. The allocation of undistributed earnings, or net income attributable to Western Gas Partners, LP in excess of distributions, to the incentive distribution rights is limited to available cash (as defined by the partnership agreement) for the period.

From its inception through June 30, 2011, the Partnership paid equal distributions per unit on common, subordinated and general partner units. Upon payment of the cash distribution for the second quarter of 2011, the financial requirements for the conversion of all subordinated units were satisfied. As a result, the 26,536,306 subordinated units were converted on August 15, 2011, on a one-for-one basis, into common units. For purposes of calculating net income per common and subordinated unit, the conversion of the subordinated units is deemed to have occurred on July 1, 2011. The Partnership’s net income was allocated to the general partner and the limited partners, including the holders of the subordinated units, through June 30, 2011, in accordance with their respective ownership percentages. The conversion does not impact the amount of the cash distribution paid or the total number of the Partnership’s outstanding units representing limited partner interests.

For purposes of calculating pro forma net income per unit, management assumed that annual pro forma cash distributions were equal to annual pro forma earnings. Pro forma basic and diluted net income per unit is calculated by dividing the limited partners’ interest in net income by the number of units outstanding as of December 31, 2011. The pro forma weighted average number of common units and general partner units outstanding are based on the weighted average number of units outstanding during the year ended December 31, 2011, adjusted to give effect to the common units and general partner units issued in connection with the MGR acquisition as if such units were issued on January 1, 2011.

Pursuant to the limited partnership agreement, to the extent that the quarterly distributions exceed certain targets, the general partner is entitled to receive certain incentive distributions that will result in more net income being proportionately allocated to the general partner than to the holders of common and subordinated units. The pro forma net income per unit would have been sufficient to generate incentive distribution payments to our general partner and the effect of such incentive distributions are reflected in the pro forma net income per unit for the year ended December 31, 2011. However, because (i) the partnership agreement requires the Partnership to distribute available cash rather than the earnings reflected in the Partnership’s income statement and (ii) the pro forma net income per unit calculation has been prepared on a year-to-date basis in lieu of a quarterly basis, actual cash distributions declared and paid by the Partnership may vary significantly from reported pro forma net income per unit.

Immediately subsequent to the MGR acquisition, Anadarko held 1,852,527 general partner units, representing a 2.0% general partner interest in the Partnership, 100% of the Partnership incentive distribution rights and 40,422,004 common units, representing an aggregate 43.6% limited partner interest in the Partnership. The public held 50,351,778 common units, representing a 54.4% limited partner interest in the Partnership.

7

WESTERN GAS PARTNERS, LP

NOTES TO UNAUDITED PRO FORMA CONDENSED CONSOLIDATED

FINANCIAL STATEMENTS

3. PRO FORMA NET INCOME PER UNIT (CONTINUED)

The following table illustrates the Partnership’s calculation of pro forma net income per common and subordinated unit:

thousands except per-unit amounts	Year Ended December 31, 2011
Pro forma net income attributable to Western Gas Partners, LP		$  175,004
Less pre-acquisition net income allocated to Parent		2,781
Less general partner interest in pro forma net income		9,281
Limited partners’ interest in pro forma net income		$  162,942
Pro forma net income allocable to common units		$  137,234
Pro forma net income allocable to subordinated units		25,708
Limited partners’ interest in pro forma net income		$  162,942
Pro forma net income per unit – basic and diluted
Common units		$        2.02
Subordinated units		$        1.56
Pro forma weighted average units outstanding – basic and diluted
Common units		67,966
Subordinated units		16,431

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