SECURITIES PURCHASE AGREEMENT by and among

Exhibit 10(s)

EXECUTION COPY

SECURITIES PURCHASE AGREEMENT

by and among

CMS INTERNATIONAL VENTURES, L.L.C.,

CMS CAPITAL, L.L.C.,

CMS GAS ARGENTINA COMPANY

and

CMS ENTERPRISES COMPANY

and

PACIFIC ENERGY LLC.

together with

EMPRESA NACIONAL DE ELECTRICIDAD S.A.

Dated as of July 11, 2007

EXHIBITS

SCHEDULES TO THE DISCLOSURE LETTERS APPENDED AS EXHIBITS

SCHEDULES TO THE DISCLOSURE LETTERS APPENDED AS EXHIBITS

ADDITIONAL SCHEDULES TO STOCK PURCHASE AGREEMENT

SECURITIES PURCHASE AGREEMENT

     This SECURITIES PURCHASE AGREEMENT (hereinafter also referred to as this “ Agreement ”), dated as of July 11, 2007 (the “ Effective Date ”), is entered into by and among (i) CMS International Ventures, L.L.C., a limited liability company organized and existing under the laws of the State of Michigan (“ Seller ”), (ii) CMS Capital, L.L.C., a limited liability company organized and existing under the laws of the State of Michigan (“ CMS-Capital ”), CMS Gas Argentina Company, a company organized and existing under the laws of the Cayman Islands (“ CMS-Cayman ”), and, CMS Enterprises Company, a corporation organized and existing under the laws of the State of Michigan (“ CMS-Enterprises ”; each of the Seller, CMS-Capital, CMS-Cayman, and CMS-Enterprises is also referred to herein as a “ Note Holder ” and, collectively, the “ Note Holders ”), (iii) Pacific Energy LLC., a limited liability company organized and existing under the laws of the State of Delaware (“ Purchaser ”) and (iv) Empresa Nacional de Electricidad S.A., a company organized and existing under the laws of Chile (“ Parent ”), solely for purposes of Section 8.2 and the beneficial owner of all of the shares of Purchaser. Each of Purchaser, Seller and the Note Holders are sometimes referred to individually herein as a “ Party ” and collectively as the “ Parties ”. Certain other terms are defined throughout this Agreement and in Section 9.2 .

WITNESSETH:

     WHEREAS Seller owns all the issued and outstanding Equity Interests of (i) CMS Gas Transmission del Sur Company, a Cayman Islands company (“ CMS-Gas ”) and (ii) CMS Generation Investment Company V, a Cayman Islands company (“ CMS-Generation ”; each of CMS-Gas and CMS-Generation are sometimes referred to individually herein as a “ Company ” and collectively as the “ Companies ”, and all the issued and outstanding Equity Interests of the Companies are collectively referred to as the “ Shares ”);

     WHEREAS CMS-Gas owns (i) 13.94% of the Equity Interests in Inversiones GasAtacama Holding Limitada, a Chilean limited company (the “ Governing Company ”); and (ii) 99% of the issued and outstanding Equity Interests of Compañía de Inversiones CMS Energy Chile Limitada, a Chilean limited liability entity (“ CMS-Inversiones ”);

     WHEREAS CMS-Generation currently owns 1% of the Equity Interest of CMS Inversiones;

     WHEREAS CMS-Inversiones owns (i) 36.06% of the Equity Interests in the Governing Company, (ii) 0.001% of the Equity Interests in GasAtacama S.A., a Chilean closed corporation (the “ Holding Company ”) and (iii) 0.05% of the Equity Interests in each of the following Chilean closed corporations: GasAtacama Generación S.A., Gasoducto Atacama Chile S.A., and Gasoducto Atacama Argentina S.A.;

     WHEREAS Holding Company owns (i) 99.9% of the Equity Interests in GasAtacama Generación S.A., (ii) 99.9% of the Equity Interests in Gasoducto Atacama Chile S.A., and (iii) 99.9% of the Equity Interests in Gasoducto Atacama Argentina S.A.;

     WHEREAS Governing Company owns 99.9% of the Equity Interests in Atacama Finance Co.;

     WHEREAS Holding Company owns 0.1% of the Equity Interests in Atacama Finance Co.; and

     WHEREAS on March 15, 2006, Atacama Finance Co., a corporation incorporated and existing under the laws of the Cayman Islands, issued as promissor the following promissory notes (i) to Seller for fifty-four million sixty-five thousand five hundred ninety-four dollars and forty-nine cents (U.S.$54,065,594.49) (the “ Seller Note ”), (ii) to CMS-Capital for eighty-seven million three hundred seventy-two thousand six hundred seventy-six dollars and twenty-three cents (U.S.$87,372,676.23) (the “ CMS-Capital Note ”), (iii) to CMS-Cayman for seven million seven hundred thirty-four thousand forty dollars and twenty-four cents (U.S.$7,734,040.24) (the “ CMS-Cayman Note ”), and (iv) to CMS Enterprises Investment Company I, which subsequently transferred and assigned to CMS-Enterprises a note for twenty-six million ninety-nine thousand eight hundred sixty-eight dollars (U.S.$26,099,868.00) (the “ CMS-Enterprises Note ”; each of the Seller Note, the CMS-Capital Note, the CMS-Cayman Note and the CMS-Enterprises Note is individually referred to as a “ Note ” and, collectively, as the “ Notes ”);

     NOW, THEREFORE, in consideration of the mutual promises, covenants, representations and warranties made in this Agreement and of the mutual benefits to be derived therefrom, the Parties hereby agree as follows:

ARTICLE I

SALE AND PURCHASE OF SHARES AND NOTES

          1.1 Sale and Purchase of Shares . Upon the terms and subject to the conditions of this Agreement, and simultaneously with the payment of the Purchase Price in accordance with Section 1.6 of this Agreement, at the Closing, Purchaser shall purchase from Seller, and Seller shall sell to Purchaser, good and valid title, free and clear of any Liens except those created by Purchaser arising out of ownership of the Shares by Purchaser, all of the Shares (the “ Shares Transaction ”).

          1.2 [Intentionally Omitted.]

          1.3 Sale and Purchase of Notes . Upon the terms and subject to the conditions of this Agreement, and simultaneously with the payment of the Purchase Price in accordance with Section 1.6 of this Agreement, at the Closing (a) Purchaser shall purchase from Seller, and Seller shall sell to Purchaser, the Seller Note (inclusive of all accrued and unpaid interest prior to the Closing Date); (b) Purchaser shall purchase from CMS-Capital, and CMS-Capital shall sell to Purchaser, the CMS-Capital Note (inclusive of all accrued and unpaid interest prior to the Closing Date); (c) Purchaser shall purchase from CMS-Cayman, and CMS-Cayman shall sell to Purchaser, the CMS-Cayman Note (inclusive of all accrued and unpaid interest prior to the Closing Date); and (d) Purchaser shall purchase from CMS-Enterprises (inclusive of all accrued and unpaid interest prior to the Closing Date), and CMS-Enterprises shall sell to Purchaser, the CMS-Enterprises Note (inclusive of all accrued and unpaid interest prior to the Closing Date).

The transactions with respect to the Notes contemplated by this Section 1.3 are collectively referred to as the “ Notes Transaction ”, and together with the Shares Transaction, the “ Transactions ”).

          1.4 Purchase Price . The consideration to be paid by Purchaser in respect of the Shares and the Notes shall be an aggregate amount in cash equal to Eighty Million dollars (US$80,000,000) in the legal currency of the United States of America (the “ Purchase Price ”).

          1.5 Closing . The closing of the Transactions (the “ Closing ”) shall take place in New York, New York, at 10:00 a.m., local time, on the second Business Day immediately following the date on which the last of the conditions contained in Article VI are fulfilled or waived (except for those conditions which by their nature can only be fulfilled at the Closing, but subject to the fulfillment or waiver of such conditions), but in any event not before August 1, 2007 or later than August 28, 2007, or at such other place, time and date (the “ Closing Date ”) as the Parties may agree.

          1.6 Closing Deliveries . At the Closing:

               (a) Purchaser shall pay, or cause to be paid, to Seller (or any Affiliate designated by Seller prior to the Closing) an amount in cash equal to the Purchase Price (after application of the Deposit previously delivered to Seller pursuant to Section 1.7 ) for the Shares and Notes so delivered by Seller and the Note Holders, as applicable, by wire transfer of immediately available funds to the bank account or accounts designated by Seller prior to the Closing.

               (b) Seller shall deliver to Purchaser (i) one or more instruments of transfer in respect of the Shares, duly executed in proper form for transfer and (ii) evidence of approval by the directors of each Company for entry in the “Register of Members” of each Company approving the transfer of the Shares to the respective transferee designated by Purchaser.

               (c) Each Note Holder, as applicable, shall deliver to Purchaser its respective Note, duly indorsed “Without Recourse” (or accompanied by an instrument duly indorsed “Without Recourse”) in blank for transfer.

               (d) Seller shall deliver to Purchaser all of the Companies and CMS-Inversiones accounting, tax, corporate and commercial books and records that are located in Seller’s headquarters offices in Michigan.

               (e) Empresa Nacional de Electricidad S.A. and CMS-Enterprises shall execute and deliver to each other an instrument pursuant to which both parties shall terminate the Consortium Agreement with full releases by each party of any subsequent claims against the other thereunder.

               (f) Each Party shall deliver the certificates, agreements, instruments and other documents required to be delivered by it pursuant to Article VI .

          1.7 Purchase Agreement Fee . On July 3, 2007, the Parent wire transferred in favor of CMS Enterprises Company Fifteen Million Dollars (US$15,000,000) (the “Deposit”) in cash (the aggregate of such amount, plus any interest deemed earned thereon at the Specified Rate from (and including) July 3, 2007 to (but excluding) the date of early termination of the Agreement (except pursuant to Section 7.1(f)), being referred to as the “ Purchase Agreement Fee ”).. The Purchase Agreement Fee will be deemed to earn interest at the Specified Rate. Notwithstanding any provision to the contrary contained herein, the Purchase Agreement Fee shall be nonrefundable by Seller; provided , however , the Purchase Agreement Fee shall be refundable in the event that this Agreement is terminated in accordance with Article VII, except Section 7.1(f) , in which event Seller shall pay to the Parent, no later than five (5) Business Days following the effective date of such termination, an amount equal to the Purchase Agreement Fee received by it pursuant to this Section 1.7 by wire transfer of immediately available funds in United States dollars to the bank account or accounts designated by the Parent. The Deposit shall be credited against the Purchase Price payable at Closing to Seller or any Affiliate designated by Seller. If this Agreement is terminated (other than pursuant to Section 7.1(a) , the Purchase Agreement Fee shall be credited against the Damages, if any, owed by Purchaser to Seller arising out of breach of this Agreement by Purchaser. The Purchase Agreement Fee shall not be deemed to be a liquidated damages payment for any breach by Purchaser of this Agreement. If Seller fails to refund the Purchase Agreement Fee within five (5) Business Days of Seller becoming obligated hereunder to make such a refund, the amount thereof shall bear default interest at a rate equal to LIBOR plus two per cent (2%) per annum.

ARTICLE II

REPRESENTATIONS AND WARRANTIES OF SELLER AND NOTE HOLDERS

          2.1 Representations and Warranties of Seller . Except as otherwise disclosed in the Seller Disclosure Letter attached hereto as Exhibit A (the “ Seller Disclosure Letter ”), Seller represents and warrants, as to itself only, and in connection with the Shares Transaction only, to Purchaser, as follows in this Section 2.1 :

               2.1.1 Organization and Qualification . Seller is a limited liability company duly formed and validly existing under the laws of the State of Michigan, and has full power and authority to own, lease and operate its assets and properties and to conduct its business as presently conducted, except where the failure to have such power and authority would not reasonably be expected to have, individually or in the aggregate, a Seller Material Adverse Effect.

               2.1.2 Title to Shares . As of the Closing Date, Seller will be the lawful record and beneficial owner of the Shares set forth opposite its name in Schedule 2.1.2 of the Seller Disclosure Letter, free and clear of any and all Liens, except for Liens created by this Agreement. The Shares constitute all of the issued and outstanding Equity Interests in the Companies. The transfer of the Shares to Purchaser in the manner contemplated under Article I , simultaneously with the payment by Purchaser of the Purchase Price to Seller, shall transfer to Purchaser valid beneficial and legal title to the Shares. There are no outstanding options, warrants or other rights of any kind to acquire from Seller or any of its Affiliates any Shares or securities convertible into or exchangeable for, or which otherwise confer on the holder thereof

any right to acquire from Seller any Shares, nor is Seller committed to issue any such option, warrant, right or security.

               2.1.3 Authority; Non-Contravention; Approvals .

               (a)  Authority . As of the Effective Date Seller has full power and authority to enter into this Agreement and, to consummate the transactions to be effected by Seller as contemplated hereby. As of the Effective Date the execution, delivery and performance by Seller of this Agreement and the consummation by Seller of the transactions to be effected by Seller as contemplated hereby shall have been duly and validly authorized by all requisite action on the part of Seller, and no other proceedings or approvals on the part of Seller shall thereafter be necessary to authorize this Agreement or to consummate the transactions to be effected by Seller as contemplated hereby. As of the Effective Date this Agreement shall have been duly executed and delivered by Seller and, assuming the due authorization, execution and delivery hereof by Purchaser, shall thereafter constitute the legal, valid and binding obligation of Seller, enforceable against Seller in accordance with its terms, except as limited by applicable Law affecting the enforcement of creditors’ rights generally or by general equitable principles.

               (b)  Non-Contravention . Except for matters arising with respect to the regulatory or corporate status of Purchaser, the execution and delivery of this Agreement by Seller do not, and the consummation of the transactions contemplated hereby will not, result in any violation or breach of or default (with or without notice or lapse of time or both) under, or give rise to a right of termination, cancellation or acceleration of any obligation under (any such violation, breach, default, right of termination, cancellation or acceleration is referred to herein as a “ Violation ”), or result in the creation of any Lien upon any of the properties or assets of Seller pursuant to any provision of (i) the Organizational Documents of Seller; (ii) any lease, mortgage, indenture, note, bond, deed of trust, or other written instrument or agreement of any kind to which it or any of its Affiliates is a party or by which it or any of its Affiliates may be bound; or (iii) any Law, Permit or Governmental Order applicable to it or any of its Affiliates, other than in the case of clauses (i), (ii) and (iii) any such Violation or Lien which would not reasonably be expected to have, individually or in the aggregate, a Seller Material Adverse Effect.

               (c)  Approvals . Except for the filings or approvals as may be required due to the regulatory or corporate status of Purchaser, no Consent of any Person is required to be made or obtained by Seller in connection with the execution and delivery of this Agreement or the consummation by Seller of the transactions to be effected by Seller as contemplated hereby, except those which the failure to make or obtain would not reasonably be expected to have, individually or in the aggregate, a Seller Material Adverse Effect. Schedule 2.1.3(d) sets forth other material consents, approvals, filings and notices that may be necessary, advisable or appropriate in connection with the transactions contemplated by this Agreement.

               2.1.4 Organization and Qualification of Companies and CMS-Inversiones; Capitalization .

               (a) Each Company and CMS-Inversiones has been duly formed, is validly existing and is in good standing (to the extent such concepts are recognized under

applicable Law) under the laws of the jurisdiction of its formation, with full corporate power and authority to own or lease and to operate its properties and to conduct its business as presently conducted and is duly qualified to do business in all jurisdictions in which such qualification is necessary under applicable Law as a result of the conduct of its business or the operation of its properties.

               (b) The authorized capital stock of the Companies consists of (i) for CMS-Gas, 50,000 ordinary shares, $1.00 par value, of which 100 shares are issued and outstanding, and (ii) for CMS-Generation, 50,000 ordinary shares, $1.00 par value, of which 100 shares are issued and outstanding. CMS-Inversiones was initially formed with subscribed capital of CLP 187,650,000,000.

               (c) Except as provided for in the Organizational Documents of the Companies and of CMS-Inversiones, there are no subscriptions, options, warrants, calls, conversion, exchange, purchase right or other written contracts, rights, agreements or commitments of any kind obligating, directly or indirectly, the Companies or CMS-Inversiones to issue, transfer, sell or otherwise dispose of, or cause to be issued, transferred, sold or otherwise disposed of, any Equity Interests of the Companies or CMS-Inversiones or any securities convertible into or exchangeable for any such Equity Interests.

               (d) None of the Companies or CMS-Inversiones has any material third party debt as of the date of this Agreement. As of the Closing Date, the only assets of the Companies and CMS-Inversiones will be the Equity Interests set forth on Schedule 3.1.1.

               2.1.5 Brokers and Finders . Neither Seller nor any of its Affiliates has entered into any written agreement or arrangement entitling any agent, broker, investment banker, financial advisor or other firm or Person to any broker’s or finder’s fee or any other commission or similar fee payable by Seller, its Affiliates or the Companies in connection with any of the transactions contemplated by this Agreement, except J.P. Morgan Securities Inc.

               2.1.6 Financial Distress of Companies Subsidiaries . The business, operations and financial condition of the Companies Subsidiaries are subject to considerable distress, and the bankruptcy of one or more of the Companies Subsidiaries is a material probability or likelihood. To the extent that Seller or its Affiliates reasonably believes upon the advice of counsel such action to be required from a legal standpoint, a bankruptcy filing for one or more Companies Subsidiaries shall not constitute a breach of this Agreement or an event that constitutes a failure of condition to Closing or that gives rise to a right to terminate this Agreement. For the avoidance of doubt, under no circumstances shall Seller be required or expected to provide any equity or debt financing to any of the Operating Companies.

               2.1.7 No Other Representations and Warranties.

               EXCEPT FOR THE REPRESENTATIONS AND WARRANTIES CONTAINED IN THIS ARTICLE II (INCLUDING THE DISCLOSURE SCHEDULES), THE SELLER MAKES NO EXPRESS OR IMPLIED REPRESENTATION OR WARRANTY, AND THE SELLER HEREBY DISCLAIMS ANY SUCH REPRESENTATION OR WARRANTY WITH RESPECT TO THE EXECUTION AND DELIVERY OF THIS AGREEMENT AND

THE CONSUMMATION OF THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT.

          2.2 Representations and Warranties of the Note Holders . Except as otherwise disclosed in the Note Holders Disclosure Letter attached hereto as Exhibit B (the “ Note Holders Disclosure Letter ”), each Note Holder severally and not jointly represents and warrants, as to itself only, and in connection with the Notes Transaction only, to Purchaser, as follows in this Section 2.2 :

               2.2.1 Organization and Qualification . Each Note Holder is a legal entity duly formed and validly existing under the laws of the jurisdictions of its formation, and has the power and authority to own, lease and operate its assets and properties and to conduct its business as presently conducted, except where the failure to have such power and authority would not reasonably be expected to have, individually or in the aggregate, a Seller Material Adverse Effect.

               2.2.2 Title to Notes . Each Note Holder is the lawful record and beneficial owner of each Note set forth opposite its name in Schedule 2.2.2 of the Note Holders Disclosure Letter, free and clear of any and all Liens. A true and correct copy of each Note, as amended from time to time through the date of this Agreement, has been made available to Purchaser prior to the date hereof. From December 31, 2006 through the date of this Agreement, none of the Note Holders have consented to any waiver of any of its rights under the applicable Notes.

               2.2.3 Authority; Non-Contravention; Approvals .

               (a)  Authority . As of the Effective Date, each Note Holder has full power and authority to enter into this Agreement and to consummate the transactions to be effected by the Note Holder as contemplated hereby. As of the Effective Date, the execution, delivery and performance by each Note Holder of this Agreement and the consummation by each Note Holder of the transactions to be effected by the Note Holder as contemplated hereby shall have been duly and validly authorized by all requisite action on the part of each Note Holder, and no other proceedings or approvals on the part of a Note Holder shall thereafter be necessary to authorize this Agreement or to consummate the transactions to be effected by the Note Holder as contemplated hereby. As of the Effective Date, this Agreement shall have been duly executed and delivered by the Note Holders and, assuming the due authorization, execution and delivery hereof by Purchaser, shall thereafter constitute the legal, valid and binding obligation of each Note Holder, enforceable against the Note Holders in accordance with its terms, except as limited by applicable Law affecting the enforcement of creditors’ rights generally or by general equitable principles.

               (b)  Non-Contravention . Except for matters arising with respect to the regulatory or corporate status of Purchaser, the execution and delivery of this Agreement by the Note Holders do not, and the consummation of the transactions contemplated hereby will not, result in any Violation, or result in the creation of any Lien upon any of the properties or assets of the Note Holders pursuant to any provision of (i) the Organizational Documents of the Note Holders; (ii) any lease, mortgage, indenture, note, bond, deed of trust, or other written instrument

or agreement of any kind to which the Note Holders are a party or by which they may be bound; or (iii) any Law, Permit or Governmental Order applicable to it, subject to obtaining the Note Holders Required Approvals; other than in the case of clauses (i), (ii) and (iii) any such Violation or Lien which would not reasonably be expected to have, individually or in the aggregate, a Seller Material Adverse Effect.

               (c)  Approvals . Except for the filings or approvals as may be required due to the regulatory or corporate status of Purchaser, no Consent of any Person is required to be made or obtained by any Note Holder in connection with the execution and delivery of this Agreement or the consummation by the Note Holders of the transactions to be effected by Note Holders as contemplated hereby, except those which the failure to make or obtain would not reasonably be expected to have, individually or in the aggregate, a Seller Material Adverse Effect.

               2.2.4 Brokers and Finders . Neither the Note Holders nor any of their Affiliates have entered into any written agreement or arrangement entitling any agent, broker, investment banker, financial advisor or other firm or Person to any broker’s or finder’s fee or any other commission or similar fee payable by any of the Note Holders or their Affiliates in connection with any of the transactions contemplated by this Agreement, except J.P. Morgan Securities Inc.

               2.2.5 Financial Distress of Companies Subsidiaries . Purchaser acknowledges that the business, operations and financial condition of the Companies Subsidiaries are subject to considerable distress, and the bankruptcy of one or more of the Companies Subsidiaries is a material probability or likelihood. To the extent that Seller or its Affiliates reasonably believes upon the advice of counsel such action to be required from a legal standpoint, a bankruptcy filing for one or more Companies Subsidiaries shall not constitute a breach of this Agreement or an event that constitutes a failure of a condition to Closing or that gives rise to a right to terminate this Agreement. For the avoidance of doubt, under no circumstances shall Seller be required or expected to provide any equity or debt financing to any of the Operating Companies.

               2.2.6 No Other Representations and Warranties .

               EXCEPT FOR THE REPRESENTATIONS AND WARRANTIES CONTAINED IN THIS ARTICLE II (INCLUDING THE DISCLOSURE SCHEDULES), NONE OF THE NOTE HOLDERS MAKES ANY EXPRESS OR IMPLIED REPRESENTATION OR WARRANTY, AND EACH NOTE HOLDER HEREBY DISCLAIMS ANY SUCH REPRESENTATION OR WARRANTY WITH RESPECT TO THE EXECUTION AND DELIVERY OF THIS AGREEMENT AND THE CONSUMMATION OF THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT.

ARTICLE III

REPRESENTATIONS AND WARRANTIES OF SELLER WITH RESPECT
TO THE COMPANIES SUBSIDIARIES

     Except as disclosed in the Seller Disclosure Letter, Seller represents and warrants to Purchaser, as follows in this Article III ( provided that each representation and warranty made by Seller in this Article III is made solely to the Knowledge of Seller).:

          3.1 Capitalization and Title .

               3.1.1 Description . Set forth on Schedule 3.1.1 of the Seller Disclosure Letter for each of the Companies Subsidiaries and CMS-Inversiones is (i) its jurisdiction of formation; (ii) its authorized Equity Interests; (iii) the number of its issued and outstanding Equity Interests; and (iv) the names of the owners of its issued and outstanding Equity Interests.

               3.1.2 No Consents to Liens . From December 31, 2006 through the date of this Agreement, none of Seller, the Governing Company or the Holding Company has consented to the creation of any Liens on the Equity Interests of any of the Companies Subsidiaries.

          3.2 Financial Statements . The audited balance sheet as at December 31, 2006 and the related audited statements of income and of cash flows for the year then ended for each Companies Subsidiary (individually, a “ Company Subsidiary Financial Statement ” and, collectively, the “ Companies Subsidiaries Financial Statements ”) have been provided to Purchaser prior to the date of this Agreement. As of the respective dates thereof, each Companies Subsidiary Financial Statement fairly presents in all material respects the financial position of the respective Companies Subsidiary as of December 31, 2006, and the results of such Companies Subsidiary’s operations and cash flows for the period indicated (except for normal and recurring year-end adjustments) in conformity with Chilean GAAP in accordance with the terms thereof); provided that no representation is made by Seller with respect to whether any write-off or other adjustment of asset values would have been appropriate as of any such dates. From December 31, 2006 through the date of this Agreement, Seller has not approved the incurrence of any third party debt by any of the Companies Subsidiaries, nor is Seller aware of any such incurrence during such period.

          3.3 Tax Matters . Except as set forth in Schedule 3.3 of the Seller Disclosure Letter, each of the Companies Subsidiaries has, or, in each case, a Person acting on its behalf has as of the date of this Agreement filed with the appropriate Governmental Entity all material Tax Returns required to have been filed by it. No material audits or other proceedings are pending, as of the date hereof, with regard to any material Taxes or Tax Returns.

          3.4 Compliance with Laws . Except as set forth in Schedule 3.4 of the Seller Disclosure Letter, as of the date of this Agreement none of the Company, any Companies Subsidiary or CMS-Inversiones has received written notice of or has been charged with any violation of, nor is it under investigation with respect to any violation of, any applicable Law (including any applicable foreign corrupt practices Law) or applicable Governmental Order,

except in each case for violations which would not reasonably be expected to have, individually or in the aggregate, a Companies Material Adverse Effect.

          3.5 Certain Contracts . Purchaser has been provided with a true and correct copy of each contract identified in Schedule 3.5 of the Seller Disclosure Letter. As of the date of this Agreement, no party to the contracts identified in Schedule 3.5 of the Seller Disclosure Letter is in breach or default thereunder, except in each case for any breach or default that would not reasonably be expected to have, individually or in the aggregate, a Companies Material Adverse Effect.

          3.6 Operating Company Notes. Purchaser has been provided with a true and correct copy of each promissory note issued by any Operating Company in favor of Atacama Finance Co. as in effect as of the date hereof (the “ Operating Company Notes ”). From December 31, 2006 through the date of this Agreement, the Seller has not consented to any waiver of any rights of Atacama Finance Co. under any of the Operating Company Notes nor is Seller aware of any such waiver during such period.

          3.7 Financial Distress of Companies Subsidiaries . THE BUSINESS, OPERATIONS AND FINANCIAL CONDITION OF THE COMPANIES SUBSIDIARIES ARE SUBJECT TO CONSIDERABLE DISTRESS, AND THE BANKRUPTCY OF ONE OR MORE OF THE COMPANIES SUBSIDIARIES IS A MATERIAL PROBABILITY OR LIKELIHOOD. TO THE EXTENT THAT SELLER OR ITS AFFILIATES REASONABLY BELIEVES UPON THE ADVICE OF COUNSEL SUCH ACTION TO BE REQUIRED FROM A LEGAL STANDPOINT, A BANKRUPTCY FILING FOR ONE OR MORE COMPANIES SUBSIDIARIES SHALL NOT CONSTITUTE A BREACH OF THIS AGREEMENT OR AN EVENT THAT CONSTITUTES A FAILURE OF CONDITION TO CLOSING OR THAT GIVES RISE TO A RIGHT TO TERMINATE THIS AGREEMENT. FOR THE AVOIDANCE OF DOUBT, UNDER NO CIRCUMSTANCES SHALL SELLER BE REQUIRED OR EXPECTED TO PROVIDE ANY EQUITY OR DEBT FINANCING TO ANY OF THE OPERATING COMPANIES.

          3.8 No Other Representations and Warranties. EXCEPT FOR THE REPRESENTATIONS AND WARRANTIES CONTAINED IN THIS ARTICLE III (INCLUDING THE DISCLOSURE SCHEDULES), THE SELLER MAKES NO EXPRESS OR IMPLIED REPRESENTATION OR WARRANTY WITH RESPECT TO THE COMPANIES SUBSIDIARIES, AND THE SELLER HEREBY DISCLAIMS ANY SUCH REPRESENTATION OR WARRANTY WITH RESPECT TO THE COMPANIES SUBSIDIARIES.

ARTICLE IV

REPRESENTATIONS AND WARRANTIES OF PURCHASER

     Purchaser represents and warrants to Seller and to the Note Holders as follows in this Article IV :

          4.1 Organization and Qualification . Purchaser is a limited liability company, duly formed, validly existing and in good standing under the laws of the State of Delaware. Purchaser has full power and authority to own, lease and operate its assets and properties and to conduct its business as presently conducted. Purchaser is duly qualified to do business and in good standing as a foreign limited liability company in all jurisdictions in which such qualification is necessary under applicable Law as a result of the conduct of its business or the ownership of its properties, except for those jurisdictions where failure to be so qualified or in good standing would not reasonably be expected to have, individually or in the aggregate, a Purchaser Material Adverse Effect.

          4.2 Authority; Non-Contravention; Approvals .

               (a)  Authority . Purchaser has full power and authority to enter into this Agreement and to consummate the transactions contemplated hereby. The execution, delivery and performance by Purchaser of this Agreement and the consummation by Purchaser of the transactions contemplated hereby have been duly and validly authorized by all requisite action on the part of Purchaser, and no other proceedings or approvals on the part of Purchaser are necessary to authorize this Agreement or to consummate the transactions contemplated hereby. This Agreement has been duly executed and delivered by Purchaser and, assuming the due authorization, execution and delivery hereof by each other Party, constitutes the legal, valid and binding obligation of Purchaser, enforceable against Purchaser in accordance with its terms, except as limited by applicable Law affecting the enforcement of creditors’ rights generally or by general equitable principles.

               (b)  Non-Contravention . The execution and delivery of this Agreement by Purchaser do not, and the consummation of the transactions contemplated hereby will not, result in any Violation or result in the creation of any Lien upon any of the respective properties or assets of Purchaser pursuant to any provision of (i) the Organizational Documents of Purchaser, as the case may be; (ii) any lease, mortgage, indenture, note, bond, deed of trust, or other written instrument or agreement of any kind to which Purchaser is a party or by which Purchaser may be bound; or (iii) any Law, Permit or governmental order applicable to Purchaser; other than in the case of clauses (i), (ii) and (iii) for any such Violation or Lien that would not reasonably be expected to have, individually or in the aggregate, a Purchaser Material Adverse Effect.

               (c)  Approvals . Except for the filings or approvals as may be required due to the regulatory or corporate status of Seller or any Company, no Consent of any Governmental Entity is required to be made or obtained by Purchaser in connection with the execution and delivery of this Agreement or the consummation by Purchaser of the transactions

contemplated hereby, except those which the failure to make or obtain would not reasonably be expected to have, individually or in the aggregate, a Purchaser Material Adverse Effect.

          4.3 Financing . Purchaser has, and will have at the Closing, available cash and/or credit capacity, either in its accounts, through binding and enforceable credit arrangements or borrowing facilities or otherwise, (i) to pay the Purchase Price at the Closing, (ii) to pay all fees and expenses required to be paid by Purchaser in connection with the transactions contemplated by this Agreement, and (iii) to perform all of its other obligations hereunder.

          4.4 Investment Intention; Sufficient Investment Experience; Independent Investigation; Financial Distress of Companies Subsidiaries .

               (a) Purchaser understands that the purchase of the Shares and Notes pursuant to the terms of this Agreement involves substantial risk. Purchaser has such knowledge and experience in financial and business matters that it is capable of evaluating the Companies, the Companies Subsidiaries and the Notes and the merits and risks of an investment in the Shares and the Notes Purchaser acknowledges and affirms that it has completed its own independent investigation, analysis and evaluation of the Companies and the Companies Subsidiaries and the Notes and that it has made all such reviews and inspections of the business, assets, results of operations and condition (financial or otherwise) of the Companies and the Companies Subsidiaries as it has deemed necessary or appropriate, and that in making its decision to enter into this Agreement and to consummate the transactions contemplated hereby it has relied on its own independent investigation, analysis, and evaluation of the Companies and the Companies Subsidiaries and the Notes and the representations and warranties of the Seller and the Note Holders set forth in Articles II and III , as applicable. Purchaser acknowledges and agrees that in its or its Affiliates’ capacity as voting members of the boards of directors or other governing bodies of the Companies Subsidiaries and as shareholder or owner of an interest in each of the Companies Subsidiaries it is deemed to have knowledge of the information made available in the data room, through management presentations and site visits, and that no such information shall form the basis for a breach or inaccuracy of any representation or warranty of Seller or the Note Holders set forth in this Agreement.

               (b) Purchaser acknowledges that the business operations and financial condition of the Companies Subsidiaries are subject to considerable distress, and that the bankruptcy of one or more of the Companies Subsidiaries is a material probability or likelihood. Purchaser further acknowledges that it has had a full opportunity to investigate the business and affairs of the Companies Subsidiaries with respect to these issues and understands the risks of their financial failure. Purchaser and its Affiliates have acknowledged and agreed to take all risk of insolvency and/or bankruptcy of the Companies and the Companies Subsidiaries, including without limitation, a filing for insolvency by any Company or any of the Companies Subsidiaries or a declaration of insolvency, or similar Governmental Order, by any Governmental Entity. Any such declaration or Governmental Order shall, with respect to Seller or any Note Holder, under no circumstance constitute a breach of any obligation, representation, warranty, covenant or condition to Closing, nor shall otherwise constitute an event giving rise to the right of Purchaser to modify or terminate its obligations to close the Transaction pursuant to the Agreement. Purchaser further agrees that prior to the Closing, to the extent that Seller or its

Affiliates reasonably believes upon the advice of counsel such action to be required from a legal standpoint, Seller and its Affiliates shall have the right to effect a bankruptcy filing for one or more Companies Subsidiaries in their sole discretion after consultation with Purchaser, and that such bankruptcy filings shall not constitute a breach of this Agreement or an event that constitutes a failure of condition to Closing or an event that gives rise to a right to terminate this Agreement. For the avoidance of doubt, under no circumstances shall Seller be required or expected to provide any equity or debt financing to any of the Operating Companies.

          4.5 Brokers and Finders . Purchaser has not entered into any written agreement or arrangement entitling any agent, broker, investment banker, financial advisor or other firm or Person to any broker’s or finder’s fee or any other commission or similar fee in connection with any of the transactions contemplated by this Agreement.

          4.6 No Knowledge of Seller or Note Holders Breach . Neither Purchaser nor any of its Affiliates has Knowledge of any breach or inaccuracy, or of any facts or circumstances which may constitute or give rise to a breach or inaccuracy, of any representation or warranty of Seller or the Note Holders set forth in this Agreement.

ARTICLE V

COVENANTS

          5.1 Notification to the CNDC and ENARGAS; Negative Antitrust and ENARGAS Decision; Transfer of Shares to a Third Purchaser .

               (a)  Notification of the Transactions to the CNDC and ENARGAS. No later than seven (7) days from the Closing Date, and at any subsequent date that may be required by instruction of the CNDC and/or ENARGAS, Seller and Purchaser shall (i) cooperate with one another and file all notifications, applications, registrations, filings, declarations and reports required under the Antitrust Law and the Gas Law relating to the Transactions, and (ii) use their reasonable efforts to take, or cause to be taken, all appropriate action, and to do, or cause to be done, all things necessary, proper or advisable to obtain the Argentine Transaction Approvals.

               (b) Negative Antitrust Decision and/or Negative ENARGAS Decision.

          (i) Purchaser hereby expressly acknowledges and undertakes that the entire risk as to a Negative Antitrust Decision and/or Negative ENARGAS Decision and/or the issuance of any resolution, decree, judgment, injunction or other order, whether temporary, preliminary or permanent, oral or in writing, in each case pursuant to Antitrust Law and/or Gas Law, as the case may be, that may prohibit, prevent or restrict the consummation of the Transactions rests exclusively with Purchaser.

          (ii) Purchaser shall be the sole responsible party to perform any and all actions required by the Negative Antitrust Decision and/or Negative ENARGAS Decision including, but not limited to, (x) a divesture of Purchaser’s businesses, product lines or assets in favor of a third party, at its own risk, cost and expense; and (y) appointment of the management of the Companies following directives by the CNDC or other antitrust authority. Notwithstanding anything contained herein to the contrary,

none of Seller or its Affiliates shall be required to (A) divest any of its respective businesses, product lines or assets that are not transferred to Purchaser or (B) take or agree to take any other action or agree to any limitation that could reasonable be expected to (1) result in a adverse effect on its business, assets, condition (financial or otherwise) or (2) deprive Seller or any Note Holder, or any Affiliate of any of them, of any benefit of the Transactions

          (iii) Each Party shall promptly give to the other Party notice of all information in its possession regarding the Negative Antitrust Decision and/or the Negative ENARGAS Decision or its consequences and promptly transmit to the other Party a copy of all documents received or sent in that respect. Each Party shall also respond promptly to any reasonable request for information from the other Party with respect to a Negative Antitrust Decision and/or Negative ENARGAS Decision or its consequences.

          (iv) In furtherance of the foregoing, Seller shall execute and deliver, or cause to be executed and delivered, all such documents and instruments and shall take, or cause to be taken, all such further or other actions, as Purchaser may reasonably deem necessary to permit Purchaser to have complete control of the Companies as from the date hereof.

               (c)  Waiver by Purchaser . None of the Seller, its Affiliates or any of their respective officers, directors or employees shall be held liable for any loss or damage arising out of any of the events provided for in Section 5.1(b) hereof.

               (d) [Intentionally Omitted.]

               (e)  Indemnification .

          (i) Subject only to the terms and limitations set forth in this Section 5.1, Purchaser shall indemnify, defend and hold harmless Seller or any of its Affiliates and their respective directors, officers, employees, successors, permitted assigns, advisors, agents, or representatives (whether or not also indemnified by any other Person under any other document) from and against any penalties, fines, administrative sanctions, costs and expenses (including reasonable attorneys’ fees as provided in Section 5.1(e)(ii) below) which directly relate to, or arise out of, any of the events provided for in Section 5.1(b), including fines, penalties and/or administrative sanctions imposed, or handed down, by the CNDC, ENARGAS, the Secretariat of Internal Trade and/or any other agency, tribunal or court because the Transactions is ultimately deemed to breach the Antitrust Law and/or the Gas Law (a “ Claim ”).

          (ii) Within five (5) days following the receipt by Seller of a Claim, Seller shall promptly give notice of such Claim to Purchaser in writing. Purchaser shall assume and control the defense of a Claim with counsel of their own choice it being understood, however, that Seller may retain, at its own cost, separate co-counsel and participate fully in the defense of the Claim with full access to all relevant information.

          (iii) If a Claim involves a fine, penalty and/or an administrative sanction to Seller, then at Seller’s option Purchaser and Parent shall be jointly and severally liable to (i) pay the amount of the relevant fine, penalty and/or an administrative sanction; or (ii) deposit in escrow at Seller’s satisfaction the amount of the relevant fine, penalty and/or an administrative sancti