SIXTH SUPPLEMENTAL INDENTURE SIXTH SUPPLEMENTAL INDENTURE, dated as of July 26, 2002 (the "Supplemental Indenture") between PECOM ENERGIA S.A., a sociedad anonima duly organized and existing under the laws of Argentina (the "Company"), and CITIBANK, N.A., a national banking association incorporated and existing under the laws of the United States of America, as Trustee (the "Trustee"). All capitalized terms used herein but not defined herein shall have the meanings given in the Indenture, unless otherwise indicated. WHEREAS, the Company and the Trustee are parties to that certain Indenture dated as of May 1, 1998 (the "Indenture") pursuant to which the Company issued its 9% Series B Notes due 2006 (the "Series B Notes"); WHEREAS, pursuant to Section 902 of the Indenture, the Company, when authorized by a Corporate Resolution, and the Trustee, with the consent or vote of the Holders of not less than a majority in aggregate principal amount of the Outstanding Securities thereby affected, may amend or supplement certain provisions of the Indenture; WHEREAS, the Company desires to amend the Indenture to delete certain covenants and other provisions contained therein with respect to the Series B Notes; WHEREAS, pursuant to an offering memorandum and a pricing supplement each dated June 10, 2002 (the "Offer"), the Company offered to exchange all of the Company's outstanding Series B Notes for its 9% Notes due 2009 (the "New Notes"), and solicited proxies to the amendments to the Indenture described therein; WHEREAS, Holders of at least a majority in principal amount of the outstanding Series B Notes have approved a Corporate Resolution at a duly convened noteholders meeting (the "Meeting") which authorizes the Company to so amend the Indenture; WHEREAS, the CNV confirmed that the Meeting conformed with its legal requirements; and WHEREAS, by entering into this Supplemental Indenture, the Company and the Trustee have consented to amend the Indenture in accordance with the terms and conditions herein. NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged by the Company and the Trustee hereby agree for the benefit of each other and the equal and ratable benefit of the Holders of the Series B Notes as follows: 1 ARTICLE I AMENDMENTS Section 1.01. Amendments to the Indenture. On the Operative Date (as hereinafter defined) the Indenture is amended as set forth herein. (a) Section 501 of the Indenture is hereby amended by deleting paragraphs (3) through (12), each in its entirety and inserting in lieu of each such paragraph "[Intentionally Deleted.]", and by deleting the definition of "Bankruptcy Law" appearing at the end of Section 501. (b) Section 801 of the Indenture is hereby amended by deleting it in its entirety and inserting in lieu thereof "[Intentionally Deleted.]". (c) Section 1004 of the Indenture is hereby amended by deleting it in its entirety and inserting in lieu thereof "[Intentionally Deleted.]". (d) Section 1005 of the Indenture is hereby amended by deleting it in its entirety and inserting in lieu thereof "[Intentionally Deleted.]". (e) Section 1006 of the Indenture is hereby amended by deleting it in its entirety and inserting in lieu thereof "[Intentionally Deleted.]". (f) Section 1007 of the Indenture is hereby amended by deleting it in its entirety and inserting in lieu thereof "[Intentionally Deleted.]". (g) Section 1009 of the Indenture is hereby amended by deleting it in its entirety and inserting in lieu thereof "[Intentionally Deleted.]". (h) Section 101 of the Indenture is hereby amended by deleting those definitions which appear solely in the text deleted from the Indenture pursuant to the amendments contained herein. ARTICLE II CONDITION PRECEDENT AND OPERATIVE DATE Section 2.01. Compliance with and Fulfillment of Conditions Precedent. The Company has complied with all conditions precedent provided in the Indenture and this Supplemental Indenture to the execution and delivery of this Supplemental Indenture (along with such documentation relating thereto as the Trustee shall require, including, without limitation, an Opinion of Counsel as to the enforceability of the Supplemental Indenture and an Officers' Certificate). Section 2.02. Operative Date. This Supplemental Indenture shall become operative on the date (the "Operative Date") on which Pecom Energia S.A. accepts all Series B Notes validly 2 tendered and not withdrawn pursuant to the Offer and has irrevocably delivered to the Exchange Agent the New Notes for delivery to the holders thereof. ARTICLE III MISCELLANEOUS Section 3.01. Relation to Existing Indenture. This Supplemental Indenture constitutes an integral part of the Indenture (the provisions of which, as modified by the Supplemental Indenture, shall apply to the Series B Notes) in respect of the Series B Notes but shall not modify, amend or otherwise affect the Indenture insofar as it relates to any other Series of Securities or affect in any manner the terms or conditions of the Securities of any other Series. Section 3.02. Construction. For all purposes of this Supplemental Indenture, except as otherwise herein expressly provided or unless the context otherwise requires: (i) the terms and expressions used herein shall have the same meanings as corresponding terms and expressions used in the Indenture; and (ii) the words "herein," "hereof" and "hereby" and other words of similar import used in this Supplemental Indenture refer to this Supplemental Indenture as a whole and not to any particular Section hereof. Section 3.03. Trustee Acceptance. The Trustee accepts the amendment of the Indenture effected by this Supplemental Indenture, as hereby amended, but only upon the terms and conditions set forth in the Indenture, as hereby amended, including the terms and provisions defining and limiting the liabilities and responsibilities of the Trustee in the performance of its duties and obligations under the Indenture, as hereby amended. Without limiting the generality of the foregoing, the Trustee has no responsibility for the correctness of the recitals of fact herein contained which shall be taken as the statements of the Company, and makes no representations as to the validity or enforceability against the Company. Section 3.04. Indenture Ratified. Except as expressly amended hereby, the Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force and effect. Section 3.05. Parties Bound. This Supplemental Indenture shall form a part of the Indenture for all purposes, and every holder of the Series B Notes heretofore or hereafter authenticated and delivered shall be bound hereby. Upon the execution of this Supplemental Indenture, the Indenture and the Series B Notes theretofore issued shall be deemed to be modified and amended in accordance with this Supplemental Indenture and the respective rights, limitation of rights, obligations, duties and immunities under the Indenture of the Company and the Trustee and the Holders of the Series B Notes shall thereafter be determined, exercised and enforced thereunder subject in all respects to such modifications and amendments, and all the terms and conditions of this Supplemental Indenture shall be and be deemed to be part of the terms and conditions of the Indenture and the Series B Notes theretofore issued for any and all purposes. Section 3.06. Successors and Assignees. This Supplemental Indenture shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns. 3 Section 3.07. Counterparts. This Supplemental Indenture may be executed in any number of counterparts, each of which when so executed shall be deemed to be an original, and all of such counterparts shall together constitute one and the same instrument. Section 3.08. Severability. In case any provision in this Supplemental Indenture shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby. Section 3.09. Headings. The headings of the Articles and Sections of this Supplemental Indenture have been inserted for convenience of reference only and are not to be considered part of this Supplemental Indenture and shall in no way modify or restrict any of the terms or provisions hereof. Section 3.10. Governing Law. This Supplemental Indenture shall be governed by and construed in accordance with the internal laws of the State of New York without giving effect to principles of conflicts of laws. 4 IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed as of the date first above written. PECOM ENERGIA S.A. By:_______________________________ Name: Title: By:_______________________________ Name: Title: CITIBANK, N.A., as Trustee By:_______________________________ Name: Title: 5