SOUTHERN INDIANA GAS AND ELECTRIC COMPANY WITH BANKERS TRUST COMPANY, as Trustee SUPPLEMENTAL INDENTURE Providing among other things for FIRST MORTGAGE BONDS ___% Senior Note Series of 1999 due 20__ Dated as of July __, 1999 SUPPLEMENTAL INDENTURE, dated as of July __, 1999, between SOUTHERN INDIANA GAS AND ELECTRIC COMPANY, a corporation organized and existing under the laws of the State of Indiana (hereinafter called the "Company"), party of the first part, and BANKERS TRUST COMPANY, a corporation organized and existing under the laws of the State of New York, as Trustee under the Mortgage hereinafter referred to, party of the second part. WHEREAS, the Company heretofore executed and delivered to Bankers Trust Company, as Trustee (hereinafter called the "Trustee"), a certain Indenture of Mortgage and Deed of Trust dated as of April 1, 1932, to secure an issue of bonds of the Company, issued and to be issued in series, from time to time, in the manner and subject to the conditions set forth in the said Indenture, and the said Indenture has been amended and supplemented by Supplemental Indentures dated as of August 31, 1936, October 1, 1937, March 22, 1939, July 1, 1948, June 1, 1949, October 1, 1949, January 1, 1951, April 1, 1954, March 1, 1957, October 1, 1965, September 1, 1966, August 1, 1968, May 1, 1970, August 1, 1971, April 1, 1972, October 1, 1973, April 1, 1975, January 15, 1977, April 1, 1978, June 4, 1981, January 20, 1983, November 1, 1983, March 1, 1984, June 1, 1984, November 1, 1984, July 1, 1985, November 1, 1985, June 1, 1986, November 15, 1986, January 15, 1987, December 15, 1987, December 13, 1990, April 1, 1993, May 1, 1993 and June 1, 1993, which Indenture as so amended and supplemented is hereinafter referred to as the "Mortgage" and as further supplemented by this Supplemental Indenture is hereinafter referred to as the "Indenture"; and WHEREAS, the Mortgage provides that the Company and the Trustee may, from time to time, enter into such indentures supplemental to the Mortgage as shall be deemed by them necessary or desirable, to establish the terms and provisions of any series of bonds to be issued under said Mortgage and to add to the covenants and agreements of the Company for the protection of the holders of bonds and of the mortgaged and pledged property; and WHEREAS, the Company and the Trustee deem it necessary or desirable to enter into this Supplemental Indenture for such purposes; and WHEREAS, the Company by appropriate corporate action in conformity with the terms of the Indenture has duly determined to create a series of bonds to be issued under the Indenture to be designated as "First Mortgage Bonds, ___% Senior Note Series of 1999 due 20__" (hereinafter sometimes referred to as "bonds of the Thirty-Eighth Series"), the bonds of which series are to bear interest at the rate per annum set forth in the title thereof; and WHEREAS, the definitive registered (without coupons) bonds of the Thirty-Eighth Series and the Trustee's certificate of authentication to be borne by such bonds are to be substantially in the following forms, respectively: [FORM OF FULLY REGISTERED BOND OF THE THIRTY-EIGHTH SERIES] [FORM OF FACE OF BOND] SOUTHERN INDIANA GAS AND ELECTRIC COMPANY FIRST MORTGAGE BOND, ___% SENIOR NOTE SERIES OF 1999 DUE 20__ No. _______ $ __________ Southern Indiana Gas and Electric Company, a corporation of the State of Indiana (hereinafter called the "Company"), for value received, hereby promises to pay to ______________________________ or registered assigns ______________________________ dollars, on July __, 20__ at the office or agency of the Company in the Borough of Manhattan, The City of New York, New York, in any coin or currency of the United States of America which at the time of payment is legal tender for the payment of public and private debts, and to pay to the registered owner hereof interest thereon from the interest payment date (________ 1 or ________ 1) next preceding the date of this bond unless the date hereof is prior to ________ 1, 1999, in which case from ________ 1, 1999 (or, of this bond is dated between the record date for any interest payment date and such interest payment date, then from such interest payment date), at the rate of _____________ per cent (__%) per annum in like coin or currency, payable at said office or agency on ________ 1 and ________ 1 in each year, until the Company's obligation with respect to the payment of such principal shall have been discharged. The interest so payable on any ________ 1 or ________ 1 will, subject to certain exceptions provided in the Mortgage hereinafter mentioned, be paid to the person in whose name this bond is registered at the close of business on the record date, which shall be the ________ 15 or ________ 15, as the case may be, next preceding such interest payment date, or, if such ________ 15 or ________ 15 shall be a legal holiday or a day on which banking institutions in the Borough of Manhattan, The City of New York, New York, are authorized or obligated by law to close, the next preceding day which shall not be a legal holiday or a day on which such institutions are so authorized or obligated to close. The provisions of this bond are continued on the reverse hereof and such continued provisions shall for all purposes have the same effect as though fully set forth at this place. This bond shall not become obligatory until Bankers Trust Company, the Trustee under the Mortgage, or its successor thereunder, shall have signed the form of certificate endorsed hereon. IN WITNESS WHEREOF, Southern Indiana Gas and Electric Company has caused this bond to be signed in its name by its President or a Vice President, by his signature or a facsimile thereof, and a facsimile of its corporate seal to be imprinted hereon, attested by its Secretary or an Assistant Secretary, by his signature or a facsimile thereof. 2 Dated: SOUTHERN INDIANA GAS AND ELECTRIC COMPANY By: ------------------------------------- Name: Title: President and Chief Executive Officer Attest: - ------------------------------- Secretary 3 [FORM OF TRUSTEE'S CERTIFICATE] This bond is one of the bonds of the series designated therein, described in the within-mentioned Mortgage. BANKERS TRUST COMPANY, as Trustee, By: ------------------------------------- Name: Title: [FORM OF REVERSE OF BOND] SOUTHERN INDIANA GAS AND ELECTRIC COMPANY FIRST MORTGAGE BOND, __% SENIOR NOTE SERIES OF 1999 DUE 20__ This bond is one of an issue of First Mortgage Bonds of the Company, issuable in series, and is one of the series designated in the title hereof, all issued and to be issued under and equally secured (except as to any sinking fund established in accordance with the provisions of the Mortgage hereinafter mentioned for the bonds of any particular series) by an Indenture of Mortgage and Deed of Trust, dated as of April 1, 1932, executed by the Company to Bankers Trust Company, as Trustee, as amended and supplemented by indentures supplemental thereto, to which Indenture as so amended and supplemented (herein referred to as the Mortgage) reference is made for a description of the property mortgaged and pledged, the nature and extent of the security, the rights of the holders of the bonds in respect thereof and the terms and conditions upon which the bonds are secured. The principal hereof may be declared or may become due on the conditions, with the effect, in the manner and at the time set forth in the Mortgage, upon the occurrence of a completed default as provided in the Mortgage. 4 The bonds of this series shall be redeemable as follows: [ ] 5 This bond is transferable as prescribed in the Mortgage by the registered owner hereof in person, or by his duly authorized attorney, at the office or agency of the Company in the Borough of Manhattan, The City of New York, New York, upon surrender and cancellation of this bond, and thereupon, a new fully registered bond of the same series for a like principal amount will be issued to the transferee in exchange thereof as provided in the Mortgage, and upon payment, if the Company shall require it, of the charges therein prescribed. The Company and the Trustee may deem and treat the person in whose name this bond is registered as the absolute owner for the purpose of receiving payment of or on account of the principal, premium, if any, and interest due hereon and for all other purposes. The bonds of this series are issuable as registered bonds without coupons in denominations of $1,000 and authorized multiples thereof. In the manner and upon payment of the charges prescribed in the Mortgage, registered bonds without coupons of this series may be exchanged for a like aggregate principal amount of registered bonds without coupons of other authorized denominations of the same series, upon presentation and surrender thereof, for cancellation, to the Trustee at its principal corporate trust office in the Borough of Manhattan, The City of New York, New York. No recourse shall be had for the payment of the principal of, premium, if any, or interest on this bond against any incorporator or any past, present or future subscriber to the capital stock, stockholder, office or director of the Company or of any predecessor or successor corporation, either directly or through the Company or any predecessor or successor corporation, under any rule of law, statute or constitution or by the enforcement of any assessment or otherwise, all such liability of incorporators, subscribers, stockholders, officers and directors being released by the holder or owner hereof by the acceptance of this bond and being likewise waived and released by the terms of the Mortgage. Pursuant to the Mortgage, the holder or owner of this bond by his acceptance hereof is deemed to have agreed to amendments to the Mortgage which will eventually permit certain amendments to the Mortgage with the consent of the holders of 66% of the principal amount of the outstanding bonds of all series issued under the Mortgage, which redefine, effective at such time as all bonds of each series of bonds issued under the Mortgage prior to January 1, 1977 are no longer outstanding, the amounts required to be spent by the Company under the Mortgage for the repair, maintenance, renewal and replacement of its property and which authorize the Company, effective at such time as all bonds of each series issued under the Mortgage on or prior to May 31, 1986 are no longer outstanding, to designate bonds of any series as the bonds to be redeemed pursuant to Section 36B of the Mortgage and to do so at any time that cash for such purpose is on deposit with Trustee pursuant to the provisions of that Section. [END OF FORM OF BOND] 6 and WHEREAS, all things necessary to make the bonds of the Thirty-Eighth Series, when authenticated by the Trustee and issued as in the Indenture provided, the valid, binding and legal obligations of the Company, entitled in all respects to the security of the Indenture, have been done and performed, and the creation, execution and delivery of this Supplemental Indenture has in all respects been duly authorized; and WHEREAS, the Company and the Trustee deem it advisable to enter into this Supplemental Indenture for the purposes above stated and for the purpose of describing the bonds of the Thirty-Eighth Series, and of providing the terms and conditions of redemption thereof; NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH: That Southern Indiana Gas and Electric Company, in consideration of the premises and of one dollar to it duly paid by the Trustee at or before the ensealing and delivery of these presents, the receipt whereof is hereby acknowledged, and of the purchase and acceptance of the bonds issued or to be issued hereunder by the holders or registered owners thereof, and in order to secure the payment of the principal, premium, if any, and interest of all bonds at any time issued and outstanding under the Indenture, according to their tenor and effect, and the performance of all of the provisions hereof and of said bonds, hath granted, bargained, sold, released, conveyed, assigned, transferred, pledged, set over and confirmed and by these presents doth grant, bargain, sell, release, convey, assign, transfer, pledge, set over and confirm unto Bankers Trust Company, as Trustee, and to its successor or successors in said trust, and to its and their assigns forever, all the properties of the Company located in the State of Indiana described in Schedule A (which is identified by the signature of an officer of each party hereto at the end thereof) hereto annexed and hereby made a part hereof and does hereby confirm that the Company will not cause or consent to a partition, either voluntary or through legal proceedings, of property, whether herein described or heretofore or hereafter acquired, in which its ownership shall be as a tenant in common, except as permitted by and in conformity with the provisions of the Indenture and particularly of Article X thereof. TOGETHER WITH all and singular the tenements, hereditaments and appurtenances belonging or in any wise appertaining to the aforesaid property or any party thereof, with the reversion and reversions, remainder and remainders and (subject to the provisions of Article X of the Indenture), the tolls, rents, revenues, issues, earnings, income, product and profits thereof, and all the estate, right title interest and claim whatsoever, at law as well as in equity, which the Company now has or may hereafter acquire in and to the aforesaid property and franchises and every part and parcel thereof. TO HAVE AND TO HOLD all such properties, real, personal and mixed, mortgaged, pledged or conveyed by the Company as aforesaid, or intended so to be, unto the Trustee and its successors and assigns forever. 7 IN TRUST, NEVERTHELESS, upon the terms and trusts of the Indenture, for those who shall hold the bonds and coupons issued and to be issued thereunder, or any of them, without preference, priority or distinction as to lien of any of said bonds and coupons over any others thereof by reason of priority in the time of the issue or negotiation thereof, or otherwise howsoever, subject, however, to the provisions in reference to extended, transferred or pledged coupons and claims for interest set forth in the Indenture (and subject to any sinking funds that may be created for the benefit of any particular series). PROVIDED, HOWEVER, and these presents are upon the condition that, if the Company, its successors or assigns, shall pay or cause to be paid, the principal of, premium, if any, and interest on said bonds, at the times and in the manner stipulated therein and herein, and shall keep, perform and observe all and singular the covenants and promises in said bonds and in the Indenture expressed to be kept, performed and observed by or on the part of the Company, then this Supplemental Indenture and the estate and rights hereby granted shall cease, determine and be void, otherwise to be and remain in full force and effect. IT IS HEREBY COVENANTED, DECLARED AND AGREED, by the Company, that all such bonds and coupons are to be issued, authenticated and delivered, and that all property subject or to become subject hereto is to be held, subject to the further covenants, conditions, uses and trusts in the Indenture set forth, and the Company, for itself and its successors and assigns, does hereby covenant and agree to and with the Trustee and its successor or successors in such trust, for the benefit of those who shall hold said bonds and interest coupons, or any of them, as follows: SECTION 1. Bonds of the Thirty-Eighth Series shall mature on the date set forth in the form of bond relating thereto hereinbefore set forth, shall bear interest at the rate per annum set forth in the title thereof, payable semi-annually, on ________ 1 and ________ 1 in each year, and all bonds of said series shall be designated as hereinbefore in the fourth Whereas clause set forth. Principal of, premium, if any, and interest on said bonds shall be payable in any coin or currency of the United States of America which at the time of payment is legal tender for the payment of public and private debts, at the office or agency of the Company in the Borough of Manhattan, The City of New York, New York. Definitive bonds of said series may be issued, originally or otherwise, only as registered bonds without coupons; and they and the Trustee's certificate of authentication shall be substantially in the forms hereinbefore recited, respectively. Definitive registered bonds of the Thirty-Eighth Series may be issued in the denomination of $1,000 and in such other denominations (in multiples of $1,000) as the Board of Directors of the Company shall approve, and execution and delivery to the Trustee for authentication shall be conclusive evidence of such approval. In the manner and upon payment of the charges prescribed in the Indenture, registered bonds without coupons of said series may be exchanged for a like aggregate principal amount of registered bonds without coupons of other authorized denominations of the same series, upon presentation and surrender thereof for cancellation to the Trustee at its principal corporate trust office in the Borough of Manhattan, The City of New York, New York. However, notwithstanding the provisions of Section 12 of the Indenture, no charge shall be made upon any transfer or exchange of bonds of said series other than for any tax 8 or taxes or other governmental charge required to be paid by the Company. The form of the temporary bonds of said series shall be in substantially the form of the form of registered bond hereinbefore recited with such appropriate changes therein as are required on account of the temporary nature thereof. Said temporary bonds of said series shall be in registered form without coupons and shall be exchangeable for definitive bonds of said series when prepared. The person in whose name any registered bond without coupons of the Thirty-Eighth Series is registered at the close of business on any record date (as hereinbelow defined) with respect to any interest payment date shall be entitled to receive the interest payable on such interest payment date notwithstanding the cancellation of such registered bond upon any transfer or exchange thereof subsequent to the record date and prior to such interest payment date, except if and to the extent the Company shall default in the payment of the interest due on such interest payment date, in which case such defaulted interest shall be paid to the person in whose name such bond is registered either at the close of business on the day preceding the date of payment of such defaulted interest or on a subsequent record date for such payment if one shall have been established as hereinafter provided. A subsequent record date may be established by or on behalf of the Company by notice mailed to the holders of bonds not less than ten days preceding such record date, which record date shall be not more than thirty days prior to the subsequent interest payment date. The term "record date" as used in this Section with respect to any regular interest payment date shall mean the ________ 15 or ________ 15, as the case may be, next preceding such interest payment date, or, if such ________ 15 or ________ 15 shall be a legal holiday or a day on which banking institutions in the Borough of Manhattan, The City of New York, New York, are authorized or obligated by law to close, the next preceding day which shall not be a legal holiday or day on which such institutions are so authorized or obligated to close. Except as provided in this Section, every registered bond without coupons of the Thirty-Eighth Series shall be dated and shall bear interest as provided in Section 10 of the Indenture; provided, however, that so long as there is no existing default in the payment of interest on the bonds, the holder of any bond authenticated by the Trustee between the record date for any interest payment date and such interest payment date shall not be entitled to the payment of the interest due on such interest payment date and shall have no claim against the Company with respect thereto; and provided, further, that, if and to the extent the Company shall default in the payment of the interest due on such interest payment date, then any such bond shall bear interest from the ________ 1 or ________ 1, as the case may be, next preceding the date of such bond, to which interest has been paid or, if the Company shall be in default with respect to the interest due on ________ 1, 1999, then from ________ 1, 1999. Bonds of the Thirty-Eighth Series shall be redeemable as follows: [ ] 9 SECTION 2. The Company's obligation to make payments with respect to the principal of, premium, if any, and/or interest on, the bonds of the Thirty-Eighth Series shall be fully or partially satisfied and discharged to the extent that, at the time any such payment shall be due, the corresponding amount then due of principal of, and/or premium, if any, and/or interest then due on, the senior notes (the "Senior Notes") issued pursuant to the Indenture (for Senior Notes) dated as of July __, 1999, between the Company and Bankers Trust Company, the Senior Note Trustee (the "Senior Note Indenture") shall have been fully or partially paid (other than by the application of the proceeds of a payment in respect of such bonds of the Thirty-Eighth Series), as the case may be, or there shall have been deposited with the Senior Note Trustee pursuant to the Senior Note Indenture trust funds sufficient under such indenture to fully or partially pay, as the case may be, the corresponding amount then due of principal of, and/or premium, if any, and/or interest on, the Senior Notes (other than by the application of the proceeds of a payment in respect of such bonds of the Thirty-Eighth Series). Upon payment of the principal of, and premium if any, and interest due on the Senior Notes, whether at maturity or prior to maturity by acceleration, redemption or otherwise, or upon provision for the payment thereof having been made in accordance with the Senior Note Indenture (other than by the application of the proceeds of a payment in respect of such bonds of the Thirty-Eighth Series), bonds of the Thirty-Eighth Series in a principal amount equal to the principal amount of Senior Notes so paid or for which such provision for payment has been made shall be deemed fully paid, satisfied and discharged and the obligations of the Company thereunder shall be terminated and such bonds of the Thirty-Eighth Series shall be surrendered to and cancelled by the Trustee. From and after the Release Date (as defined in the Senior Note Indenture), the bonds of the Thirty-Eighth Series shall be deemed fully paid, satisfied and discharged and the obligation of the Company thereunder shall be terminated. On the Release Date, the bonds of the Thirty-Eighth Series shall be surrendered to and cancelled by the Trustee. SECTION 3. The Company covenants that the provisions of Section 36A of the Indenture and of Section 1.02 of the Supplemental Indenture dated as of July 1, 1948, which are to remain in effect so long as any bonds of the series referred to in said Section shall be outstanding under the Indenture, shall remain in full force and effect so long as any bonds of the Thirty-Eighth Series shall be outstanding under the Indenture. SECTION 4. Except as herein otherwise expressly provided, no duties, responsibilities or liabilities are assumed, or shall be construed to be assumed, by the Trustee by reason of this Supplemental Indenture, other than as set forth in the Mortgage. The Trustee shall not be responsible for the recitals herein or in the bonds (except the Trustee's certificate of authentication), all of which are made by the Company solely. Without limiting the generality of the foregoing, the Trustee shall have no responsibility for, and shall incur no liability with respect to, the form or substance of the Certificates or the form or substance of any agreement under which any banking or other financial institution receives the Deposit or makes the Payments nor shall the Trustee have any responsibility, or incur any liability, with respect to the performance of such banking or other financial institution under any such agreement. 10 SECTION 5. As supplemented and amended by this Supplemental Indenture, the Mortgage is in all respects ratified and confirmed, and the Mortgage and this Supplemental Indenture shall be read, taken and construed as one and the same instrument. SECTION 6. This Supplemental Indenture may be executed in several counterparts and all such counterparts executed and delivered, each as an original, shall constitute but one and the same instrument. 11 IN WITNESS WHEREOF, SOUTHERN INDIANA GAS AND ELECTRIC COMPANY, party of the first part hereto, and BANKERS TRUST COMPANY, party of the second part hereto, have caused these presents to be executed in their respective names by their respective Chairmen of the Board or Presidents or one of their Vice Presidents or Assistant Vice Presidents and their respective seals to be hereunto affixed and attested by their respective Secretaries or one of their Assistant Secretaries, all as of the day and year first above written. (SEAL) SOUTHERN INDIANA GAS AND ELECTRIC COMPANY, By: ------------------------------------ Name: Title: Attest: - ----------------------- Name: Title: (SEAL) BANKERS TRUST COMPANY, By: ------------------------------------ Name: Title: Attest: - ----------------------- Name: Title: 12 STATE OF INDIANA ) ) ss.: COUNTY OF VANDERBURGH ) On this __ day of July, 1999, before me, the undersigned, a notary public in and for the county and state aforesaid, personally came ___________________, to me known, who being by me duly sworn, did depose and say that he resides at _________________________________; that he is _____________________ of SOUTHERN INDIANA GAS AND ELECTRIC COMPANY, one of the corporations described in and which executed the foregoing instrument; that he knows the seal of the said corporation; that the seal affixed to said instrument is such corporate seal; that it was so affixed by order of the Board of Directors of said corporation and that he signed his name thereto by like order; and the said _____________________ acknowledged the execution of the foregoing instrument on behalf of the said corporation as the voluntary act and deed of the said corporation for the uses and purposes therein set forth. IN WITNESS WHEREOF, I have hereunto set my hand and seal the day and year first above written. (SEAL) -------------------------- Notary Public My Commission Expires My County of Residence is 13 STATE OF NEW YORK ) ) ss.: COUNTY OF NEW YORK ) On this __ day of July, 1999, before me, the undersigned, a notary public in and for the county and state aforesaid, personally came ___________________, to me known, who being by me duly sworn, did depose and say that he resides at ____________________________; that he is a ______________________ of BANKERS TRUST COMPANY, one of the corporations described in and which executed the foregoing instrument; that he knows the seal of the said corporation; that the seal affixed to said instrument is such corporate seal; that it was so affixed by order of the Board of Directors of said corporation and that he signed his name thereto by like order; and the said ______________________ acknowledged the execution of the foregoing instrument on behalf of the said corporation as the voluntary act and deed of the said corporation for the uses and purposes therein set forth. IN WITNESS WHEREOF, I have hereunto set my hand and seal the day and year first above written. (SEAL) -------------------------- Notary Public My Commission Expires My County of Residence is 14 A-1 SCHEDULE A Detailed Description of Additional Properties Signed for identification ---------------------------------------- Name: Title: SOUTHERN INDIANA GAS AND ELECTRIC COMPANY ---------------------------------------- Name: Title: BANKERS TRUST COMPANY 15