Exhibit 1.1

Execution Version

Exhibit 1.1

Basic Energy Services, Inc.

Common Stock, par value $0.01

Underwriting Agreement

June 9, 2014

Goldman, Sachs & Co.,

1000 Louisiana Street

Suite 1100

Houston, Texas 77002

Ladies and Gentlemen:

Certain stockholders named in Schedule II hereto (the "Selling Stockholders") of Basic Energy Services, Inc., a Delaware corporation (the “Company”), propose, subject to the terms and conditions stated herein, to sell to Goldman, Sachs & Co. (the “Underwriter”) an aggregate of 6,000,000 shares (the “Firm Shares”) and, at the election of the Underwriter, up to 900,000 additional shares (the “Optional Shares”) of Common Stock, par value $0.01 (“Stock”) of the Company (the Firm Shares and the Optional Shares that the Underwriter elects to purchase pursuant to Section 2 hereof are herein collectively called the “Shares”).

1.(a)The Company represents and warrants to, and agrees with, the Underwriter that:

(i)A registration statement on Form S-3 (File No. 333-180673) in respect of the Shares has been filed with the Securities and Exchange Commission (the “Commission”); and no stop order suspending the effectiveness of such registration statement or any part thereof has been issued and no proceeding for that purpose has been initiated or threatened by the Commission, and no notice of objection of the Commission to the use of such registration statement or any post-effective amendment thereto pursuant to Rule 401(g)(2) under the Securities Act of 1933, as amended (the “Act”) has been received by the Company (the base prospectus filed as part of such registration statement, in the form in which it has most recently been filed with the Commission on or prior to the date of this Underwriting Agreement (the “Agreement”), is hereinafter called the “Basic Prospectus”; any preliminary prospectus (including any preliminary prospectus supplement) relating to the Shares filed with the Commission pursuant to Rule 424(b) under the Act is hereinafter called a “Preliminary Prospectus”; the various parts of such registration statement, including all exhibits thereto and including any prospectus supplement relating to the Shares that is filed with the Commission and deemed by virtue of Rule 430B to be part of such registration statement, each as amended at the time such part of the registration statement became effective, are hereinafter collectively called the “Registration Statement”; the Basic Prospectus, as amended and supplemented immediately prior to the Applicable Time is hereinafter called the “Pricing Prospectus”; the form of the final prospectus relating to the Shares filed with the Commission pursuant to Rule 424(b) under the Act in accordance with Section 5(a) hereof is hereinafter called the “Prospectus”; any reference herein to

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the Basic Prospectus, the Pricing Prospectus, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the Act, as of the date of such prospectus; any reference to any amendment or supplement to the Basic Prospectus, any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include any post-effective amendment to the Registration Statement, any prospectus supplement relating to the Shares filed with the Commission pursuant to Rule 424(b) under the Act and any documents filed under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and incorporated therein, in each case after the date of the Basic Prospectus, such Preliminary Prospectus, or the Prospectus, as the case may be; any reference to any amendment to the Registration Statement shall be deemed to refer to and include the most recent annual report of the Company filed pursuant to Section 13(a) or 15(d) of the Exchange Act that is incorporated by reference in the Registration Statement; and any “issuer free writing prospectus” as defined in Rule 433 under the Act relating to the Shares is hereinafter called an “Issuer Free Writing Prospectus”). For purposes of this Agreement, the “Applicable Time” is 5:45 P.M. (Eastern time) on the date of this Agreement;

(ii)No order preventing or suspending the use of any Preliminary Prospectus or any Issuer Free Writing Prospectus has been issued by the Commission, and each Preliminary Prospectus, at the time of filing thereof, conformed in all material respects to the applicable requirements of the Act and the rules and regulations of the Commission thereunder, and did not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by the Underwriter expressly for use therein or by a Selling Stockholder expressly for use in the preparation of the answers therein to Item 7 of Form S‑3;

(iii)The documents incorporated by reference in the Pricing Prospectus and the Prospectus, when they became effective or were filed with the Commission, as the case may be, conformed in all material respects to the requirements of the Act or the Exchange Act, as applicable, and the rules and regulations of the Commission thereunder, and none of such documents contained an untrue statement of a material fact or omitted to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; any further documents so filed and incorporated by reference in the Prospectus or any further amendment or supplement thereto, when such documents become effective or are filed with the Commission, as the case may be, will conform in all material respects to the requirements of the Act or the Exchange Act, as applicable, and the rules and regulations of the Commission thereunder and will not contain an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by the Underwriter expressly for use therein; and no such documents were filed with the Commission since the Commission’s close of business on the Business Day (as defined herein) immediately prior to the date of this Agreement and prior to the execution of this Agreement, except as set forth on Schedule IV hereto;

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(iv)The Registration Statement conforms, and the Prospectus and any further amendments or supplements to the Registration Statement or the Prospectus will conform, in all material respects to the applicable requirements of the Act and the rules and regulations of the Commission thereunder and do not and will not, as of the applicable effective date as to the Registration Statement and any amendment thereto and as of the applicable filing date as to the Prospectus and any amendment or supplement thereto, contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by the Underwriter expressly for use therein or by a Selling Stockholder expressly for use in the preparation of the answers therein to Item 7 of Form S‑3;

(v)Neither the Company nor any of its Subsidiaries (as defined herein) has sustained since the date of the latest audited financial statements included in or incorporated by reference into the Pricing Prospectus any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, other than as set forth or contemplated in the Pricing Prospectus; and, since the respective dates as of which information is given in the Registration Statement and the Pricing Prospectus, there has not been any change in the capital stock (other than issuances of capital stock in the ordinary course of business pursuant to the Company’s employee benefit plans or upon the exercise of outstanding options issued under such plans) or long-term debt of the Company or any of its Subsidiaries or any Material Adverse Effect, or any development involving a prospective Material Adverse Effect, in or affecting the general affairs, management, financial position, stockholders' equity or results of operations of the Company and its Subsidiaries, otherwise than as set forth or contemplated in the Pricing Prospectus. A “Material Adverse Effect” means (x) a material adverse effect on the business, condition (financial or other), results of operations, prospects or properties of the Company and the Subsidiaries, taken as a whole or (y) an adverse effect on the ability of the Company to consummate the transactions contemplated hereby on a timely basis;

(vi)The Company has an authorized capitalization as set forth in the Pricing Prospectus, and all of the issued shares of capital stock of the Company, including the Shares to be sold by the Selling Stockholder, have been duly and validly authorized and issued, are fully paid and non-assessable and conform to the description of the Stock contained in the Pricing Prospectus; and all of the issued shares of capital stock of each subsidiary of the Company (each a “Subsidiary” and, together, the “Subsidiaries”) have been duly and validly authorized and issued, are fully paid and non-assessable and (except for directors’ qualifying shares and except as set forth in the Pricing Prospectus) are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims, except for such liens or encumbrances on such capital stock to secure indebtedness of the Company’s Subsidiaries as described in the Pricing Prospectus;

(vii)Each of the Company and each Subsidiary (A) is a corporation, limited liability company, partnership or other entity duly organized and validly existing under the laws of the jurisdiction of its organization, (B) has all requisite corporate or other power and authority necessary to own its property and carry on its business as now being conducted and (C) is qualified to do business and is in good standing in all jurisdictions

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in which the nature of the business conducted by it or its ownership of property makes such qualification necessary, except where the failure to be so qualified and be in good standing, individually or in the aggregate, would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect;

(viii)The Company has all requisite corporate power and authority to execute, deliver and perform all of its obligations under this Agreement and to consummate the transactions contemplated;

(ix)This Agreement has been duly and validly authorized, executed and delivered by the Company;

(x)Neither the Company nor any Subsidiary is (A) in violation of its charter, bylaws or other constitutive documents, (B) in default (or, with notice or lapse of time or both, would be in default) in the performance or observance of any obligation, agreement, covenant or condition contained in any bond, debenture, note, indenture, mortgage, deed of trust, loan or credit agreement, lease, license, franchise agreement, authorization, permit, certificate or other agreement or instrument to which any of them is a party or by which any of them is bound or to which any of their assets or properties is subject (collectively, “Agreements and Instruments”), or (C) in violation of any law, statute (including, without limitation, any rule or regulation) or any judgment, order or decree of any domestic or foreign court or other governmental or regulatory authority, agency or other body with jurisdiction over any of them or any of their assets or properties (“Governmental Authority”), except, in the case of clauses (B) and (C), for such defaults or violations as could not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect;

(xi)The execution, delivery and performance of this Agreement by the Company and the consummation of the transactions contemplated hereby does not and will not (A) violate the charter, bylaws or other constitutive documents of the Company or any Subsidiary, (B) conflict with or constitute a breach of or a default under (or an event that with notice or the lapse of time, or both, would constitute a default), or require consent under, or result in a Repayment Event (as defined herein), other than a Repayment Event that will be satisfied at each Time of Delivery (as defined in Section 4 hereof) as contemplated by the Pricing Prospectus or the Prospectus, or the creation or imposition of a lien, charge or encumbrance on any property or assets of the Company or any Subsidiary under any of the Agreements and Instruments or (C) violate any law, statute, rule or regulation, or any judgment, order or decree of any Governmental Authority, except for such conflicts, violations, breaches or defaults in the cases of clauses (B) and (C) that would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect. No consent, approval, authorization or order of, or filing, registration, qualification, license or permit of or with, any Governmental Authority is required to be obtained or made by the Company or any Subsidiary for the execution, delivery and performance by the Company of this Agreement and the consummation of the transactions contemplated hereby, except such as have been or will be obtained or made on or prior to each Time of Delivery. No consents or waivers from any other person or entity are required for the execution, delivery and performance of this Agreement and the consummation of the transactions contemplated hereby, other than such consents and waivers as have been obtained or will be obtained prior to each Time of Delivery and will be in full force and effect. As used herein, a “Repayment Event” means any event or condition which gives the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to

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require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any Subsidiary;

(xii)Except as otherwise disclosed in the Pricing Prospectus and the Prospectus, there are no outstanding loans, advances (except advances for business expenses in the ordinary course of business) or guarantees of indebtedness by the Company or any affiliate of the Company to or for the benefit of any of the officers or directors of the Company or any affiliate of the Company or any of their respective family members;

(xiii)The public accountants whose report is included in or incorporated by reference into the Pricing Prospectus and the Prospectus are independent within the meaning of the Act. The historical consolidated financial statements (including the notes thereto) included in or incorporated by reference into the Pricing Prospectus and the Prospectus present fairly in all material respects the consolidated financial position, results of operations, cash flows and changes in stockholder’s equity of the Company at the respective dates and for the respective periods indicated. All such financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) applied on a consistent basis throughout the periods presented (except as disclosed therein) and in compliance with Regulation S-X (“Regulation S-X”) under the Exchange Act. The other financial information, including but not limited to non-GAAP financial measures, if any, included in or incorporated by reference into the Pricing Prospectus and the Prospectus, have been prepared in good faith and on a reasonable basis consistent with that of the unaudited financial statements of the Company. Since the date as of which information is given in the Pricing Prospectus, except as set forth in the Pricing Prospectus and the Prospectus, (A) neither the Company nor any Subsidiary has (1) incurred any liabilities or obligations, direct or contingent, that would, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect, or (2) entered into any material transaction not in the ordinary course of business, (B) there has not been any event or development in respect of the business or condition (financial or other) of the Company or any Subsidiary that, either individually or in the aggregate, would reasonably be expected to have a Material Adverse Effect, (C) there has been no dividend or distribution of any kind declared, paid or made by the Company on any of its equity interests and (D) there has not been any change in the long-term debt of the Company or any Subsidiary other than changes due to ordinary course of business capital leases. The interactive data in extensible Business Reporting Language incorporated by reference in the Pricing Prospectus and the Prospectus fairly presents the information called for in all material respects and has been prepared in accordance with the Commission’s rules and guidelines applicable thereto;

(xiv)The statistical and market-related data and forward-looking statements included in the Pricing Prospectus and the Prospectus are based on or derived from sources that the Company believes to be reliable and accurate in all material respects and represent their good faith estimates that are made on the basis of data derived from such sources. The Company has obtained the written consent to the use of such data from such sources to the extent required;

(xv)Except as set forth in the Pricing Prospectus and the Prospectus, there is (A) no action, suit or proceeding before or by any Governmental Authority or arbitrator, now pending or, to the knowledge of the Company, threatened or contemplated, to which the Company or any Subsidiary is or may be a party or to which the business, assets or property of the Company or any Subsidiary is or may be subject and (B) no judgment, decree or order of any Governmental Authority that, in either of clause (A) or (B), could

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reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect;

(xvi)Except as could not reasonably be expected to have a Material Adverse Effect, no labor disturbance by the employees of the Company or any Subsidiary exists or, to the knowledge of the Company, is imminent;

(xvii)Except as described in the Pricing Prospectus and the Prospectus and except for such matters as would not individually or in the aggregate have a Material Adverse Effect (A) none of the Company or any of its Subsidiaries is in violation of any federal, state, local or foreign statute, law, rule, regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof, including any judicial or administrative order, consent, decree or judgment, relating to pollution or protection of human health, the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation, laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum or petroleum products, asbestos-containing materials or mold (collectively, “Hazardous Materials”) or to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental Laws”), (B) the Company and its Subsidiaries have all permits, authorizations and approvals required under any applicable Environmental Laws and are each in compliance with their requirements, (C) there are no pending or, to the knowledge of the Company, threatened administrative, regulatory or judicial actions, suits, demands, demand letters, claims, liens, notices of noncompliance or violation, investigation or proceedings relating to any Environmental Law against the Company, or any of its Subsidiaries, and (D) to the knowledge of the Company, there are no events or circumstances that would reasonably be expected to form the basis of an order for clean-up or remediation, or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company or any of its Subsidiaries relating to Hazardous Materials or any Environmental Laws. In the ordinary course of its business, the Company conducts a periodic review of the effect of Environmental Laws on the business, operations and properties of the Company and its Subsidiaries, in the course of which it identifies and evaluates associated costs and liabilities (including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws or any permit, license or approval, any related constraints on operating activities and any potential liabilities to third parties). On the basis of such review and the amount of its established reserves, the Company has reasonably concluded that such associated costs and liabilities would not, individually or in the aggregate, result in a Material Adverse Effect;

(xviii)The Company and its Subsidiaries possess adequate certificates, authorities or permits issued by appropriate governmental agencies or bodies necessary to conduct the business now operated by them and have not received any notice of proceedings relating to the revocation or modification of any such certificate, authority or permit that, if determined adversely to the Company or any of its Subsidiaries, would individually or in the aggregate have a Material Adverse Effect;

(xix)The Company and the Subsidiaries have good and indefeasible title in fee simple to all items of owned real property, and good and marketable title to all personal property owned by each of them in each case free and clear of any pledge, lien, encumbrance, security interest or other defect or claim of any third party, except (A) such as would not reasonably be expected to have a Material Adverse Effect and (B) liens described in the Pricing Prospectus and the Prospectus. Any real property, personal property and buildings held under lease by any of them are held under valid, subsisting and enforceable leases, with such exceptions as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect;

(xx)Each of the Company and the Subsidiaries has insurance covering its properties, operations, personnel and business, including protection and indemnity insurance, which insurance is in amounts and insures against such losses and risks as are generally deemed adequate to protect each of the Company and the Subsidiaries and its business consistent with industry practice. All policies of insurance insuring the Company and its Subsidiaries or their businesses, assets, employees, officers and directors are in full force and effect, except where the failure to have such policies in full force and effect would not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect. Each of the Company and the Subsidiaries is in compliance with the terms of such policies and instruments in all material respects. Neither the Company nor any Subsidiary has been refused any insurance coverage sought or applied for, and the Company has no reason to believe that it or any of its Subsidiaries will not be able to renew existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that could not reasonably be expected, individually or in the aggregate, to have a Material Adverse Effect;

(xxi)All tax returns required to be filed by the Company or any Subsidiary have been filed (or extensions have been obtained) in all jurisdictions where such returns are required to be filed; and all taxes, including withholding taxes, value added and franchise taxes, penalties and interest, assessments, fees and other charges due or claimed to be due from such entities or that are due and payable have been paid, other than those being contested in good faith and for which reserves have been provided in accordance with GAAP or those currently payable without penalty or interest and except where the failure to make such required filings or payments could not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect;

(xxii)Neither the Company nor any Subsidiary is, or after giving effect to the transactions contemplated hereby will be, required to be registered as an “investment company” or a company “controlled” by an “investment company” within the meaning of the Investment Company Act of 1940, as amended;

(xxiii)The Company and the Subsidiaries maintain a system of internal accounting controls sufficient to provide reasonable assurance that: (A) transactions are executed in accordance with management’s general or specific authorizations; (B) transactions are recorded as necessary to permit preparation of their financial statements in conformity with GAAP and to maintain accountability for assets; (C) access to assets is permitted only in accordance with management’s general or specific authorization; and (D) the recorded accountability for their assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences;

(xxiv) The Company has established and maintains disclosure controls and procedures (as such term is defined in Rule 13a-15(e) under the Exchange Act); such disclosure controls and procedures are designed to ensure that material information relating to the Company and the Subsidiaries is made known to the chief executive officer and chief financial officer of the Company by others within the Company or any Subsidiary and such disclosure controls and procedures are reasonably effective to perform the functions for which they were established subject to the limitations of any such control system; the Company’s auditors and the audit committee of the board of directors of the Company have been advised of: (A) any significant deficiencies in the design or operation of internal controls which could adversely affect the Company’s ability to record, process, summarize, and report financial data; and (B) any fraud, whether or not material, that involves management or other employees who have a role in the Company’s internal controls; and since the date of the most recent evaluation of such disclosure controls and procedures, there have been no significant changes in internal controls or in other factors that could significantly affect internal controls, including any corrective actions with regard to significant deficiencies and material weaknesses;

(xxv)Except as described in the section entitled “Plan of Distribution" in the Pricing Prospectus and Prospectus, there are no contracts, agreements or understandings between the Company or any Subsidiary and any other person other than the Underwriter pursuant to this Agreement that would give rise to a valid claim against the Company, any Subsidiary or the Underwriter for a brokerage commission, finder’s fee or like payment in connection with the issuance, purchase and sale of the Shares;

(xxvi)The principal executive officer and principal financial officer of the Company have made all certifications required by the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith (the “Sarbanes-Oxley Act”). The Company is otherwise in compliance in all material respects with all applicable provisions of the Sarbanes-Oxley Act that are effective;

(xxvii)Neither the Company nor any of its Subsidiaries, nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the any of the Company or any of its Subsidiaries is currently the subject of any sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”);

(xxviii)None of the Company nor any of its Subsidiaries, nor, to the knowledge of the Company, any director, officer, agent, employee or other person associated with or acting on behalf of any of the Company or any of its Subsidiaries, has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; or (ii) violated or is in violation of any provision of the U.S. Foreign Corrupt Practices Act of 1977;

(xxix)The operations of the Company and its Subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all applicable jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending or, to the best knowledge of the Company, threatened; and

(xxx)There are no preemptive rights or other rights to subscribe for or to purchase, nor any restriction upon the voting or transfer of, any capital stock of the Company, pursuant to the constituent documents or any agreement or other instrument to which the Company is a party or by which it may be bound, except for such rights as have been effectively complied with, satisfied or waived. Neither the filing of the Registration Statement nor the offering or sale of the Shares as contemplated by this Agreement gives rise to any rights for or relating to the registration of any Stock or other securities of the Company, except for such rights as have been effectively complied with, satisfied or waived.

(b)Each of the Selling Stockholders, severally and not jointly, represents and warrants to, and agrees with, the Underwriter and the Company that:

(i)All consents, approvals, authorizations and orders necessary for the execution and delivery by such Selling Stockholder of this Agreement and the Power of Attorney and the Custody Agreement hereinafter referred to, and for the sale and delivery of the Shares to be sold by such Selling Stockholder hereunder, have been obtained; and such Selling Stockholder has full right, power and authority to enter into this Agreement, the Power of Attorney and the Custody Agreement and to sell, assign, transfer and deliver the Shares to be sold by such Selling Stockholder hereunder;

(ii)The Power of Attorney and Custody Agreement executed by such Selling Stockholder have been duly authorized, executed and delivered by such Selling Stockholder and constitute valid and legally binding obligations of such Selling Stockholder enforceable in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles;

(iii)This Agreement has been duly authorized, executed and delivered by such Selling Stockholder;

(iv)The sale of the Shares to be sold by such Selling Stockholder hereunder and the compliance by such Selling Stockholder with all of the provisions of this Agreement, the Power of Attorney and the Custody Agreement (each as defined below) and the consummation of the transactions herein and therein contemplated (A) will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which such Selling Stockholder is a party or by which such Selling Stockholder is bound or to which any of the property or assets of such Selling Stockholder is subject, (B) will not result in any violation of the provisions of the Certificate of Incorporation or By-laws of such Selling Stockholder (if such Selling Stockholder is a corporation), the Certificate of Formation or Operating Agreement or similar organizational agreement of such Selling Stockholder (if such Selling Stockholder is a limited liability company), the Partnership Agreement of such Selling Stockholder (if such Selling Stockholder is a partnership) or the similar organizational documents and agreements of such Selling Stockholder (if such Selling Stockholder is not a natural person, corporation, limited liability company or partnership); or (C) will not result in the violation of any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over such Selling Stockholder or the property of such Selling Stockholder, except in the case of clauses (A) and (C) as would not, individually or in the aggregate, have an adverse effect on the ability of such Selling Stockholder to consummate the transactions contemplated by this Agreement, the Power of Attorney or the Custody Agreement;

(v)Such Selling Stockholder has (or, with respect to each Selling Stockholder formed in the Netherlands or the Netherlands Antilles, one or more of the general partners of such Selling Stockholder have), and immediately prior to each Time of Delivery such Selling Stockholder (or such general partner or general partners) will have, good and valid title to the Shares to be sold by such Selling Stockholder hereunder, free and clear of all liens, encumbrances, equities or claims; and, upon delivery of such Shares and payment therefor pursuant hereto, good and valid title to such Shares, free and clear of all liens, encumbrances, equities or claims, will pass to the Underwriter;

(vi)During the period beginning from the date hereof and continuing to and including the date 60 days after the date of the Prospectus (the initial “Selling Stockholder Lock-Up Period”), such Selling Stockholder will not offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of, except as provided hereunder, any shares of Stock, or any options or warrants to purchase shares of Stock, or any securities of the Company that are substantially similar to the Shares, including but not limited to any securities that are convertible into or exercisable or exchangeable for, or that represent the right to receive, shares of Stock or any such substantially similar security (“Stock Equivalents”); other than bona fide pledges of shares of Stock or such securities in existence as of the date of this Agreement whether now owned or hereafter acquired, owned directly by such Selling Stockholder (including holding as a custodian) or with respect to which such Selling Stockholder has beneficial ownership within the rules and regulations of the Commission, without the prior written consent of the Underwriter. Notwithstanding the foregoing, such Selling Stockholder may transfer shares of Stock and Stock Equivalents (A) as a bona fide gift or gifts, provided that the donee or donees thereof agree to be bound in writing by the restrictions set forth in this Section 1(b)(vi), (B) if such Selling Stockholder is a corporation, limited liability company or limited partnership, to any "affiliate" (within the meaning of such term under Rule 405 as promulgated by the Commission under the Act) of such Selling Stockholder, provided that the transferee executes an agreement stating that the transferee is receiving and holding such shares of Stock or Stock Equivalents so transferred subject to the provisions of this Section 1(b)(vi) and that there shall be no further transfer of shares of Stock or Stock Equivalents of such Selling Stockholder so transferred prior to the expiration of the Selling Stockholder Lock-Up Period (as such may be extended pursuant to this Section 1(b)(vi)), and provided further that any such transfer shall not involve a disposition for value, or (C) with the prior written consent of the Underwriter.

(vii)Such Selling Stockholder has not taken and will not take, directly or indirectly, any action which is designed to or which has constituted or which might reasonably be expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Shares;

(viii)Except as set forth in the Selling Stockholder Questionnaire previously completed and executed by such Selling Stockholder, a copy of which has been provided to the Underwriter, neither such Selling Stockholder nor any of its affiliates directly, or indirectly through one or more intermediaries, controls, or is controlled by, or is under common control with, or has any other association with (as defined in the rules and regulations of the Financial Industry Regulatory Authority, Inc. (“FINRA”)) any member firm of FINRA;

(ix)In order to document the Underwriter’s compliance with the reporting and withholding provisions of the Tax Equity and Fiscal Responsibility Act of 1982 with respect to the transactions herein contemplated, such Selling Stockholder will deliver to you prior to or at the First Time of Delivery (as hereinafter defined) a properly completed and executed United States Treasury Department Form W-9 (or other applicable form or statement specified by Treasury Department regulations in lieu thereof);

(x)Certificates in negotiable form representing all of the Shares to be sold by such Selling Stockholder hereunder have been placed in custody under a Custody Agreement, in the form heretofore furnished to you (the “Custody Agreement”), duly executed and delivered by such Selling Stockholder to American Stock Transfer & Trust Company, as custodian (the “Custodian”), and such Selling Stockholder has duly executed and delivered a Power of Attorney, in the form heretofore furnished to you (the “Power of Attorney”), appointing the persons indicated in Schedule II hereto, and each of them, as such Selling Stockholder’s attorneys-in-fact (the “Attorneys-in-Fact”) with authority to execute and deliver this Agreement on behalf of such Selling Stockholder, to determine the purchase price to be paid by the Underwriter to the Selling Stockholders as provided in Section 2 hereof, to authorize the delivery of the Shares to be sold by such Selling Stockholder hereunder and otherwise to act on behalf of such Selling Stockholder in connection with the transactions contemplated by this Agreement and the Custody Agreement; and

(xi)The Shares represented by the certificates held in custody for such Selling Stockholder under the Custody Agreement are subject to the interests of the Underwriter hereunder; the arrangements made by such Selling Stockholder for such custody, and the appointment by such Selling Stockholder of the Attorneys-in-Fact by the Power of Attorney, are to that extent irrevocable; the obligations of the Selling Stockholders hereunder shall not be terminated by operation of law by the dissolution, winding up or liquidation of such Selling Stockholder, or by the occurrence of any other event; or if any such Selling Stockholder should be dissolved, wound up or liquidated, or if any other such event should occur, before the delivery of the Shares hereunder, certificates representing the Shares shall be delivered by or on behalf of the Selling Stockholders in accordance with the terms and conditions of this Agreement and the Custody Agreement; and actions taken by the Attorneys-in-Fact pursuant to the Powers of Attorney shall be as valid as if such termination, dissolution, winding up, liquidation or other event had not occurred, regardless of whether or not the Custodian, the Attorneys-in-Fact, or any of them, shall have received notice of such termination, dissolution or other event.

2.Subject to the terms and conditions herein set forth, each of the Selling Stockholders agrees, severally and not jointly, to sell to the Underwriter, and the Underwriter agrees to purchase from each of the Selling Stockholders, at a purchase price per share of $25.50 the Firm Shares and in the event and to the extent that the Underwriter shall exercise the election to purchase Optional Shares as provided below, each of the Selling Stockholders agrees, severally and not jointly, to sell to the Underwriter, and the Underwriter agrees to purchase from each of the Selling Stockholders, at the purchase price per share set forth in this Section 2, that portion of the number of Optional Shares as to which such election shall have been exercised (to be adjusted by you so as to eliminate fractional shares).

The Selling Stockholders, as and to the extent indicated in Schedule II hereto, hereby grant, severally and not jointly to the Underwriter the right to purchase at their election up to an aggregate of 900,000 Optional Shares, at the purchase price per share set forth in the paragraph above. Any such election to purchase Optional Shares shall be made in proportion to the number of Optional Shares to be sold by each Selling Stockholder and in accordance with Schedule I hereto. Any such election to purchase Optional Shares may be exercised only by written notice from you to the Attorneys-in-Fact, given within a period of 30 calendar days after the date of this Agreement and setting forth the aggregate number of Optional Shares to be purchased and the date on which such Optional Shares are to be delivered, as determined by you but in no event earlier than the First Time of Delivery (as defined in Section 4 hereof) or, unless you and the Attorneys-in-Fact otherwise agree in writing, earlier than two or later than ten Business Days after the date of such notice.

3.Upon the authorization by the Underwriter of the release of the Firm Shares, the Underwriter proposes to offer the Firm Shares for sale upon the terms and conditions set forth in the Prospectus.

4.(a)The Shares to be purchased by the Underwriter hereunder, in definitive form, and in such authorized denominations and registered in such names as the Underwriter may request upon at least forty-eight hours’ prior notice to the Selling Stockholders shall be delivered by or on behalf of the Selling Stockholders to Goldman, Sachs & Co., through the facilities of the Depository Trust Company (“DTC”), for the account of such Underwriter, against payment by or on behalf of such Underwriter of the purchase price therefor by wire transfer of Federal (same-day) funds to the account specified by the Custodian, as their interests may appear, to Goldman, Sachs & Co. at least forty-eight hours in advance. The time and date of such delivery and payment shall be, with respect to the Firm Shares, 10:00 a.m., New York time, on June 12, 2014 or such other time and date as Goldman, Sachs & Co. and the Selling Stockholders may agree upon in writing, and, with respect to the Optional Shares, 10:00 a.m., New York time, on the date specified by Goldman, Sachs & Co. in the written notice given by the Underwriter of its election to purchase such Optional Shares, or such other time and date as the Underwriter and the Selling Stockholders may agree upon in writing. Such time and date for delivery of the Firm Shares is herein called the “First Time of Delivery”, such time and date for delivery of the Optional Shares, if not the First Time of Delivery, is herein called the “Second Time of Delivery”, and each such time and date for delivery is herein called a “Time of Delivery”.

(b)The documents to be delivered at each Time of Delivery by or on behalf of the parties hereto pursuant to Section 7 hereof, including the cross receipt for the Shares and any additional documents requested by the Underwriter pursuant to Section 7(k) hereof will be delivered at the offices of Vinson & Elkins L.L.P., 1001 Fannin, Suite 2500, Houston, Texas 77002 (the “Closing Location”), and the Shares will be delivered at the Closing Location, all at such Time of Delivery. A meeting will be held at the Closing Location at 4:00 p.m., New York City time, on the Business Day next preceding such Time of Delivery, at which meeting the final drafts of the documents to be delivered pursuant to the preceding sentence will be available for review by the parties hereto. For the purposes of this Agreement, “Business Day” shall mean each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in New York are generally authorized or obligated by law or executive order to close.

5.The Company agrees with the Underwriter:

(a)To prepare the Prospectus in a form approved by you and to file such Prospectus pursuant to Rule 424(b) under the Act not later than the Commission's close of business on the second Business Day following the execution and delivery of this Agreement, or, if applicable, such earlier time as may be required by Rule 430A(a)(3) under the Act; to make no further amendment or any supplement to the Registration Statement or Prospectus prior to the last Time of Delivery which shall be disapproved by you promptly after reasonable notice thereof; to advise you, promptly after it receives notice thereof, of the time when the amendment to the Registration Statement has been filed or becomes effective or any supplement to the Prospectus or any amended Prospectus has been filed and to furnish you with copies thereof; to file promptly all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of the Prospectus and for so long as the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is required in connection with the offering or sale of the Shares; to advise you, promptly after it receives notice thereof, of the issuance by the Commission of any stop order or of any order preventing or suspending the use of any Pricing Prospectus or other prospectus in respect of the Shares, of the suspension of the qualification of the Shares for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose, or of any request by the Commission for the amending or supplementing of the Registration Statement or Prospectus or for additional information; and, in the event of the issuance of any stop order or of any order preventing or suspending the use of any Pricing Prospectus or other prospectus in respect of the Shares or suspending any such qualification, promptly to use its best efforts to obtain the withdrawal of such order;

(b)Promptly from time to time to take such action as you may reasonably request to qualify the Shares for offering and sale under the securities laws of such jurisdictions as you may request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long as may be necessary to complete the distribution of the Shares, provided that in connection therewith the Company shall not be required to qualify as a foreign corporation or to file a general consent to service of process in any jurisdiction;

(c)Prior to 6:00 P.M., New York City time, on the second Business Day next succeeding the date of this Agreement and from time to time, to furnish the Underwriter with written and electronic copies of the Prospectus in New York City in such quantities as you may reasonably request, and, if the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is required at any time prior to the expiration of nine months after the time of issue of the Prospectus in connection with the offering or sale of the Shares and if at such time any events shall have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made when such Prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is delivered, not misleading, or, if for any other reason it shall be necessary during such period to amend or supplement the Prospectus or to file under the Exchange Act any document incorporated by reference in the Prospectus in order to comply with the Act or the Exchange Act, to notify you and upon your request to file such document and to prepare and furnish without charge to the Underwriter and to any dealer in securities as many written and electronic copies as you may from time to time reasonably request of an amended Prospectus or a supplement to the Prospectus which will correct such statement or omission or effect such compliance, and in case the Underwriter is required to deliver a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) in connection with sales of any of the Shares at any time nine months or more after the time of issue of the Prospectus, upon your request but at the expense of the Underwriter, to prepare and deliver to the Underwriter as many written and electronic copies as you may request of an amended or supplemented Prospectus complying with Section 10(a)(3) of the Act;

(d)To make generally available to its securityholders as soon as practicable, but in any event not later than eighteen months after the effective date of each Registration Statement (as defined in Rule 158(c) under the Act), an earnings statement of the Company and its Subsidiaries (which need not be audited) complying with Section 11(a) of the Act and the rules and regulations of the Commission thereunder (including, at the option of the Company, Rule 158);

(e)During the period beginning from the date hereof and continuing to and including the date 45 days after the date of the Prospectus (the initial “Company Lock-Up Period”), not to offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of, except as provided hereunder, any shares of Stock, or any securities of the Company that are substantially similar to the Shares, including but not limited to any securities that are convertible into or exercisable or exchangeable for, or that represent the right to receive, Stock or any such substantially similar securities (other than (i) pursuant to employee stock plans existing on, or upon the conversion, exercise or exchange of convertible, exercisable or exchangeable securities outstanding as of, the date of this Agreement, (ii) private offers of shares of Stock by the Company, or (iii) the issuance of shares of Stock to sellers of assets or of entities, in connection with any acquisitions by the Company or its Subsidiaries, provided that any such issuances pursuant to clause (iii) during the Company Lock-Up Period do not, in the aggregate, exceed 10% of the number of shares of Stock outstanding on the date hereof, and provided further that the recipient of any such shares of Stock executes an agreement acknowledging and agreeing that such recipient shall not sell, transfer or otherwise dispose of, directly or indirectly, any of such shares of Stock so issued prior to the expiration of the Company Lock-Up Period), each without your prior written consent;

(f)To use its best efforts to list the Shares on the New York Stock Exchange (the “Exchange”); and

(g)Upon request of the Underwriter, to furnish, or cause to be furnished, to such Underwriter an electronic version of the Company’s trademarks, servicemarks and corporate logo for use on the website, if any, operated by such Underwriter for the purpose of facilitating the on-line offering of the Shares (the “License”); provided, however, that the License shall be used solely for the purpose described above, is granted without any fee and may not be assigned or transferred.

6.The Company and each of the Selling Stockholders covenant and agree with one another and with the Underwriter that (a) the Company will pay or cause to be paid: (i) the fees, disbursements and expenses of the Selling Stockholders’ and the Company's counsel and accountants in connection with the registration of the Shares under the Act and all other expenses in connection with the preparation, printing and filing of the Registration Statement, any Pricing Prospectus and the Prospectus and amendments and supplements thereto and the mailing and delivering of copies thereof to the Underwriter and dealers; (ii) the cost of printing or producing this Agreement, the Blue Sky Memorandum, closing documents (including any compilations thereof) and any other documents in connection with the offering, purchase, sale and delivery of the Shares; (iii) all expenses in connection with the qualification of the Shares for offering and sale under state securities laws as provided in Section 5(b) hereof, including the fees and disbursements of counsel for the Underwriter in connection with such qualification and in connection with the Blue Sky survey; (iv) all fees and expenses in connection with listing the Shares on the Exchange; (v) the cost of preparing stock certificates; (vi) the cost and charges of any transfer agent or registrar; (vii) any fees and expenses of the Custodian and (viii) all other costs and expenses incident to the performance of the obligations of the Company hereunder which are not otherwise specifically provided for in this Section 6; and (b) such Selling Stockholder will pay or cause to be paid all costs and expenses incident to the performance of such Selling Stockholder's obligations hereunder which are not otherwise specifically provided for in this Section. It is understood, however, that the Company shall bear, and the Selling Stockholders shall not be required to pay or to reimburse the Company for, the cost of any other matters not directly relating to the sale and purchase of the Shares pursuant to this Agreement, and that, except as provided in this Section, and Sections 8 and 11 hereof, the Underwriter will pay all of its own costs and expenses, including the fees of its counsel, stock transfer taxes on resale of any of the Shares by it, and any advertising expenses connected with any offers it may make.

7.The obligations of the Underwriter hereunder, as to the Shares to be delivered at each Time of Delivery, shall be subject, in its discretion, to the condition that all representations and warranties and other statements of the Company and of the Selling Stockholders herein are, at and as of such Time of Delivery, true and correct, the condition that the Company and the Selling Stockholders shall have performed all of its and their obligations hereunder theretofore to be performed, and the following additional conditions:

(a)The Prospectus shall have been filed with the Commission pursuant to Rule 424(b) within the applicable time period prescribed for such filing by the rules and regulations under the Act and in accordance with Section 5(a) hereof; no stop order suspending the effectiveness of the Registration Statement or any part thereof shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission; and all requests for additional information on the part of the Commission shall have been complied with to your reasonable satisfaction;

(b)Vinson & Elkins L.L.P., counsel for the Underwriter, shall have furnished to you such written opinion or opinions dated such Time of Delivery, in such form or forms as are reasonably acceptable to you, and such counsel shall have received such papers and information as they may reasonably request to enable them to pass upon such matters;

(c)Andrews Kurth, LLP, counsel for the Company, shall have furnished to you their written opinion, dated such Time of Delivery, in form and substance satisfactory to you, to the effect that:

(i)The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware, with corporate power and authority to own its properties and conduct its business as described in the Pricing Prospectus and the Prospectus;

(ii)The Company has an authorized capitalizations as set forth in the Prospectus, and all of the issued shares of capital stock of the Company (including the Shares being delivered at such Time of Delivery) have been duly and validly authorized and issued and are fully paid and non-assessable; and the Shares conform in all material respects to the description of the Stock contained in the Pricing Prospectus and the Prospectus;

(iii)The Company has been duly qualified as a foreign corporation for the transaction of business in the State of Texas;

(iv)Each “significant” subsidiary (as defined in Rule 1-02 of Regulation S-X) of the Company formed or incorporated under the laws of the States of Texas and Delaware (the “Applicable Subsidiaries”) is validly existing as a corporation, limited liability company, or limited partnership in good standing under the laws of its jurisdiction of incorporation or formation; and all of the issued and outstanding capital stock, membership interests or partnership interests, as the case may be, of each such Applicable Subsidiary have been duly and validly authorized and issued, are fully paid (to the extent required under the applicable limited liability company agreement or limited partnership agreement of the subsidiary, as applicable) and non-assessable (except as such non-assessability may be affected by Section 18-607 of the Delaware LLC Act, in the case of membership interests, and Section 17-607 of the Delaware LP Act, in the case of any partnership interests in a limited partnership, and Section 17-403 of the Delaware LP Act with respect to general partner interests in a limited partnership), and (except for directors’ qualifying shares) are owned of record directly or indirectly by the Company, and, to the knowledge of such counsel, free and clear of all liens, encumbrances, equities or claims, with such knowledge based solely upon information (A) in respect of which financing statements under the Uniform Commercial Code of the State of Delaware or State of Texas have been filed in the office of the Secretary of State of the State of Delaware or Texas (as applicable for the jurisdiction of incorporation or formation) or (B) otherwise known to such counsel without independent investigation other than inquiry of officers of the Company deemed appropriate by such counsel (except as set forth in the Pricing Prospectus and the Prospectus and other than those created by or arising under Sections 17-403 and 17-607 of the Delaware LP Act or Section 18-607 of the Delaware LLC Act) (such counsel being entitled to rely in respect of the opinion in this clause upon opinions of local counsel and in respect of matters of fact upon certificates of officers of the Company or its subsidiaries, provided that such counsel shall state that they believe that both you and they are justified in relying upon such opinions and certificates);

(v)This Agreement has been duly authorized, executed and delivered by the Company;

(vi)The compliance by the Company with all of the provisions of this Agreement and the consummation of the transactions herein contemplated will not (A) constitute or result in any violation of the provisions of the Certificate of Incorporation or By-laws of the Company, (B) constitute or result in any violation of the Delaware General Corporation Law, the laws of the State of Texas or federal law, (C) result in a breach or violation of the terms or provisions of, or constitute a default under, any indenture, mortgage, deed of trust, loan agreement or other agreement filed as an exhibit to the Registration Statement or the Company’s most recent Annual Report on Form 10-K, or (D) result in a breach or violation of the terms or provisions of any order of any court or governmental agency or body having jurisdiction over the Company or any of its Subsidiaries or any of their properties, which breaches, violations or defaults with respect to clauses (C) and (D) would not, individually or in the aggregate, have a Material Adverse Effect; provided, such counsel expresses no opinion with respect to federal or state securities laws or other antifraud laws;

(vii)No consent, approval, authorization, order, registration or qualification of or with any such court or governmental agency or body is required for the consummation by the Company of the transactions contemplated by this Agreement, except the registration under the Act of the Shares, and such consents, approvals, authorizations, registrations or qualifications as may be required under state securities or blue sky laws in connection with the purchase and distribution of the Shares by the Underwriter;

(viii)The statements set forth in the Pricing Prospectus and the Prospectus under the caption “Description of Common Stock,” insofar as they purport to constitute a summary of the terms of the Stock, under the caption “Material United States Federal Income Tax Considerations for Non-U.S. Holders,” insofar as they purport to constitute a summary of the laws referred to therein, and under the caption “Underwriting,” insofar as they purport to describe the provisions of the laws and documents referred to therein, fairly and accurately summarize such matters in all material respects;

(ix)The Company is not an “investment company,” as such term is defined in the Investment Company Act;

(x)The Registration Statement has been declared effective under the Act; and any required filing of the Prospectus pursuant to Rule 424(b) has been made in the manner and within the time period required by Rule 424(b); and to the knowledge of such counsel, no stop order suspending the effectiveness of the Registration Statement has been issued under the Act and no proceedings for that purpose have been instituted or are pending or, to the knowledge of such counsel, threatened, by the Commission;

(xi)The Registration Statement, the Pricing Prospectus and the Prospectus and any further amendments and supplements thereto made by the Company prior to such Time of Delivery (other than the financial statements and related schedules and other financial data therein, as to which such counsel need express no opinion) at the time it was filed with the Commission appeared on its face to be appropriately responsive in all material respects with the requirements of the Act and the rules and regulations thereunder; although they do not assume any responsibility for the accuracy, completeness or fairness of the statements contained in the Registration Statement, the Pricing Prospectus or the Prospectus, except for those referred to in the opinion in subsection (viii) of this Section 7(c), they have no reason to believe (a) that any part of the Registration Statement or any further amendment thereto made by the Company prior to such Time of Delivery (other than the financial statements and related schedules therein, as to which such counsel need express no opinion), when such part or amendment became effective, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading; (b) that the Pricing Prospectus, as of the Applicable Time, contained any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; or (c) that, as of its date and as of such Time of Delivery, the Pricing Prospectus and the Prospectus or any further amendment or supplement thereto made by the Company prior to such Time of Delivery (other than the financial statements and related schedules and other financial data therein, as to which such counsel need express no opinion) contained or contains an untrue statement of a material fact or omitted or omits to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading; and they do not know of any amendment to the Registration Statement required to be filed or of any contracts or other documents of a character required to be filed as an exhibit to the Registration Statement or required to be described in the Registration Statement or the Pricing Prospectus and the Prospectus which are not filed or described as required.

(d)Counsel for the Selling Stockholders, as indicated in Schedule II hereto, shall have furnished to you their written opinions with respect to the Selling Stockholders dated such Time of Delivery, in forms attached hereto as Annexes A-1, A-2 and A-3.

(e)On the date of the Prospectus at a time prior to the execution of this Agreement, at 9:30 a.m., New York City time, on the effective date of any post‑effective amendment to the Registration Statement filed subsequent to the date of this Agreement and also at each Time of Delivery, KPMG LLP shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you;

(f)(i)Neither the Company nor any of its Subsidiaries shall have sustained since the date of the latest audited financial statements included or incorporated by reference in the Prospectus any loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Prospectus, and (ii) since the respective dates as of which information is given in the Prospectus there shall not have been any change in the capital stock (other than issuances of capital stock in the ordinary course of business pursuant to the Company’s employee benefit plans) or long‑term debt of the Company or any of its Subsidiaries or any change, or any development involving a prospective change, in or affecting the general affairs, management, financial position, stockholders' equity or results of operations of the Company and its Subsidiaries, otherwise than as set forth or contemplated in the Prospectus, the effect of which, in any such case described in clause (i) or (ii), is in the judgment of the Underwriter so material and adverse as to make it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Time of Delivery on the terms and in the manner contemplated in the Prospectus;

(g)On or after the date hereof (i) no downgrading shall have occurred in the rating accorded the Company's debt securities by any "nationally recognized statistical rating organization", as that term is defined by the Commission for purposes of Rule 436(g)(2) under the Act, and (ii) no such organization shall have publicly announced that it has under surveillance or review, with possible negative implications, its rating of any of the Company's debt securities;

(h)On or after the date hereof there shall not have occurred any of the following: (i) a suspension or material limitation in trading in securities generally on the Exchange; (ii) a suspension or material limitation in trading in the Company’s securities on the Exchange; (iii) a general moratorium on commercial banking activities declared by either Federal, New York or Texas State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States; (iv) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (v) the occurrence of any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (iv) or (v) in the judgment of the Underwriter makes it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Time of Delivery on the terms and in the manner contemplated in the Prospectus;

(i)The Shares at the Time of Delivery shall have been duly listed on the Exchange;

(j)The Company shall have obtained and delivered to the Underwriter executed copies of an agreement from each of those persons listed on Schedule III hereto, substantially to the effect set forth in Subsection 1(b)(iv) hereof (a draft of such agreement is attached as Annex I hereto);

(k)The Company shall have complied with the provisions of Section 5(c) hereof with respect to the furnishing of prospectuses on the Business Day next succeeding the date of this Agreement; and

(l)The Company and the Selling Stockholders shall have furnished or caused to be furnished to you at such Time of Delivery certificates of officers of the Company and of the Selling Stockholders, respectively, satisfactory to you as to the accuracy of the representations and warranties of the Company and the Selling Stockholders, respectively, herein at and as of such Time of Delivery, as to the performance by the Company and the Selling Stockholders of all of their respective obligations hereunder to be performed at or prior to such Time of Delivery, and as to such other matters as you may reasonably request, and the Company shall have furnished or caused to be furnished certificates as to the matters set forth in subsections (a) and (f) of this Section.

8.(a)The Company will indemnify and hold harmless the Underwriter, each person, if any, who controls the Underwriter within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act, the agents, employees, officers and directors of the Underwriter and any affiliates of the Underwriter from and against any losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in any Pricing Prospectus, the Registration Statement or the Prospectus, or any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, and will reimburse them for any legal or other expenses reasonably incurred by them in connection with investigating or defending any such action or claim as such expenses are incurred; provided, however, that the Company and the Selling Stockholders shall not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in any Pricing Prospectus, the Registration Statement or the Prospectus or any such amendment or supplement in reliance upon and in conformity with written information furnished to the Company (i) by the Underwriter or (ii) by the Selling Stockholders. The indemnity provided by the Company to the Underwriter pursuant to this Section 8(a) shall in no way alter the indemnification obligations of the Company contained in that certain Third Amended and Restated Stockholders’ Agreement, dated December 20, 2010, by and among the Company and the Selling Stockholders.

(b)Each of the Selling Stockholders, severally and not jointly, will indemnify and hold harmless the Underwriter, each person, if any, who controls the Underwriter within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act, the agents, employees, officers and directors of the Underwriter from and against any losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in any Preliminary Prospectus, the Registration Statement or the Prospectus, or any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in any Preliminary Prospectus, the Registration Statement or the Prospectus or any such amendment or supplement in reliance upon and in conformity with written information furnished to the Company by such Selling Stockholder expressly for use therein; and will reimburse them any legal or other expenses reasonably incurred by them in connection with investigating or defending any such action or claim as such expenses are incurred; provided, however, that such Selling Stockholder shall not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in any Preliminary Prospectus, the Registration Statement or the Prospectus or any such amendment or supplement in reliance upon and in conformity with written information furnished to the Company by the Underwriter; provided, that the liability of any Selling Stockholder pursuant to this Section 8(b) shall not exceed the gross proceeds from the sale of the Shares sold by such Selling Stockholder, including any Optional Shares, pursuant to this Agreement after underwriting commissions and discounts, but before expenses.

(c)The Underwriter will indemnify and hold harmless the Company and each Selling Stockholder and their respective agents, employees, officers and directors and each person, if any, who controls the Company and such Selling Stockholder within the meaning of Section 15 of the Act or Section 20(a) of the Exchange Act, from and against any losses, claims, damages or liabilities to which they or any of them may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in any Pricing Prospectus, the Registration Statement or the Prospectus, or any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in any Pricing Prospectus, the Registration Statement or the Prospectus or any such amendment or supplement in reliance upon and in conformity with written information furnished to the Company by the Underwriter expressly for use therein; and will reimburse the Company and each Selling Stockholder for any legal or other expenses reasonably incurred by the Company or such Selling Stockholder in connection with investigating or defending any such action or claim as such expenses are incurred.

(d)Promptly after receipt by an indemnified party under subsection (a), (b) or (c) above of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify the indemnifying party in writing of the commencement thereof; but the omission so to notify the indemnifying party shall not relieve it from any liability which it may have to any indemnified party otherwise than under such subsection. In case any such action shall be brought against any indemnified party and it shall notify the indemnifying party of the commencement thereof, the indemnifying party shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and, after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party shall not be liable to such indemnified party under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently incurred by such indemnified party, in connection with the defense thereof other than reasonable costs of investigation. 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 (i) includes an unconditional release of the indemnified party from all liability arising out of such action or claim and (ii) 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.

(e)If the indemnification provided for in this Section 8 is unavailable to or insufficient to hold harmless an indemnified party under subsection (a), (b) or (c) above in respect of any losses, claims, damages or liabilities (or actions in respect thereof) referred to therein, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (or actions in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriter on the other from the offering of the Shares, subject to the limitations of liability for the Selling Stockholders set forth in Section 10(b). If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law or if the indemnified party failed to give the notice required under subsection (d) above, then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company and the Selling Stockholders on the one hand and the Underwriter on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities (or actions in respect thereof), as well as any other relevant equitable considerations, subject to the limitations of liability for the Selling Stockholders set forth in Section 10(b). The relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriter on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company and the Selling Stockholders bear to the total underwriting discounts and commissions received by the Underwriter. The relative fault 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 the Company or the Selling Stockholders on the one hand or the Underwriter on the other and the parties' relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Company, each of the Selling Stockholders and the Underwriter agree that it would not be just and equitable if contributions pursuant to this subsection (e) were determined by pro rata allocation or by any other method of allocation which does not take account of the equitable considerations referred to above in this subsection (e). The amount paid or payable by an indemnified party as a result of the losses, claims, damages or liabilities (or actions in respect thereof) referred to above in this subsection (e) shall be deemed to include 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 subsection (e), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter 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 Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriter's obligations in this subsection (e) to contribute are several in proportion to their respective underwriting obligations and not joint.

(f)The obligations of the Company and the Selling Stockholders under this Section 8 shall be in addition to any liability which the Company and the respective Selling Stockholders may otherwise have and shall extend, upon the same terms and conditions, to each person, if any, who controls the Underwriter within the meaning of the Act; and the obligations of the Underwriter under this Section 8 shall be in addition to any liability which the Underwriter may otherwise have and shall extend, upon the same terms and conditions, to each officer and director of the Company and to each person, if any, who controls the Company or any Selling Stockholder within the meaning of the Act.

9.The Underwriter may terminate this Agreement at any time by notice given by you to the Company, if after the execution and delivery of this Agreement and on or prior to the First Time of Delivery or the Time of Delivery related to any Optional Shares, as the case may be (i) any condition specified in Section 7 hereof (other than Section 7(b), regarding delivery of the Underwriter’s counsel opinion) shall not have been satisfied. Any such termination shall be without liability of any party to any other party except as provided in Sections 6 and 8 hereof.

10.The respective indemnities, agreements, representations, warranties and other statements of the Company, the Selling Stockholders and the Underwriter, as set forth in this Agreement or made by or on behalf of them, respectively, pursuant to this Agreement, shall remain in full force and effect, regardless of any investigation (or any statement as to the results thereof) made by or on behalf of the Underwriter or any controlling person of the Underwriter, or the Company, or any of the Selling Stockholders, or any officer or director or controlling person of the Company, or any controlling person of any Selling Stockholder, and shall survive delivery of and payment for the Shares.

11.If this Agreement shall be terminated pursuant to Section 9 hereof, neither the Company nor the Selling Stockholders shall then be under any liability to the Underwriter except as provided in Sections 6 and 8 hereof; but, if for any other reason any Shares are not delivered by or on behalf of the Selling Stockholders as provided herein, the Company will reimburse you for all out‑of‑pocket expenses approved in writing by you, including fees and disbursements of counsel, reasonably incurred by the Underwriter in making preparations for the purchase, sale and delivery of the Shares not so delivered, but the Company and the Selling Stockholders shall then be under no further liability to the Underwriter in respect of the Shares not so delivered except as provided in Sections 6 and 8 hereof.

12.In all dealings hereunder, the parties hereto shall be entitled to act and rely upon any statement, request, notice or agreement made or given by the Underwriter and in all dealings with any Selling Stockholder hereunder, you and the Company shall be entitled to act and rely upon any statement, request, notice or agreement on behalf of such Selling Stockholder made or given by any or all of the Attorneys‑in‑Fact for such Selling Stockholder.

All statements, requests, notices and agreements hereunder shall be in writing, and if to the Underwriter shall be delivered or sent by mail, telex or facsimile transmission to Goldman, Sachs & Co., One New York Plaza, 42nd Floor, New York, New York 10004, Attention: Registration Department; if to any Selling Stockholder shall be delivered or sent by mail, telex or facsimile transmission to counsel for such Selling Stockholder at its address set forth in Schedule II hereto; and if to the Company shall be delivered or sent by mail, telex or facsimile transmission to the address of the Company set forth in the Registration Statement, Attention: Secretary; provided, however, that any notice to the Underwriter pursuant to Section 8(d) hereof shall be delivered or sent by mail, telex or facsimile transmission to the Underwriter at its address set forth in its Underwriter Questionnaire or telex constituting such Questionnaire, which address will be supplied to the Company or the Selling Stockholders by you on request; Any such statements, requests, notices or agreements shall take effect upon receipt thereof.

13.This Agreement shall be binding upon, and inure solely to the benefit of, the Underwriter, the Company and the Selling Stockholders and, to the extent provided in Sections 8 and 10 hereof, the officers and directors of the Company and each person who controls the Company, any Selling Stockholder or the Underwriter, and their respective heirs, executors, administrators, successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement. No purchaser of any of the Shares from the Underwriter shall be deemed a successor or assign by reason merely of such purchase.

14.Time shall be of the essence of this Agreement.

15.In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Underwriter is required to obtain, verify and record information that identifies its respective clients, including the Company and the Selling Stockholders, which information may include the name and address of their respective clients, as well as other information that will allow the Underwriter to properly identify its respective clients.

16.This Agreement shall be governed by and construed in accordance with the laws of the State of New York.

17.This Agreement may be executed by any one or more of the parties hereto in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same instrument.

18.Notwithstanding anything herein to the contrary, the Company and the Selling Stockholders are authorized to disclose to any persons the U.S. federal and state income tax treatment and tax structure of the potential transaction and all materials of any kind (including tax opinions and other tax analyses) provided to the Company and the Selling Stockholders relating to that treatment and structure, without the Underwriter imposing any limitation of any kind. However, any information relating to the tax treatment and tax structure shall remain confidential (and the foregoing sentence shall not apply) to the extent necessary to enable any person to comply with securities laws. For this purpose, “tax structure” is limited to any facts that may be relevant to that treatment.

If the foregoing is in accordance with your understanding, please sign and return to us counterparts hereof, and upon the acceptance hereof by you, this letter and such acceptance hereof shall constitute a binding agreement among the Underwriter, the Company and each of the Selling Stockholders.


SCHEDULE I

Underwriter	Total Number of Shares to be Purchased	Number of Optional Shares to be Purchased if Maximum Option Exercise
Goldman, Sachs & Co............................................................................	6,000,000	900,000


	Total Number of Firm Shares to be Sold	Number of Optional Shares to be Sold if Maximum Option Exercised
The Selling Stockholder(s):
DLJ Merchant Banking Partners III, L.P.	4,202,831	630,425
DLJ Offshore Partners III, L.P.	293,873	44,081
DLJ Offshore Partners III-1, C.V.	75,844	11,377
DLJ Offshore Partners III-2, C.V.	54,029	8,104
DLJ MB PartnersIII GmbH & Co. KG	35,847	5,377
Millennium Partners II, L.P.	7,149	1,072
MBP III Plan Investors, L.P.	790,408	118,561
DLJMB Funding III, Inc.	43,928	6,589
DLJ ESC II, L.P.	496,091	74,414
Total	6,000,000	900,000