8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of report (Date of earliest event reported):

March 9, 2007

Commission File Number	Exact Name of Registrant as Specified in Charter; State of Incorporation; Address and Telephone Number	IRS Employer Identification Number
1-14756	Ameren Corporation (Missouri Corporation) 1901 Chouteau Avenue St. Louis, Missouri 63103 (314) 621-3222	43-1723446
1-3672	Central Illinois Public Service Company (Illinois Corporation) 607 East Adams Street Springfield, Illinois 62739 (217) 523-3600	37-0211380
2-95569	CILCORP Inc. (Illinois Corporation) 300 Liberty Street Peoria, Illinois 61602 (309) 677-5271	37-1169387
1-2732	Central Illinois Light Company (Illinois Corporation) 300 Liberty Street Peoria, Illinois 61602 (309) 677-5271	37-0211050
1-3004	Illinois Power Company (Illinois Corporation) 370 South Main Street Decatur, Illinois 62523 (217) 424-6600	37-0344645

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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

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

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

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

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ITEM 1.01Entry into a Material Definitive Agreement.

Ameren Corporation (“Ameren”) previously announced that certain of its subsidiaries had entered into a new, multi-year committed bank credit facility (see Current Report on Form 8-K filed February 13, 2007 (the “February 13 Form 8-K”)).

After receipt of required regulatory approvals, effective March 9, 2007, Central Illinois Public Service Company, doing business as AmerenCIPS (“CIPS”), Central Illinois Light Company, doing business as AmerenCILCO (“CILCO”), and Illinois Power Company, doing business as AmerenIP (“IP” and collectively with CIPS and CILCO, the “Ameren Illinois Utilities”) became authorized to make borrowings and obtain letters of credit for their benefit under the $500 million multi-year, senior secured Credit Agreement, dated as of February 9, 2007 (the “2007 Credit Agreement”) described in the February 13 Form 8-K. A copy of the 2007 Credit Agreement was filed as Exhibit 10.1 to the February 13 Form 8-K.

From March 9, 2007, IP is authorized to make borrowings and obtain letters of credit for its benefit up to $200 million under the 2007 Credit Agreement (in addition to the $150 million of authority it has under a Credit Agreement dated July 14, 2006 (the “2006 Illinois Credit Agreement”)). CIPS and CILCO will continue to have borrowing capacity of $135 million and $150 million, respectively, under the 2006 Illinois Credit Agreement, but each will have the option of permanently reducing its borrowing capacity under the 2006 Illinois Credit Agreement and shifting, in one or more transactions, such capacity to the 2007 Credit Agreement up to the same limits. Until such time as CIPS or CILCO elects to increase its borrowing capacity under the 2007 Credit Agreement and issue first mortgage bonds as security for its obligations thereunder (as described in the February 13 Form 8-K and below), it will not constitute a “Borrower” under the 2007 Credit Agreement and will not be subject to the covenants thereof (except as a subsidiary of a Borrower).

See the February 13 Form 8-K for a summary of the terms of the 2007 Credit Agreement applicable to the Ameren Illinois Utilities. Each of the Ameren Illinois Utilities has entered into a Supplemental Indenture providing for the issuance of mortgage bonds as security for its obligations under the 2007 Credit Agreement. Copies of such Supplemental Indentures are filed herewith as Exhibits 4.2, 4.4 and 4.6.

ITEM 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

See Item 1.01 of the February 13 Form 8-K for a description of the 2007 Credit Agreement, a copy of which was attached thereto as Exhibit 10.1 and is incorporated herein by reference.

To secure its obligations under the 2007 Credit Agreement, CIPS has authorized the issuance of up to $135,000,000 of its First Mortgage Bonds, 2007 Credit Agreement Series (the “CIPS Credit Agreement Bonds”) under its Indenture of Mortgage and Deed of Trust dated October 1, 1941, as supplemented by the Supplemental Indenture dated as of March 1, 2007 (filed herewith as Exhibit 4.2) (the “CIPS Mortgage”).

To secure its obligations under the 2007 Credit Agreement, CILCO has authorized the issuance of up to $150,000,000 of its First Mortgage Bonds, 2007 Credit Agreement Series (the “CILCO Credit Agreement Bonds”) under its Indenture of Mortgage and Deed of Trust, as supplemented by the Supplemental Indenture dated as of March 1, 2007 (filed herewith as Exhibit 4.4) (the “CILCO Mortgage”).

To secure its obligations under the 2007 Credit Agreement, IP has issued $200,000,000 of its Mortgage Bonds, 2007 Credit Agreement Series (the “IP Credit Agreement Bonds, and together with the CIPS Credit Agreement Bonds and the CILCO Credit Agreement Bonds, the “Credit Agreement Bonds”) under its General Mortgage Indenture and Deed of Trust, as supplemented by the Supplemental Indenture dated as of March 1, 2007 (filed herewith as Exhibit 4.6) (the “IP Mortgage”).

The IP Credit Agreement Bonds were issued and delivered, and the CIPS Credit Agreement Bonds and the

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CILCO Credit Agreement Bonds will be issued and delivered to the extent such company increases its borrowing capacity under the 2007 Credit Agreement, to JPMorgan Chase Bank, N.A. as agent for the lenders under the 2007 Credit Agreement in order to evidence and secure the respective obligations of the Ameren Illinois Utilities under the 2007 Credit Agreement to make payments to the lenders under the 2007 Credit Agreement and to provide the lenders the benefit of the lien of the CIPS Mortgage, the CILCO Mortgage and the IP Mortgage, respectively, with respect to the applicable Credit Agreement Bonds.

The obligation of each Ameren Illinois Utility to make payments with respect to principal under the 2007 Credit Agreement will not give rise to an obligation to pay principal of the respective Credit Agreement Bonds except on the maturity date of such Ameren Illinois Utility’s obligations under the 2007 Credit Agreement or upon redemption of such Credit Agreement Bonds. Upon the occurrence of a default and an acceleration of an Ameren Illinois Utility’s obligations under the 2007 Credit Agreement, and upon notice given by the agent to the respective trustee under the CIPS Mortgage, the CILCO Mortgage or the IP Mortgage, as the case may be, the Credit Agreement Bonds of the applicable Ameren Illinois Utility will be subject to immediate redemption in the amount of all obligations owed by such Ameren Illinois Utility under the 2007 Credit Agreement.

If any Ameren Illinois Utility’s borrowing limit is permanently reduced under the 2007 Credit Agreement, such Ameren Illinois Utility’s obligation under its Credit Agreement Bond will be deemed discharged to that extent. The obligation of each Ameren Illinois Utility to make payments with respect to the interest on its Credit Agreement Bonds will be satisfied and discharged to the extent that, at the time that any such payment shall be due, the then due interest and/or fees of such Ameren Illinois Utility under the 2007 Credit Agreement has been paid. If any payment is made on interest and/or fees of an Ameren Illinois Utility under the 2007 Credit Agreement, a corresponding payment obligation with respect to the interest or fees on the respective Credit Agreement Bonds shall be deemed discharged in the same amount.

The Credit Agreement Bonds do not contain any provision regarding the release of the lien of the mortgage in the event of the retirement or redemption of all other mortgage bonds subject to the lien of the respective mortgage.

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ITEM 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit Number:	Registrant(s):	Title:
4.1 *	Ameren; CIPS	Indenture of Mortgage and Deed of Trust dated October 1, 1941, from CIPS to U.S. Bank National Association and Richard Prokosch (successors to Continental Illinois National Bank and Trust Company of Chicago and Edmond B. Stofft), as trustees, as supplemented (the “CIPS Mortgage”) (Annual Report on Form 10-K for the year ended December 31, 2006, Exhibits 4.50 through 4.63).
4.2 **	Ameren; CIPS	Supplemental Indenture dated as of March 1, 2007 to the CIPS Mortgage relating to the First Mortgage Bonds, 2007 Credit Agreement Series securing CIPS’ obligations under the Credit Agreement, dated as of February 9, 2007 (the "2007 Credit Agreement").
4.3 *	Ameren; CILCORP CILCO	Indenture of Mortgage and Deed of Trust between Illinois Power Company (predecessor in interest to CILCO) and Deutsche Bank Trust Company Americas (formerly known as Bankers Trust Company), as trustee, dated as of April 1, 1933, as supplemented (the “CILCO Mortgage”) (Annual Report on Form 10-K for the year ended December 31, 2006, Exhibits 4.75 through 4.82).
4.4 **	Ameren; CILCORP CILCO	Supplemental Indenture dated as of March 1, 2007 to the CILCO Mortgage relating to the First Mortgage Bonds, 2007 Credit Agreement Series securing CILCO’s obligations under the 2007 Credit Agreement.
4.5 *	Ameren; IP	General Mortgage Indenture and Deed of Trust dated as of November 1, 1992 between IP and BNY Midwest Trust Company (successor to Harris Trust and Savings Bank), as trustee, as supplemented (the “IP Mortgage”) (Annual Report on Form 10-K for the year ended December 31, 2006, Exhibits 4.85 through 4.95).
4.6 **	Ameren; IP	Supplemental Indenture dated as of March 1, 2007 to the IP Mortgage relating to the Mortgage Bonds, 2007 Credit Agreement Series securing IP’s obligations under the 2007 Credit Agreement.

*   Incorporated by reference as indicated.

** Filed herewith.

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This combined Form 8-K is being filed separately by Ameren Corporation, Central Illinois Public Service Company, CILCORP Inc., Central Illinois Light Company and Illinois Power Company (each a “registrant”). Information contained herein relating to any individual registrant has been filed by such registrant on its own behalf. No registrant makes any representation as to information relating to any other registrant.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, each registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. The signature for each undersigned company shall be deemed to relate only to matters having reference to such company or its subsidiaries.

AMEREN CORPORATION

(Registrant)

/s/ Jerre E. Birdsong                 

Jerre E. Birdsong

Vice President and Treasurer

CENTRAL ILLINOIS PUBLIC SERVICE COMPANY

(Registrant)

/s/ Jerre E. Birdsong                  

Jerre E. Birdsong

Vice President and Treasurer

CILCORP INC.

(Registrant)

/s/ Jerre E. Birdsong                  

Jerre E. Birdsong

Vice President and Treasurer

CENTRAL ILLINOIS LIGHT COMPANY

(Registrant)

/s/ Jerre E. Birdsong                  

Jerre E. Birdsong

Vice President and Treasurer

ILLINOIS POWER COMPANY

(Registrant)

/s/ Jerre E. Birdsong                  

Jerre E. Birdsong

Vice President and Treasurer

Date: March 14, 2007

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Exhibit Index

Exhibit Number:	Registrant(s):	Title:
4.1 *	Ameren; CIPS	Indenture of Mortgage and Deed of Trust dated October 1, 1941, from CIPS to U.S. Bank National Association and Richard Prokosch (successors to Continental Illinois National Bank and Trust Company of Chicago and Edmond B. Stofft), as trustees, as supplemented (the “CIPS Mortgage”) (Annual Report on Form 10-K for the year ended December 31, 2006, Exhibits 4.50 through 4.63).
4.2 **	Ameren; CIPS	Supplemental Indenture dated as of March 1, 2007 to the CIPS Mortgage relating to the First Mortgage Bonds, 2007 Credit Agreement Series securing CIPS’ obligations under the Credit Agreement, dated as of February 9, 2007 (the "2007 Credit Agreement").
4.3 *	Ameren; CILCORP CILCO	Indenture of Mortgage and Deed of Trust between Illinois Power Company (predecessor in interest to CILCO) and Deutsche Bank Trust Company Americas (formerly known as Bankers Trust Company), as trustee, dated as of April 1, 1933, as supplemented (the “CILCO Mortgage”) (Annual Report on Form 10-K for the year ended December 31, 2006, Exhibits 4.75 through 4.82).
4.4 **	Ameren; CILCORP CILCO	Supplemental Indenture dated as of March 1, 2007 to the CILCO Mortgage relating to the First Mortgage Bonds, 2007 Credit Agreement Series securing CILCO’s obligations under the 2007 Credit Agreement.
4.5 *	Ameren; IP	General Mortgage Indenture and Deed of Trust dated as of November 1, 1992 between IP and BNY Midwest Trust Company (successor to Harris Trust and Savings Bank), as trustee, as supplemented (the “IP Mortgage”) (Annual Report on Form 10-K for the year ended December 31, 2006, Exhibits 4.85 through 4.95).
4.6 **	Ameren; IP	Supplemental Indenture dated as of March 1, 2007 to the IP Mortgage relating to the Mortgage Bonds, 2007 Credit Agreement Series securing IP’s obligations under the 2007 Credit Agreement.

*    Incorporated by reference as indicated.

**  Filed herewith.

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EX-4.2

Exhibit 4.2

When recorded mail to:

James A. Tisckos

Central Illinois Public Service Company

607 East Adams Street

Springfield, IL 62739

Executed in 100 Counterparts, No. __.

Supplemental Indenture

dated as of March 1, 2007

Central Illinois Public Service Company

To

U.S. Bank National Association

and Richard Prokosch,

as trustees

(Supplemental to the Indenture of Mortgage or Deed of Trust

dated October 1, 1941, executed by Central Illinois Public Service Company

to Continental Illinois National Bank and Trust Company of Chicago

and Edmond B. Stofft, as trustees)

(Providing for First Mortgage Bonds, 2007 Credit Agreement Series)

This instrument was prepared by Steven R. Sullivan, Senior Vice President, General Counsel and Secretary of Central Illinois Public Service Company, c/o Ameren Corporation, One Ameren Plaza, 1901 Chouteau Avenue, St. Louis, Missouri 63103.

This Supplemental Indenture, dated as of March 1, 2007, made and entered into by and between CENTRAL ILLINOIS PUBLIC SERVICE COMPANY, a corporation organized and existing under the laws of the State of Illinois (hereinafter commonly referred to as the “Company”), and U.S. BANK NATIONAL ASSOCIATION (formerly U.S. Bank Trust National Association, formerly First Trust National Association, formerly First Trust of Illinois, National Association, successor trustee to Bank of America Illinois, formerly Continental Bank, formerly Continental Bank, National Association and formerly Continental Illinois National Bank and Trust Company of Chicago), a national banking association having its office or place of business in the City of Chicago, Cook County, State of Illinois (hereinafter commonly referred to as the “Trustee”), and Richard Prokosch (successor Co-Trustee), of the City of Oakdale, Washington County, State of Minnesota, as Trustees under the Indenture of Mortgage or Deed of Trust dated October 1, 1941, heretofore executed and delivered by the Company to Continental Illinois National Bank and Trust Company of Chicago and Edmond B. Stofft, as Trustees, as amended by the Supplemental Indentures dated, respectively, September 1, 1947, January 1, 1949, February 1, 1952, September 1, 1952, June 1, 1954, February 1, 1958, January 1, 1959, May 1, 1963, May 1, 1964, June 1, 1965, May 1, 1967, April 1, 1970, April 1, 1971, September 1, 1971, May 1, 1972, December 1, 1973, March 1, 1974, April 1, 1975, October 1, 1976, November 1, 1976, October 1, 1978, August 1, 1979, February 1, 1980, February 1, 1986, May 15, 1992, July 1, 1992, September 15, 1992, April 1, 1993, June 1, 1995, March 15, 1997, June 1, 1997, December 1, 1998, June 1, 2001, October 1, 2004, June 1, 2006 and August 1, 2006 heretofore executed and delivered by the Company to the Trustees under said Indenture of Mortgage or Deed of Trust dated October 1, 1941; said Indenture of Mortgage or Deed of Trust dated October 1, 1941, as amended by said Supplemental Indentures, being hereinafter sometimes referred to as the “Indenture”; and said U.S. Bank National Association and Richard Prokosch (successor Co-Trustee), of the City of Oakdale, Washington County, State of Minnesota, as Trustees, as such Trustees, being hereinafter sometimes referred to as the “Trustees” or the “Trustees under the Indenture”;

WITNESSETH:

WHEREAS, the Company has entered into a Credit Agreement, dated as of February 9, 2007 (as amended or otherwise modified from time to time, the “Credit Agreement”) by and among the Company, Central Illinois Light Company, Illinois Power Company, AmerenEnergy Resources Generating Company and CILCORP Inc., as borrowers, the lenders from time to time party thereto (the “Lenders”) and JPMorgan Chase Bank, N.A., as agent (in such capacity, the “Agent”) for the Lenders, providing for the making of certain financial accommodations thereunder to the Company, and pursuant to such Credit Agreement, the Company has agreed to issue to the Agent, as evidence of and security for the Obligations (as such term is defined in the Credit Agreement) of the Company (the “Company Obligations”), a new series of bonds under the Indenture;

WHEREAS, for such purposes, the Company has determined, by resolutions duly adopted by its Board of Directors, to issue bonds of an additional series under and to be secured by the Indenture, as hereby amended, to be known and designated as First Mortgage Bonds, 2007 Credit Agreement Series (hereinafter sometimes referred to as the “bonds of 2007 Credit Agreement Series” or the “bonds of said Series”), and the bonds of said Series shall be authorized, authenticated and issued only as registered bonds without coupons, and to execute

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 and deliver this supplemental indenture, pursuant to the provisions of Article I, as amended, Section 6 of Article II and Article XVI of the Indenture, for the purpose of (1) creating and authorizing not to exceed $135,000,000 aggregate principal amount of bonds of 2007 Credit Agreement Series and setting forth the form, terms, provisions and characteristics thereof, and (2) modifying or amending certain provisions of the Indenture in the particulars and to the extent hereinafter specifically provided; and

WHEREAS, the bonds of 2007 Credit Agreement Seriesshall be issued to the Agent as evidence of and security for the Company Obligations under the Credit Agreement;

WHEREAS, the execution and delivery by the Company of this supplemental indenture have been duly authorized by the Board of Directors of the Company; and the Company has requested, and hereby requests, the Trustees to enter into and join with the Company in the execution and delivery of this supplemental indenture; and

WHEREAS, the bonds of 2007 Credit Agreement Series are to be authorized, authenticated and issued only in the form of registered bonds without coupons, and the bonds of 2007 Credit Agreement Series and the certificate of the Trustee thereon shall be substantially in the following form, to wit:

[FORM OF BOND]

No. _______   $__________  

Illinois Commerce Commission

Identification No.: Ill. C.C. No. ____

Notwithstanding any provisions hereof or in the Indenture

this Bond is not assignable or transferable except to a successor Agent appointed in

accordance with the Credit Agreement, dated

as of February 9, 2007, hereinafter referred to.

Central Illinois Public Service Company

First Mortgage Bond, 2007 Credit Agreement Series

REGISTERED OWNER: JPMorgan Chase Bank, N.A.,

PRINCIPAL AMOUNT _______________________________ DOLLARS

CENTRAL ILLINOIS PUBLIC SERVICE COMPANY, an Illinois corporation (hereinafter referred to as the “Company”), for value received, hereby promises to pay to the Registered Owner specified above, as agent (in such capacity, the “Agent”) for the Lenders (as defined below) under the Credit Agreement, dated as of February 9, 2007, by and among the Company, Central Illinois Light Company, Illinois Power Company, AmerenEnergy Resources Generating Company and CILCORP Inc., as borrowers, the lenders from time to time party thereto (the “Lenders”) and JPMorgan Chase Bank, N.A., as agent (as amended or otherwise modified from time to time, the “Credit Agreement”), or registered assigns, the Principal Amount

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specified above or such lesser principal amount as shall be equal to the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company outstanding on the Maturity Date (having at any time the meaning such term has at such time under the Credit Agreement) of the Company, but not in excess of the Principal Amount of this bond, and to pay interest thereon at the Interest Rate (as defined below) until the principal hereof is paid or duly made available for payment on the Maturity Date or in the event of redemption of this bond, until the redemption date.

Interest on this bond shall be payable on each Interest Payment Date (as defined below), commencing on the first Interest Payment Date next succeeding the date of this bond. If the Maturity Date falls on a day which is not a Business Day, as defined below, principal and any interest and/or fees payable with respect to the Maturity Date will be paid on the next succeeding Business Day. The interest payable, and punctually paid or duly provided for, on any Interest Payment Date will, subject to certain exceptions provided in the Supplemental Indenture dated as of March 1, 2007, hereinafter referred to, be paid to the person in whose name this bond (or one or more predecessor bonds) is registered at the close of business on the Record Date (as defined below); provided, however, that interest payable on the Maturity Date will be payable to the person to whom the principal hereof shall be payable. Should the Company default in the payment of interest (“Defaulted Interest”), the Defaulted Interest shall be paid to the person in whose name this bond is registered on the Record Date to be established by the Trustee for payment of such Defaulted Interest. As used herein, (A) “Business Day” shall have the meaning assigned thereto in the Credit Agreement; (B) “Interest Payment Date” shall mean each date on which Company Obligations constituting interest and/or fees are due and payable from time to time pursuant to the Credit Agreement; (C) “Interest Rate” shall mean a rate of interest per annum, adjusted as necessary, to result in an interest payment equal to the aggregate amount of Company Obligations constituting interest and fees of the Company due under the Credit Agreement on the applicable Interest Payment Date; and (D) “Record Date” with respect to any Interest Payment Date shall mean the day (whether or not a Business Day) immediately next preceding such Interest Payment Date.

Both the principal of and the interest on this bond shall be payable in immediately available funds at the office or agency of the Trustee, in any coin or currency of the United States of America which at the time of payment is legal tender for public and private debts.

This bond is one of the bonds issued and to be issued from time to time under and in accordance with and all secured by the indenture of mortgage or deed of trust dated October 1, 1941, executed and delivered by the Company to U.S. Bank National Association (formerly U.S. Bank Trust National Association, formerly First Trust National Association, formerly First Trust of Illinois, National Association, successor trustee to Bank of America Illinois, formerly Continental Bank, formerly Continental Bank, National Association and formerly Continental Illinois National Bank and Trust Company of Chicago and hereinafter referred to as the “Trustee”) and Edmond B. Stofft, as Trustees, and the various indentures supplemental thereto, including the Supplemental Indenture pursuant to which $135,000,000 in aggregate principal amount of the First Mortgage Bonds, 2007 Credit Agreement Series (the “2007 Credit Agreement Series Bonds”) are authorized, each executed and delivered by the Company to the Trustees under said indenture of mortgage or deed of trust dated October 1, 1941, prior to the authentication of this bond (said indenture of mortgage or deed of trust and said supplemental

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 indentures being hereinafter referred to, collectively, as the “Indenture”); and said U.S. Bank National Association and Richard Prokosch (successor Co-Trustee), of the City of Oakdale, Washington County, State of Minnesota, as Trustees (successor Co-Trustee) being now the Trustees under the Indenture. Reference to the Indenture and to all supplemental indentures, if any, hereafter executed pursuant to the Indenture is hereby made for a description of the property mortgaged and pledged, the nature and extent of the security and the rights of the holders and Registered Owners of said bonds and of the Trustees and of the Company in respect of such security. By the terms of the Indenture the bonds to be secured thereby are issuable in series, which may vary as to date, amount, date of maturity, rate of interest, redemption provisions, medium of payment and in other respects as in the Indenture provided.

The 2007 Credit Agreement Series Bondsare to be issued and delivered to the Agent in order to evidence and secure the obligations of the Company under the Credit Agreement to make payments to the Lenders under the Credit Agreement and to provide the Lenders the benefit of the lien of the Indenture with respect to the 2007 Credit Agreement Series Bonds.

The obligation of the Company to make payments with respect to principal under the Credit Agreement shall not give rise to an obligation to pay principal of the 2007 Credit Agreement Series Bonds except on the Maturity Date of the Company or upon redemption hereof. If at any time any permanent reduction of the Borrower Sublimit (as defined in the Credit Agreement) of the Company or the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company shall result in the principal of the 2007 Credit Agreement Series Bonds being greater than the greater of the Borrower Sublimit and the Borrower Credit Exposure, a payment obligation with respect to the principal of the 2007 Credit Agreement Series Bonds in the amount of such excess shall be deemed discharged upon the effectiveness of such permanent reduction. No payment of principal under the Credit Agreement shall reduce the principal amount of the2007 Credit Agreement Series Bonds to an amount less than the greater of the Borrower Sublimit and the Borrower Credit Exposure.

The obligation of the Company to make payments with respect to the interest on the 2007Credit Agreement Series Bonds shall be fully or partially, as the case may be, satisfied and discharged to the extent that, at the time that any such payment shall be due, the then due interest and/or fees of the Company under the Credit Agreement shall have been fully or partially paid. Satisfaction of any obligation to the extent that payment is made with respect to the interest and/or fees of the Company under the Credit Agreement means that if any payment is made on the interest and/or fees of the Company under the Credit Agreement, a corresponding payment obligation with respect to the interest on the 2007 Credit Agreement Series Bonds shall be deemed discharged in the same amount as such payment made on the interest and/or fees of the Company under the Credit Agreement.

The Trustee may at any time and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of and interest on the 2007 Credit Agreement Series Bonds, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to the foregoing paragraphs unless and until the Trustee shall have received a written notice from the Agent stating (i) that timely payment of principal of or interest on the 2007 Credit Agreement Series Bonds has not been made, (ii) that the Company is

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in arrears as to the payments required to be made by it to the Agent in connection with the Company Obligations pursuant to the Credit Agreement, and (iii) the amount of the arrearage.

This bond is not redeemable except upon written demand of the Agent following the occurrence of a Default by the Company under the Credit Agreement and the acceleration of the Company Obligations, as provided under the Credit Agreement.

In case of certain events of default specified in the Indenture, the principal of this bond may be declared or may become due and payable in the manner and with the effect provided in the Indenture. No recourse shall be had for the payment of the principal of or interest on this bond, or for any claim based hereon, or otherwise in respect hereof or of the Indenture or any indenture supplemental thereto, to or against any incorporator, stockholder, officer or director, past, present or future, of the Company, or of any predecessor or successor corporation, either directly or through the Company, or such predecessor or successor corporation, under any constitution or statute or rule of law, or by the enforcement of any assessment, penalty, or otherwise, all such liability of incorporators, stockholders, directors and officers being waived and released by the Registered Owner hereof by the acceptance of this bond and being likewise waived and released by the terms of the Indenture.

This bond shall not be assignable or transferable except to a successor Agent appointed in accordance with the Credit Agreement. This bond is exchangeable by the Registered Owner hereof, in person or by attorney duly authorized, at the principal office or place of business of the Trustee under the Indenture, upon the surrender and cancellation of this bond and the payment of any stamp tax or other governmental charge, and upon any such exchange a new registered bond or bonds without coupons, of the same series and maturity and for the same aggregate principal amount, will be issued in exchange heretofore; provided, that the Company shall not be required to exchange any bonds of 2007 Credit Agreement Series for a period of ten (10) days next preceding an Interest Payment Date with respect to such bonds.

The Agent shall surrender this bond to the Trustee when each of the Borrower Sublimit and the Borrower Credit Exposure have been reduced to zero and all fees and other amounts payable by the Company pursuant to the Credit Agreement with respect to the Company Obligations shall have been duly paid.

This bond shall not be valid or become obligatory for any purpose unless and until it shall have been authenticated by the execution by the Trustee or its successor in trust under the Indenture of the Trustee’s Certificate endorsed hereon.

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IN WITNESS WHEREOF, Central Illinois Public Service Company has caused this bond to be executed in its name by the manual or facsimile signature of its President or one of its Vice-Presidents, and its corporate seal or a facsimile thereof to be affixed or imprinted hereon and attested by the manual or facsimile signature of its Secretary or one of its Assistant Secretaries.

	CENTRAL ILLINOIS PUBLIC SERVICE COMPANY By ______________________________ President
Attest: By_____________________________ Secretary

This bond is one of the bonds of the series designated therein, described in the within mentioned Indenture.

U.S. BANK NATIONAL ASSOCIATION, as

Trustee

By_______________________________

Authorized Officer

[END OF FORM OF BOND]

NOW, THEREFORE, in consideration of the premises and of the sum of One Dollar ($1.00) duly paid by the Trustees to the Company, and of other good and valuable considerations, the receipt whereof is hereby acknowledged, and for the purpose of further securing the due and punctual payment of the principal of and interest on all bonds which have been heretofore or shall be hereafter issued under the Indenture and indentures supplemental thereto and which shall be at any time outstanding thereunder and secured thereby and $135,000,000 aggregate principal amount of the bonds of 2007 Credit Agreement Series, and for the purpose of securing the faithful performance and observance of all the covenants and conditions set forth in the Indenture and/or in any indenture supplemental thereto, the Company has given, granted, bargained, sold, transferred, assigned, pledged, mortgaged, warranted the title to and conveyed, and by these presents does give, grant, bargain, sell, transfer, assign, pledge, mortgage, warrant the title to and convey unto U.S. Bank National Association and Richard Prokosch (successor Co-Trustee), of the City of Oakdale, Washington County, State of Minnesota, as Trustees, as Trustees under the Indenture as therein provided, and their successors in the trusts thereby created, and to their assigns, all the right, title and interest of the Company

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in and to any and all premises, plants, property, leases and leaseholds, franchises, permits, rights and powers, of every kind and description, real and personal, which have been acquired by the Company through construction, purchase, consolidation or merger, or otherwise, subsequent to January 1, 2006, and which are owned by the Company at the date of the execution hereof, together with the rents, issues, products and profits therefrom, excepting, however, and there is hereby expressly reserved and excluded from the lien and effect of the Indenture and of this supplemental indenture, all right, title and interest of the Company, now owned, in and to (a) all cash, bonds, shares of stock, obligations and other securities not deposited with the Trustee or Trustees under the Indenture, and (b) all accounts and bills receivable, judgments (other than for the recovery of real property or establishing a lien or charge thereon or right therein) and chooses in action not specifically assigned to and pledged with the Trustee or Trustees under the Indenture, and (c) all personal property acquired or manufactured by the Company for sale, lease, rental or consumption in the ordinary course of business, and (d) the last day of each of the demised terms created by any lease of property leased to the Company and under each and every renewal of any such lease, the last day of each and every such demised term being hereby expressly reserved to and by the Company, and (e) all gas, oil and other minerals now or hereafter existing upon, within or under any real estate of the Company subject to, or hereby subjected to, the lien of the Indenture.

And upon the considerations and for the purposes aforesaid, and in order to provide, pursuant to the terms of the Indenture, for the issuance under the Indenture, as hereby amended, of bonds of 2007 Credit Agreement Series and to fix the terms, provisions and characteristics of the bonds of 2007 Credit Agreement Series, and to modify or amend the Indenture in the particulars and to the extent hereinafter in this supplemental indenture specifically provided, the Company hereby covenants and agrees with the Trustees as follows:

Article I

Section 1.1A series of bonds issuable under the Indenture, as hereby amended, to be known and designated as “First Mortgage Bonds, 2007 Credit Agreement Series” and which shall be executed, authenticated and issued only in the form of registered bonds without coupons, is hereby created and authorized. The bonds of 2007 Credit Agreement Series and the Trustee’s Certificate to be endorsed thereon shall be substantially in the form thereof hereinbefore recited (the “Bond Form”). Each bond of 2007 Credit Agreement Series is to be issued and registered in the name of the Agent under the Credit Agreement to evidence and secure any and all Obligations (as such term is defined in the Credit Agreement) of the Company (the “Company Obligations”) under the Credit Agreement. Each bond of 2007 Credit Agreement Series shall be dated as of the Interest Payment Date (as defined below) thereof to which interest was paid next preceding the date of issue, unless (a) issued on an Interest Payment Date thereof to which interest was paid, in which event it shall be dated as of such issue date, or (b) issued prior to the occurrence of the first Interest Payment Date thereof to which interest was paid, in which event it shall be dated the date of original issuance.

The bonds of 2007 Credit Agreement Series shall be issued in the aggregate principal amount of not to exceed $135,000,000 and shall mature on the Maturity Date (having at any time the meaning such term has at such time under the Credit Agreement) of the Company. The principal amount of bonds of the 2007 Credit Agreement Series outstanding from time to time

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shall always be equal to the greater of (i) the Company’s Borrower Sublimit (as defined in the Credit Agreement, without giving effect to clause (ii) of such definition) and (ii) the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company on the Maturity Date, but not in excess of $135,000,000. Under the Credit Agreement, the Company must at any time it increases its Borrower Sublimit deliver additional bonds of the 2007 Credit Agreement Series in an amount such that the requirement of the preceding sentence is at that time satisfied. Upon submission of the appropriate certificates and opinions as required under the Indenture, the Company may so issue and the Trustee shall authenticate from time to time bonds of the 2007 Credit Agreement Series at any time on or prior to January 14, 2010.

The bonds of 2007 Credit Agreement Series shall bear interest from their date as set forth in the Bond Form. Interest on the bonds of 2007 Credit Agreement Series shall be payable on each Interest Payment Date (as defined below), commencing on the first Interest Payment Date next succeeding the date of the bonds of 2007 Credit Agreement Series. If the Maturity Date falls on a day which is not a Business Day, as defined below, principal and any interest and/or fees payable by the Company with respect to the Maturity Date will be paid on the next succeeding Business Day.

Both the principal of and the interest on the bonds of 2007 Credit Agreement Series shall be payable at the times and in the manner set forth in the form of bond set out herein and in immediately available funds at the office or agency of the Trustee, in any coin or currency of the United States of America which at the time of payment is legal tender for public and private debts.

Section 1.2Anything contained in Section 14 of Article I of the Indenture, or elsewhere in the Indenture, to the contrary notwithstanding, only the person in whose name bonds of 2007 Credit Agreement Series are registered (the “Registered Owner”) at the close of business on the Record Date (as defined below) 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 bonds upon any transfer or exchange subsequent to the Record Date and prior to such Interest Payment Date; provided, however, that if and to the extent the Company shall default in the payment of the interest due on such Interest Payment Date, such defaulted interest shall be paid to the persons in whose names outstanding bonds of 2007 Credit Agreement Series are registered on the Record Date to be established by the Trustee for payment of such defaulted interest.

The obligation of the Company to make payments with respect to principal under the Credit Agreement shall not give rise to an obligation to pay principal of the 2007 Credit Agreement Series Bonds except on the Maturity Date of the Company or upon redemption as provided in this Supplemental Indenture. If at any time any permanent reduction of the Borrower Sublimit (as defined in the Credit Agreement) of the Company or the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company shall result in the principal of the 2007 Credit Agreement Series Bonds being greater than the greater of the Borrower Sublimit and the Borrower Credit Exposure, a payment obligation with respect to the principal of the 2007 Credit Agreement Series Bonds in the amount of such excess shall be deemed discharged upon the effectiveness of such permanent reduction. No payment of principal under the Credit

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Agreement shall reduce the principal amount of the2007 Credit Agreement Series Bonds to an amount less than the greater of the Borrower Sublimit and the Borrower Credit Exposure.

The obligation of the Company to make payments with respect to the interest on the bonds of 2007 Credit Agreement Series shall be fully or partially, as the case may be, satisfied and discharged to the extent that, at the time that any such payment shall be due, the then due interest and/or fees of the Company under the Credit Agreement shall have been fully or partially paid. Satisfaction of any obligation to the extent that payment is made with respect to the interest and/or fees of the Company under the Credit Agreement means that if any payment is made on the interest and/or fees of the Company under the Credit Agreement, a corresponding payment obligation with respect to the interest on the bonds of 2007 Credit Agreement Series shall be deemed discharged in the same amount as such payment made on the interest and/or fees of the Company under the Credit Agreement.

The Trustee may at any time and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of and interest on the bonds of 2007 Credit Agreement Series, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to the foregoing paragraphs unless and until the Trustee shall have received a written notice from the Agent stating (i) that timely payment of principal of or interest on the bonds of 2007 Credit Agreement Series has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the Agent in connection with the Company Obligations pursuant to the Credit Agreement, and (iii) the amount of the arrearage.

Section 1.3As used herein, (A) “Business Day” shall have the meaning assigned thereto in the Credit Agreement; (B) “Interest Payment Date” shall mean each date on which Company Obligations constituting interest and/or fees are due and payable from time to time pursuant to the Credit Agreement; (C) “Interest Rate” shall mean a rate of interest per annum, adjusted as necessary, to result in an interest payment equal to the aggregate amount of Company Obligations constituting interest and fees of the Company due under the Credit Agreement on the applicable Interest Payment Date; and (D) “Record Date” with respect to any Interest Payment Date shall mean the day (whether or not a Business Day) immediately next preceding such Interest Payment Date.

Section 1.4Except as set forth herein, the bonds of 2007 Credit Agreement Series are not redeemable. Upon the occurrence of a Default by the Company under the Credit Agreement and the acceleration of the Company Obligations, the bonds of 2007 Credit Agreement Series shall be redeemable in whole upon receipt by the Trustee of a written demand from the Agent stating that there has occurred under the Credit Agreement both a Default by the Company and a declaration of acceleration of the Company Obligations and demanding redemption of the bonds of 2007 Credit Agreement Series (including a description of the amount of principal, interest, fees, cash collateralization obligations and other amounts which comprise such Company Obligations). The Company waives any right it may have to prior notice of such redemption under the Indenture and any other notice required under the Indenture, including notice to be given by the Company, shall be deemed satisfied by the notice given by the Agent as aforesaid. Upon surrender of the bonds of 2007 Credit Agreement Series by the Agent to the Trustee, the bonds of 2007 Credit Agreement Series shall be redeemed at a redemption price equal to the aggregate amount of the Company Obligations.

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Section 1.5The bonds of 2007 Credit Agreement Series shall not be assignable or transferable except to a successor Agent appointed in accordance with the Credit Agreement. The bonds of 2007 Credit Agreement Seriesare exchangeable by the Registered Owner thereof, in person or by attorney duly authorized, at the principal office or place of business of the Trustee under the Indenture, upon the surrender and cancellation of said bonds and the payment of any stamp tax or other governmental charge, and upon any such exchange a new registered bond or bonds without coupons, of the same series and maturity and for the same aggregate principal amount, will be issued in exchange theretofore; provided, that the Company shall not be required to exchange any bonds of 2007 Credit Agreement Series for a period of ten (10) days next preceding an Interest Payment Date with respect to such bonds.

Section 1.6The bonds of 2007 Credit AgreementSeries shall, from time to time, be executed on behalf of the Company and sealed with the corporate seal of the Company, all in the manner provided or permitted by Section 6 of Article I of the Indenture, as follows:

(a)bonds of 2007 Credit Agreement Series executed on behalf of the Company by its President or a Vice-President and/or by its Secretary or an Assistant Secretary may be so executed by the facsimile signature of such President or Vice-President and/or of such Secretary or Assistant Secretary, as the case may be, of the Company, or of any person or persons who shall have been such officer or officers, as the case may be, of the Company on or subsequent to the date of this supplemental indenture, notwithstanding that he or they may have ceased to be such officer or officers of the Company at the time of the actual execution, authentication, issue or delivery of any of such bonds, and any such facsimile signature or signatures of any such officer or officers on any such bonds shall constitute execution of such bonds on behalf of the Company by such officer or officers of the Company for the purposes of the Indenture, as hereby amended, and shall be valid and effective for all purposes, provided that all bonds shall always be executed on behalf of the Company by the signature, manual or facsimile, of its President or a Vice-President and of its Secretary or an Assistant Secretary, and provided, further, that none of such bonds shall be executed on behalf of the Company by the same officer or person acting in more than one capacity; and

(b)such corporate seal of the Company may be a facsimile, and any bonds of 2007 Credit Agreement Series on which such facsimile seal shall be affixed, impressed, imprinted or reproduced shall be deemed to be sealed with the corporate seal of the Company for the purposes of the Indenture, as hereby amended, and such facsimile seal shall be valid and effective for all purposes.

Section 1.7As provided in Section 8.4 of the Credit Agreement, the Agent shall surrender the bonds of 2007 Credit Agreement Series to the Trustee for cancellation when each of the Borrower Sublimit and the Borrower Credit Exposure have been reduced to zero and all fees and other amounts payable by the Company pursuant to the Credit Agreement with respect to the Company Obligations shall have been duly paid.

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Article II

Section 2.1Sections 10 and 16 of Article III of the Indenture are, and each of them is, hereby amended by striking out the words “Series 1997-2, Senior Notes Series AA-1, Senior Notes Series AA-2, Senior Notes Series BB, Environmental Improvement Series 2004, Senior Notes Series CC and 2006 Credit Agreement Series” wherever the same occur in each of said sections, and by inserting, in lieu thereof, the words “Series 1997-2, Senior Notes Series AA-1, Senior Notes Series AA-2, Senior Notes Series BB, Environmental Improvement Series 2004, Senior Notes Series CC, 2006 Credit Agreement Series and 2007 Credit Agreement Series” and the Company hereby covenants and agrees to observe and comply with the provisions of said sections as hereby amended.

Article III

Section 3.1The provisions of this supplemental indenture shall become and be effective from and after the execution hereof, and the Indenture, as hereby amended, shall remain in full force and effect.

Section 3.2Each reference in the Indenture, or in this supplemental indenture, to any article, section, term or provision of the Indenture shall mean and be deemed to refer to such article, section, term or provision of the Indenture, as hereby amended, except where the context otherwise indicates.

Section 3.3All the covenants, provisions, stipulations and agreements in this supplemental indenture contained are and shall be for the sole and exclusive benefit of the parties hereto, their successors and assigns, and of the holders and Registered Owners from time to time of the bonds of 2007 Credit Agreement Series and of the coupons issued and outstanding from time to time under and secured by the Indenture, as hereby amended, and the Agent, for the benefit of the Lenders under the Credit Agreement.

This supplemental indenture has been executed in a number of identical counterparts, each of which so executed shall be deemed to be an original.

At the time of the execution of this supplemental indenture, the aggregate principal amount of all indebtedness of the Company outstanding, or to be presently outstanding, under and secured by the Indenture, as hereby amended, is $496,500,000, evidenced by First Mortgage Bonds of the series listed below, issued by the Company under said Indenture and now outstanding or to be presently issued by it under said Indenture, as follows:

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Series	Interest Rate (%)	Maturity Date	Principal                         Amount ($)
1997-2	7.61	June 1, 2017	40,000,000
Senior Notes AA-1	5.375	December 15, 2008	15,000,000
Senior Notes AA-2	6.125%	December 15, 2028	60,000,000
Senior Notes BB	6.625%	June 15, 2011	150,000,000
Series 2004	*	July 1, 2025	35,000,000
Senior Notes CC	6.70%	June 15, 2036	61,500,000
2006 Credit Agreement	**	**	135,000,000
2007 Credit Agreement	***	***	0(a)
		Total........	496,500,000

Section 3.4The Company acknowledges and intends that all advances made to it by the Lenders under the Credit Agreement, including future advances whenever hereafter made, shall be a lien from the time this Supplemental Indenture is recorded, as provided in Section 15-1302(b)(1) of the Illinois Mortgage Foreclosure Law (the “Act”), 735 ILCS 15-1101, et seq. The amount of the bonds of the 2007 Credit Agreement Series which comprises the principal amount then outstanding of the Obligations under the Credit Agreement constitutes revolving credit indebtedness secured by a mortgage on real property, pursuant to the terms and conditions of 205 ILCS 5/5d from the date of this Supplemental Indenture.

^* As determined in accordance with the Indenture of Trust dated as of October 1, 2004 between the Illinois Finance Authority and UMB Bank, N.A., as Trustee.

** As determined in accordance with the Credit Agreement dated as of July 14, 2006 among the Company and the other Borrowers identified therein and JPMorgan Chase, N.A. as agent.

*** As determined in accordance with the Credit Agreement.

(a) To be issued by the Company under said Indenture from time to time under this Supplemental Indenture in the amounts as provided in the Credit Agreement but only upon surrender of an equal amount of bonds of the 2006 Credit Agreement Series.

In WITNESS WHEREOF, said Central Illinois Public Service Company has caused this instrument to be executed in its corporate name by its President or a Vice President and its corporate seal or a facsimile thereof to be hereunto affixed and to be attested by its Secretary or an Assistant Secretary, and said U.S. Bank National Association, for the purpose of entering into and joining with the Company in the execution of this supplemental indenture, has caused this instrument to be executed in its corporate name by one of its Vice Presidents and its corporate seal to be hereunto affixed and to be attested by one of its Assistant Vice Presidents, and said Richard Prokosch, for the purpose of entering into and joining with the Company in the execution of this supplemental indenture, has signed and sealed this instrument; all as of the day and year first above written.

	Central Illinois Public Service Company By        /s/ Jerre E. Birdsong                        Name: Jerre E. Birdsong Title: Vice President and Treasurer
(Corporate Seal) Attest: By:      /s/ G.L. Waters              Name: G.L.Waters Title: Assistant Secretary

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	U.S. Bank National Association By:      /s/ Richard Prokosch                Name: Richard Prokosch Title:   Vice President
(Corporate Seal) Attest: By:       /s/ Darlene Garsteig         Name: Darlene Garsteig Title:Assistant Vice President
	By:          /s/ Richard Prokosch (Seal) Richard Prokosch

State of Missouri  )

)SS

City of St. Louis   )

I, Carol A. Head, a Notary Public, do hereby certify that Jerre E. Birdsong, Vice President and Treasurer of Central Illinois Public Service Company, a corporation organized and existing under the laws of the State of Illinois, and G.L. Waters, Assistant Secretary of said corporation, who are both personally known to me to be the same persons whose names are subscribed to the foregoing instrument as such officers, respectively, of said corporation, and who are both personally known to me to be such officers, appeared before me this day in person and severally acknowledged that they signed, sealed and delivered said instrument as their free and voluntary act as such officers, and as the free and voluntary act of said corporation, for the uses and purposes therein set forth.

Given under my hand and official seal this 5th day of March 2007, in the City and State aforesaid.

	/s/ Carol A. Head
	Carol A. Head Notary Public
(Notarial Seal)

My commission expires 11-20-2010

State of Minnesota  )

)SS

County of Ramsey   )

I, L. Elaine Eby, a Notary Public in and for Ramsey County in the State aforesaid, do hereby certify that:

(a) Richard Prokosch, a Vice President of U.S. Bank National Association, a national banking association, and Darlene Garsteig, an Assistant Vice President of said association, who are both personally known to me to be the same persons whose names are subscribed to the foregoing instrument as such officers, respectively, of said association, and who are both personally known to me to be such officers, appeared before me this day in person and severally acknowledged that they signed, sealed and delivered said instrument as their free and voluntary act as such officers, and as the free and voluntary act of said association, for the uses and purposes therein set forth; and

(b) Richard Prokosch, personally known to me to be the same person whose name is subscribed to the foregoing instrument, appeared before me this day in person and acknowledged that he signed, sealed and delivered said instrument as his free and voluntary act, for the uses and purposes therein set forth.

Given under my hand and official seal this 5th day of March, 2007.

	/s/ L. Elaine Eby L. Elaine Eby Notary Public
(Notarial Seal)

My Commission expires: January 31, 2010

EX-4.4

Exhibit 4.4

When recorded mail to:

Craig W. Stensland

Central Illinois Light Company

One Ameren Plaza (MC 1310)

1901 Chouteau Avenue

St. Louis, MO 63103

Indenture

Between

Central Illinois Light Company

and

Deutsche Bank Trust Company Americas,

as successor Trustee under Indenture of Mortgage and Deed of Trust, dated as of April 1, 1933, between Illinois Power Company and Bankers Trust Company (predecessor of Deutsche Bank Trust Company Americas), as Trustee, as amended and supplemented by Indenture between the same parties, dated as of June 30, 1933, and as amended, supplemented and assumed by Indenture dated as of July 1, 1933, between Central Illinois Light Company and Bankers Trust Company (predecessor of Deutsche Bank Trust Company Americas), as Trustee, and as amended and supplemented by various Indentures between the same parties bearing subsequent dates.

Dated as of March 1, 2007

This instrument was prepared by Steven R. Sullivan, Senior Vice President, General Counsel and

Secretary of Central Illinois Light Company, 300 Liberty Street, Peoria, Illinois 61602, (314) 554-2098.

Indenture dated as of the 1^st day of March, 2007 (hereinafter sometimes referred to as this “Supplemental Indenture”), between Central Illinois Light Company, a corporation of the State of Illinois (hereinafter sometimes referred to as the “Company”), party of the first part, and Deutsche Bank Trust Company Americas, a corporation of the State of New York, as successor Trustee (hereinafter sometimes referred to as the “Trustee”), party of the second part, under the Indenture of Mortgage and Deed of Trust between Illinois Power Company and Bankers Trust Company (predecessor of Deutsche Bank Trust Company Americas), as Trustee, dated as of April 1, 1933, as amended and supplemented by Indenture between said Illinois Power Company and said Bankers Trust Company (predecessor of Deutsche Bank Trust Company Americas), dated as of June 30, 1933, and as amended, supplemented and assumed by Indenture between the Company and said Bankers Trust Company (predecessor of Deutsche Bank Trust Company Americas), dated as of July 1, 1933, and as amended and supplemented by various Indentures between the Company and said Bankers Trust Company (predecessor of Deutsche Bank Trust Company Americas) bearing subsequent dates (said Indenture of Mortgage and Deed of Trust as amended, supplemented and assumed being hereinafter sometimes referred to as the “Indenture”).

WHEREAS, the Indenture provides for the issuance of bonds thereunder in one or more series, the form of which series of bonds to be substantially in the form set forth therein with such insertions, omissions and variations as the Board of Directors of the Company may determine; and

WHEREAS, the Company has entered into a Credit Agreement, dated as of February 9, 2007 (as amended or otherwise modified from time to time, the “Credit Agreement”) by and among the Company, Central Illinois Public Service Company, Illinois Power Company, AmerenEnergy Resources Generating Company and CILCORP Inc., as borrowers, the lenders from time to time party thereto (the “Lenders”) and JPMorgan Chase Bank, N.A., as agent (in such capacity, the “Agent”) for the Lenders, providing for the making of certain financial accommodations thereunder to the Company, and pursuant to such Credit Agreement, the Company has agreed to issue to the Agent, as evidence of and security for the Obligations (as such term is defined in the Credit Agreement) of the Company (the “Company Obligations”), a new series of bonds under the Indenture; and

WHEREAS, for such purposes, the Company, by appropriate corporate action in conformity with the terms of the Indenture, has duly determined to create a series of bonds under the Indenture to be designated as “First Mortgage Bonds, 2007 Credit Agreement Series” (hereinafter sometimes referred to as the “bonds of the 2007 Credit Agreement Series”), the bonds of which series are to be issued as registered bonds without coupons and are to bear interest as specified in the form of bond of the 2007 Credit Agreement Series set forth below and are to mature, subject to prior acceleration and redemption, on the Maturity Date (as such term is defined in the Credit Agreement); and

WHEREAS, the bonds of 2007 Credit Agreement Series shall be issued to the Agent as evidence of and security for the Company Obligations under the Credit Agreement; and

WHEREAS, the definitive registered bonds without coupons of the 2007 Credit Agreement Series (certain of the provisions of which may be printed on the reverse side thereof)

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and the Trustee’s certificate of authentication to be borne by such bonds are to be substantially in the following forms, respectively:

[General Form of Registered Bond of the 2007 Credit Agreement Series]

No. ____ $________

_______________

Notwithstanding any provisions hereof or in the Indenture this Bond is not assignable or transferable except to a successor Agent appointed in accordance with the Credit Agreement, dated as of February 9, 2007, hereinafter referred to.

CENTRAL ILLINOIS LIGHT COMPANY

First Mortgage Bond, 2007 Credit Agreement Series

Illinois Commerce Commission

Identification No.: Ill. C.C. [____]

Central Illinois Light Company, a corporation of the State of Illinois (hereinafter called the “Company”), for value received, hereby promises to pay to JPMorgan Chase Bank, N.A., as agent (in such capacity, the “Agent”) for the Lenders (as defined below) under the Credit Agreement, dated as of February 9, 2007, by and among the Company, Central Illinois Public Service Company, Illinois Power Company, AmerenEnergy Resources Generating Company and CILCORP Inc., as borrowers, the lenders from time to time party thereto (the “Lenders”) and JPMorgan Chase Bank, N.A., as agent (as amended or otherwise modified from time to time, the “Credit Agreement”), or registered assigns, the principal amount specified above or such lesser principal amount as shall be equal to the amount of the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company outstanding on the Maturity Date (having at any time the meaning such term has at such time under the Credit Agreement) of the Company, but not in excess of the principal amount of this bond, and to pay interest thereon at the Interest Rate (as defined below) until the principal hereof is paid or duly made available for payment on the Maturity Date or in the event of redemption of this bond, until the redemption date.

Interest on this bond shall be payable on each Interest Payment Date (as defined below), commencing on the first Interest Payment Date next succeeding the date of this bond. If the Maturity Date falls on a day which is not a Business Day, as defined below, principal and any interest and/or fees payable with respect to the Maturity Date will be paid on the next succeeding Business Day. The interest payable, and punctually paid or duly provided for, on any Interest Payment Date will, subject to certain exceptions provided in the Supplemental Indenture dated as of March 1, 2007, hereinafter referred to, be paid to the person in whose name this bond (or one or more predecessor bonds) is registered at the close of business on the Record Date (as defined below); provided, however, that interest payable on the Maturity Date will be payable to the person to whom the principal hereof shall be payable. Should the Company default in the payment of interest (“Defaulted Interest”), the Defaulted Interest shall be paid to the person in whose name this bond is registered on the Record Date to be established by the Trustee for

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payment of such Defaulted Interest. As used herein, (A) “Business Day” shall have the meaning assigned thereto in the Credit Agreement; (B) “Interest Payment Date” shall mean each date on which Company Obligations constituting interest and/or fees are due and payable from time to time pursuant to the Credit Agreement; (C) “Interest Rate” shall mean a rate of interest per annum, adjusted as necessary, to result in an interest payment equal to the aggregate amount of Company Obligations constituting interest and fees of the Company due under the Credit Agreement on the applicable Interest Payment Date; and (D) “Record Date” with respect to any Interest Payment Date shall mean the day (whether or not a Business Day) immediately next preceding such Interest Payment Date.

Both the principal of and the interest on this bond shall be payable, in immediately available funds, at the office of the Trustee hereinafter referred to.

This bond is to be issued and delivered to the Agent in order to evidence and secure the obligations of the Company under the Credit Agreement to make payments to the Lenders under the Credit Agreement and to provide the Lenders the benefit of the lien of the Indenture with respect to the 2007 Credit Agreement Series Bonds.

The obligation of the Company to make payments with respect to principal under the Credit Agreement shall not give rise to an obligation to pay principal of the 2007 Credit Agreement Series Bonds except on the Maturity Date of the Company or upon redemption hereof. If at any time any permanent reduction of the Borrower Sublimit (as defined in the Credit Agreement) of the Company or the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company shall result in the principal of the 2007 Credit Agreement Series Bonds being greater than the greater of the Borrower Sublimit and the Borrower Credit Exposure, a payment obligation with respect to the principal of the 2007 Credit Agreement Series Bonds in the amount of such excess shall be deemed discharged upon the effectiveness of such permanent reduction. No payment of principal under the Credit Agreement shall reduce the principal amount of the2007 Credit Agreement Series Bonds to an amount less than the greater of the Borrower Sublimit and the Borrower Credit Exposure.

The obligation of the Company to make payments with respect to the interest on this bond shall be fully or partially, as the case may be, satisfied and discharged to the extent that, at the time that any such payment shall be due, the then due interest and/or fees of the Company under the Credit Agreement shall have been fully or partially paid. Satisfaction of any obligation to the extent that payment is made with respect to the interest and/or fees of the Company under the Credit Agreement means that if any payment is made on the interest and/or fees of the Company under the Credit Agreement, a corresponding payment obligation with respect to the interest on this bond shall be deemed discharged in the same amount as such payment made on the interest and/or fees of the Company under the Credit Agreement.

The Trustee may at any time and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of and interest on this bond, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to the foregoing paragraphs unless and until the Trustee shall have received a written notice from the Agent stating (i) that timely payment of principal of or interest on this bond has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the

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Agent in connection with the Company Obligations pursuant to the Credit Agreement, and (iii) the amount of the arrearage.

This bond is one of an issue of bonds of the Company, issuable in series, and is one of a series known as its First Mortgage Bonds of the series designated in its title, 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 (defined below) for the bonds of any particular series) by an Indenture of Mortgage and Deed of Trust dated as of April 1, 1933, executed by Illinois Power Company to Bankers Trust Company (predecessor of Deutsche Bank Trust Company Americas) or its successor (hereinafter sometimes referred to as the “Trustee”) as Trustee, as amended by Indenture dated as of June 30, 1933, as assumed by the Company and as amended and supplemented by Indentures between the Company and the Trustee bearing subsequent dates, including the Indenture dated as of March 1, 2007 (all of which indentures are herein collectively called the “Mortgage”), to which 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.

As more fully described in the supplemental indenture establishing the terms and provisions of the bonds of this series, the rights and obligations of the Company and the rights of the bondholders may be modified with the consent of the holders of not less than 60% in principal amount of the bonds adversely affected; provided, however, that no modification shall (1) extend the time, or reduce the amount, of any payment on any bond, without the consent of the holder of each bond so affected, (2) permit the creation of any lien, not otherwise permitted, prior to or on a parity with the lien of the Mortgage, without the consent of the holders of all bonds then outstanding, or (3) reduce the above percentage of the principal amount of bonds the holders of which are required to approve any such modification without the consent of the holders of all bonds then outstanding.

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 in the Mortgage provided.

This bond is not redeemable except upon written demand of the Agent following the occurrence of a Default by the Company under the Credit Agreement and the acceleration of the Company Obligations under the Credit Agreement.

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 fully registered bonds of other authorized denominations of the same series, upon presentation and surrender thereof, for cancellation, to the Trustee at its principal office in the Borough of Manhattan, The City of New York, New York.

This bond shall not be assignable or transferable except to a successor Agent appointed in accordance with the Credit Agreement. Subject to the restriction on transfer of this bond hereinbefore set forth, 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

5

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 therefor as provided in the Mortgage, and upon payment, if the Company shall require it, of the charges therein prescribed; provided, that the Company shall not be required to exchange any bonds of this series for a period of ten (10) days next preceding an Interest Payment Date with respect to such bonds.

The Agent shall surrender this bond to the Trustee when each of the Borrower Sublimit and the Borrower Credit Exposure of the Company have been reduced to zero and all fees and other amounts payable by the Company pursuant to the Credit Agreement with respect to the Company Obligations shall have been duly paid.

No recourse shall be had for the payment of the principal of or interest on this bond against any incorporator or any past, present or future subscriber to the capital stock, stockholder, officer 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.

This bond shall not become obligatory until Deutsche Bank Trust Company Americas, the Trustee under the Mortgage, or its successor thereunder, shall have signed the form of certificate endorsed hereon.

IN WITNESS WHEREOF, Central Illinois Light Company has caused this bond to be signed in its name by its President or a Vice President by a facsimile of his signature and a facsimile of its corporate seal to be printed hereon, attested by its Secretary or an Assistant Secretary by a facsimile of his signature.

Dated:
[Seal]	Central Illinois Light Company
	By__________________________________ [President]
Attest: ____________________________________ [Secretary]

6

[Form of Trustee’s Certificate]

This bond is one of the bonds of the series designated therein, described in the within-mentioned Mortgage.

Deutsche Bank Trust Company Americas,

as Trustee

By  Deutsche Bank National Trust Company

By__________________________________

Authorized Officer

and

WHEREAS, all things necessary to make the bonds of the 2007 Credit Agreement 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 have in all respects been duly authorized;

WHEREAS, the Company and the Trustee deem it advisable to enter into this Supplemental Indenture for the purpose of describing the bonds of the 2007 Credit Agreement Series, and of providing the terms and conditions of redemption thereof;

WHEREAS, the Company has reserved the right, without the consent or other action by the holders of the bonds of each series that is outstanding as of the date hereof, to amend the Indenture to add a new Section 115A thereto as provided for herein; and

WHEREAS, the Company by appropriate corporate action in conformity with the terms of the Indenture has elected to exercise such right to so amend the Indenture;

NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH: That Central Illinois Light Company, in consideration of the premises and of one dollar to it duly paid by the Trustee at or before the unsealing 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 both of the principal 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 of the Indenture 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 Deutsche Bank Trust Company Americas, as Trustee, and to its successor or successors in said trust, and to it and their assigns forever, all the properties of the Company located in the State of Illinois described on pages 13 and 14 under the heading DETAILED DESCRIPTION OF ADDITIONAL PROPERTIES which is made a part hereof.

And all other property real, personal and mixed, tangible and intangible of the character described in the granting clauses of the aforesaid Indenture of Mortgage and Deed of Trust dated

7

as of April 1, 1933 or in any indenture supplemental thereto acquired by the Company on or after the date of the execution and delivery of said Indenture of Mortgage and Deed of Trust (except any in said Indenture of Mortgage and Deed of Trust or in any indenture supplemental thereto expressly excepted) now owned or hereafter acquired by the Company and wheresoever situated.

Together with all and singular the tenements, hereditaments and appurtenances belonging or in any wise appertaining to the aforesaid property or any part thereof, with the reversion and reversions, remainder and remainders and (subject to the provisions of Article XI of the Indenture) the tolls, rents, revenues, issues, earnings, income, product and profits thereof, and all the estate, right, title and 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.

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 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, if any, 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. The bonds of the 2007 Credit Agreement Series shall mature, subject to prior acceleration and redemption, on the Maturity Date (having at any time the meaning such term has at such time under the Credit Agreement) of the Company, shall bear interest from their date as set forth in the form of bond hereinbefore set forth, and shall be designated as the Company’s First Mortgage Bonds of the series hereinbefore set forth. Both principal of and interest on the bonds shall be payable in lawful money of the United States of America at the office of the Trustee hereinafter mentioned. Each bond of 2007 Credit Agreement Series shall be dated as of

8

the Interest Payment Date (as defined below) thereof to which interest was paid next preceding the date of issue, unless (a) issued on an Interest Payment Date thereof to which interest was paid, in which event it shall be dated as of such issue date, or (b) issued prior to the occurrence of the first Interest Payment Date thereof to which interest was paid, in which event it shall be dated the date of original issuance.

Definitive bonds of the 2007 Credit Agreement Series will be issued, originally or otherwise, only as registered bonds without coupons in the name of the Agent as evidence of and security for the Company Obligations under the Credit Agreement; and they and the Trustee’s certificate of authentication shall be substantially in the forms hereinbefore recited, respectively.

The bonds of the 2007 Credit Agreement Series shall not be assignable or transferable except to a successor Agent appointed in accordance with the Credit Agreement. Subject to the restriction on transfer of the bonds of the 2007 Credit Agreement Series hereinbefore set forth, and in the manner and upon payment of the charges prescribed in the Indenture, registered bonds without coupons of the 2007 Credit Agreement Series may be exchanged for a like aggregate principal amount of fully registered bonds of other authorized denominations of the same series, upon presentation and surrender thereof for cancellation, to the Trustee at its principal office in the Borough of Manhattan, The City of New York, New York; provided, that the Company shall not be required to exchange any bonds of the 2007 Credit Agreement Series for a period of ten (10) days next preceding an Interest Payment Date with respect to such bonds. However, notwithstanding the provisions of Section 14 of the Indenture, no charge shall be made upon any transfer or exchange of bonds of said series other than for any tax or taxes or other governmental charge required to be paid by the Company.

Except as set forth herein, the bonds of the 2007 Credit Agreement Series are not redeemable. Upon the occurrence of a Default by the Company under the Credit Agreement and the acceleration of the Company Obligations, the bonds of the 2007 Credit Agreement Series shall be redeemable in whole upon receipt by the Trustee of a written demand from the Agent stating that there has occurred under the Credit Agreement both a Default by the Company and a declaration of acceleration of the Company Obligations and demanding redemption of the bonds of 2007 Credit Agreement Series (including a description of the amount of principal, interest, fees, cash collateralization obligations and other amounts which comprise such Company Obligations). The Company waives any right it may have to prior notice of such redemption under the Indenture and any other notice required under the Indenture, including notice to be given by the Company, shall be deemed satisfied by the notice given by the Agent as aforesaid. Upon surrender of the bonds of the 2007 Credit Agreement Series by the Agent to the Trustee, the bonds of 2007 Credit Agreement Series shall be redeemed at a redemption price equal to the aggregate amount of the Company Obligations.

Section 2. The principal amount of bonds of the 2007 Credit Agreement Series outstanding from time to time shall always be equal to the greater of (i) the Company’s Borrower Sublimit (as defined in the Credit Agreement, without giving effect to clause (ii) of such definition) and (ii) the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company on the Maturity Date, but not in excess of $150,000,000. Under the Credit Agreement, the Company must at any time it increases its Borrower Sublimit deliver additional bonds of the 2007 Credit Agreement Series in an amount such that the requirement of the preceding sentence

9

is at that time satisfied. Upon submission of the appropriate certificates and opinions as required under the Indenture, the Company may so issue and the Trustee shall authenticate from time to time bonds of the 2007 Credit Agreement Series at any time on or prior to January 14, 2010.

The obligation of the Company to make payments with respect to principal under the Credit Agreement shall not give rise to an obligation to pay principal of the 2007 Credit Agreement Series Bonds except on the Maturity Date of the Company or upon redemption as provided in this Supplemental Indenture. If at any time any permanent reduction of the Borrower Sublimit of the Company or the Borrower Credit Exposure of the Company shall result in the principal of the 2007 Credit Agreement Series Bonds being greater than the greater of the Borrower Sublimit and the Borrower Credit Exposure, a payment obligation with respect to the principal of the 2007 Credit Agreement Series Bonds in the amount of such excess shall be deemed discharged upon the effectiveness of such permanent reduction. No payment of principal under the Credit Agreement shall reduce the principal amount of the2007 Credit Agreement Series Bonds to an amount less than the greater of the Borrower Sublimit and the Borrower Credit Exposure.

The obligation of the Company to make payments with respect to the interest on the bonds of 2007 Credit Agreement Series shall be fully or partially, as the case may be, satisfied and discharged to the extent that, at the time that any such payment shall be due, the then due interest and/or fees of the Company under the Credit Agreement shall have been fully or partially paid. Satisfaction of any obligation to the extent that payment is made with respect to the interest and/or fees of the Company under the Credit Agreement means that if any payment is made on the interest and/or fees of the Company under the Credit Agreement, a corresponding payment obligation with respect to the interest on the bonds of 2007 Credit Agreement Series shall be deemed discharged in the same amount as such payment made on the interest and/or fees of the Company under the Credit Agreement.

The Trustee may at any time and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of and interest on the bonds of 2007 Credit Agreement Series, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to the foregoing paragraphs unless and until the Trustee shall have received a written notice from the Agent stating (i) that timely payment of principal of or interest on the bonds of 2007 Credit Agreement Series has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the Agent in connection with the Company Obligations pursuant to the Credit Agreement, and (iii) the amount of the arrearage.

As used herein, (A) “Business Day” shall have the meaning assigned thereto in the Credit Agreement; (B) “Interest Payment Date” shall mean each date on which Company Obligations constituting interest and/or fees are due and payable from time to time pursuant to the Credit Agreement; (C) “Interest Rate” shall mean a rate of interest per annum, adjusted as necessary, to result in an interest payment equal to the aggregate amount of Company Obligations constituting interest and fees of the Company due under the Credit Agreement on the applicable Interest Payment Date; and (D) “Record Date” with respect to any Interest Payment Date shall mean the day (whether or not a Business Day) immediately next preceding such Interest Payment Date.

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At any time that a bond of the 2007 Credit Agreement Series is surrendered to the Trustee other than in connection with the redemption thereof, in connection with the Trustee’s enforcement of rights after a completed default under the Mortgage or in connection with the exchange of that bond as provided in Section 1 hereof, such bond shall be cancelled by the Trustee and shall be treated for all intents and purposes as if it has never been issued. In the event that only a portion of a bond of the 2007 Credit Agreement Series is so surrendered, the Trustee shall deliver without charge to the Agent a new bond of the 2007 Credit Agreement Series in an aggregate principal amount equal to the difference between the principal amount of the portion of the bond of the 2007 Credit Agreement Series so surrendered and the principal amount of such bond prior to such surrender.

As provided in Section 8.4 of the Credit Agreement, the Agent shall surrender the bonds of 2007 Credit Agreement Series to the Trustee for cancellation when each of the Borrower Sublimit and the Borrower Credit Exposure of the Company have been reduced to zero and all fees and other amounts payable by the Company pursuant to the Credit Agreement with respect to the Company Obligations shall have been duly paid.

Section 3. Pursuant to the right retained by the Company in each supplemental indenture pursuant to which all bonds outstanding as of the date hereof were issued, the Indenture is hereby amended by inserting the following language as Section 115A immediately following current Section 115 of the Indenture:

“Section 115A. With the consent of the holders of not less than sixty per centum (60%) in principal amount of the bonds at the time outstanding or their attorneys-in-fact duly authorized, or, if the rights of the holders of one or more, but not all, series then outstanding are affected, the consent of the holders of not less than sixty per centum (60%) in aggregate principal amount of the bonds at the time outstanding of all affected series, taken together, and not any other series, the Company, when authorized by a resolution, and the Trustee may from time to time and at any time enter into an indenture or indentures supplemental hereto for the purpose of adding any provisions to or changing in any manner or eliminating any of the provisions of this Indenture or of any supplemental indenture or modifying the rights and obligations of the Company and the rights of the holders of any of the bonds and coupons; provided, however, that no such supplemental indenture shall (1) extend the maturity of any of the bonds or reduce the rate or extend the time of payment of interest thereon, or reduce the amount of the principal thereof, or reduce any premium, payable on the redemption thereof or change the coin or currency in which any bond or interest thereon is payable, without the consent of the holder of each bond so affected, or (2) permit the creation of any lien, not otherwise permitted, prior to or on a parity with the lien of this Indenture, without the consent of the holders of all the bonds then outstanding, or (3) reduce the aforesaid percentage of the principal amount of bonds the holders of which are required to approve any such supplemental indenture, without the consent of the holders of all the bonds then outstanding. For the purposes of this Section, bonds shall be deemed to be affected by a supplemental indenture if such supplemental indenture adversely affects or

11

diminishes the rights of holders thereof against the Company or against its property.

Upon the written request of the Company, accompanied by a resolution authorizing the execution of any such supplemental indenture, and upon the filing with the Trustee of evidence of the consent of bondholders as aforesaid (the instrument or instruments evidencing such consent to be dated within one year of such request), the Trustee shall join with the Company in the execution of such supplemental indenture unless such supplemental indenture affects the Trustee’s own rights, duties or immunities under this Indenture or otherwise, in which case the Trustee may in its discretion but shall not be obligated to enter into such supplemental indenture. The Trustee shall be entitled to receive and, subject to Section 102 of the Indenture and Article Four of the Supplemental Indenture dated as of April 1, 1940, may rely upon, an opinion of counsel as conclusive evidence that any such supplemental indenture is authorized or permitted by the provisions of this Section.

It shall not be necessary for the consent of the bondholders under this Section to approve the particular form of any proposed supplemental indenture, but it shall be sufficient if such consent shall approve the substance thereof.

The Company and the Trustee, if they so elect, and either before or after such 60% or greater consent has been obtained, may require the holder of any bond consenting to the execution of any such supplemental indenture to submit his bond to the Trustee or to such bank, banker or trust company as may be designated by the Trustee for the purpose, for the notation thereon of the fact that the holder of such bond has consented to the execution of such supplemental indenture, and in such case such notation, in form satisfactory to the Trustee, shall be made upon all bonds so submitted, and such bonds bearing such notation shall forthwith be returned to the persons entitled thereto. All subsequent holders of bonds bearing such notation shall be deemed to have consented to the execution of such supplemental indenture, and consent, once given or deemed to be given, may not be withdrawn.

Prior to the execution by the Company and the Trustee of any supplemental indenture pursuant to the provisions of this Section, the Company shall publish a notice, setting forth in general terms the substance of such supplemental indenture, at least once in one daily newspaper of general circulation in each city in which the principal of any of the bonds shall be payable, or, if all bonds outstanding shall be registered bonds without coupons or coupon bonds registered as to principal, such notice shall be sufficiently given if mailed, first class, postage prepaid, and registered if the Company so elects, to each registered holder of bonds at the last address of such holder appearing on the registry books, such publication or mailing, as the case may be, to be made not less than thirty days prior to such execution. Any failure of the Company to give such notice, or, any defect therein, shall not, however, in any way impair or affect the validity of any such supplemental indenture.”

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Section 4. As supplemented and amended by this Supplemental Indenture, the Indenture is in all respects ratified and confirmed, and this Supplemental Indenture and all the terms and conditions herein contained shall be deemed a part thereof.

Section 5. 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 Indenture as heretofore amended and supplemented. The Trustee shall not be responsible for the recitals herein or in the bonds (other than in the authentication certificate of the Trustee), all of which are made by the Company solely.

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.

Section 7. The Company acknowledges and intends that all advances made to it by the Lenders under the Credit Agreement, including future advances whenever hereafter made, shall be a lien from the time this Supplemental Indenture is recorded, as provided in Section 15-1302(b)(1) of the Illinois Mortgage Foreclosure Law (the “Act”), 735 ILCS 15-1101, et seq. The amount of the bonds of the 2007 Credit Agreement Series which comprises the principal amount then outstanding of the Obligations under the Credit Agreement constitutes revolving credit indebtedness secured by a mortgage on real property, pursuant to the terms and conditions of 205 ILCS 5/5d from the date of this Supplemental Indenture.

Section 8. The Company shall provide the Trustee with copies of the Credit Agreement and any amendments thereto as soon as practicable after such Credit Agreement or amendment is entered into and the Trustee in performing its duties hereunder shall be entitled to rely on the latest copy of the Credit Agreement and any amendments thereto received from the Company. To the extent not identified in the Credit Agreement or amendment, as provided in the preceding sentence, the Company will inform the Trustee of any change in the identity of the Agent and the Trustee shall be entitled to conclusively rely on the notice or instructions received from the Agent pursuant to the Credit Agreement or amendment.

DETAILED DESCRIPTION OF ADDITIONAL PROPERTIES

PARCEL 1

A part of the West Half of the Northwest Quarter of Section 11, Township 22 North, Range 4 West of the Third Principal Meridian, Tazewell County, more particularly described as follows:

Beginning at the Northwest corner of the Northwest Quarter of said Section 11, Thence South 90 degrees 00 minutes 00 seconds East, (Bearing assumed for purpose of description only). Along the North line of the Northwest Quarter of said Section 11, 418.00 feet; Thence South 00 degrees 50 minutes 08 seconds West, 418.00 feet; Thence North 90 degrees 00 minutes 00 seconds West, 418.00 feet to the West line of the Northwest Quarter of said Section 11; Thence North 00 degrees 50 minutes 08 seconds East, along said West line, 418.00 feet to the point of beginning,

13

said tract containing 4.010 acres, more or less, subject to that portion used as public road right of way on the North and West sides, Tazewell County, Illinois.

Subject to the rights of the farm tenant under an existing farm lease.

PIN: 21-21-11-100-001

PARCEL 2

PART OF THE SOUTHEAST QUARTER OF SECTION 8, TOWNSHIP 16 NORTH, RANGE 2 WEST, OF THE THIRD PRINCIPAL MERIDIAN, SANGAMON COUNTY, ILLINOIS, MORE PARTICULARLY DESCRIBED AS FOLLOWS:

COMMENCING AT A FOUND IRON PIN MARKING THE NORTHEAST CORNER OF THE SOUTHEAST QUARTER OF SECTION 8, THENCE NORTH 89 DEGREES 05 MINUTES 56 SECONDS WEST, ALONG THE NORTH LINE OF THE SOUTHEAST QUARTER OF SECTION 8, A DISTANCE OF 1,178.34 FEET; THENCE SOUTH 0 DEGREES 00 MINUTES 00 SECONDS EAST ALONG A LINE PERPENDICULAR TO THE SOUTHERLY RIGHT-OF-WAY LINE OF THE NORFOLK SOUTHERN RAILROAD A DISTANCE OF 33.17 FEET TO THE POINT OF BEGINNING, ALSO BEING A POINT ON THE SOUTHERLY RIGHT-OF-WAY LINE OF THE FORMER ILLINOIS TERMINAL RAILROAD COMPANY (NOW STATE OF ILLINOIS OLD ROUTE 36); THENCE CONTINUING SOUTH 0 DEGREES 00 MINUTES 00 SECONDS EAST A DISTANCE OF 871.50 FEET; THENCE SOUTH 90 DEGREES 00 MINUTES 00 SECONDS WEST A DISTANCE OF 747.91 FEET TO A POINT 72.5 FEET PERPENDICULARLY DISTANT FROM THE CENTERLINE OF AN EXISTING 145 FOOT RIGHT-OF-WAY EASEMENT GRANTED TO COMMONWEALTH EDISON COMPANY FOR AN ELECTRICAL TRANSMISSION LINE; THENCE NORTH 20 DEGREES 06 MINUTES 36 SECONDS EAST ALONG THE EASTERLY LINE OF THE EASEMENT A DISTANCE OF 908.91 FEET TO THE EXISTING SOUTHERLY RIGHT-OF-WAY LINE OF THE FORMER ILLINOIS TERMINAL RAILROAD (NOW STATE OF ILLINOIS OLD ROUTE 36); THENCE SOUTH 90 DEGREES 00 MINUTES 00 SECONDS EAST ALONG THE RIGHT-OF-WAY LINE, ALSO BEING 128.00 FEET AND PARALLEL TO THE EXISTING SOUTHERLY RIGHT-OF-WAY LINE OF THE NORFOLK SOUTHERN RAILROAD, A DISTANCE OF 293.77 FEET; THENCE NORTH 0 DEGREES 00 MINUTES 00 SECONDS EAST, ALONG THE RIGHT-OF-WAY LINE A DISTANCE OF 18.00 FEET; THENCE SOUTH 90 DEGREES 00 MINUTES 00 SECONDS ALONG THE RIGHT-OF-WAY LINE A DISTANCE OF 141.63 FEET TO THE POINT OF BEGINNING, CONTAINING 11.651 ACRES, MORE OR LESS.

EXCEPTING FROM THE ABOVE-DESCRIBED REAL ESTATE, ALL MINERALS UNDERLYING THE SURFACE THEREOF WITH THE RIGHT TO MINE AND REMOVE THE SAME, BUT PROHIBITING SURFACE ENTRY FOR EXTRACTION OF THE MINERALS OR FOR ANY OTHER PURPOSE WHATSOEVER AND PROHIBITING ANY UNDERGROUND MINING METHOD THAT WOULD CAUSE THE SURFACE OF THE PROPERTY TO SUBSIDE.

14

IN WITNESS WHEREOF, Central Illinois Light Company, party of the first part hereto, and Deutsche Bank Trust Company Americas, party of the second part hereto, have caused these presents to be executed in their respective names by their respective Presidents or one of their Vice Presidents or one of their Assistant Vice Presidents and their respective seals to be hereunto affixed and attested by their respective Secretaries or one of their Assistant Secretaries or one of their Associates, all as of the day and year first above written.

	Central Illinois Light Company By /s/ Jerre E. Birdsong                     Name: Jerre E. Birdsong Title: Vice President and Treasurer
[Seal] Attest:       /s/ Craig W. Stensland                   Name: Craig W. Stensland Title: Assistant Secretary

15

	Deutsche Bank Trust Company Americas, as Trustee By Deutsche Bank National Trust Company By /s/ Irina Golovashchuk          Name: Irina Golovashchuk Title: Assistant Vice President
	By /s/ Rodney Gaughan              Name: Rodney Gaughan Title: Assistant Vice President
[Seal] Attest:       /s/ Yana Kalachikova                   Name: Yana Kalachikova Title: Assistant Vice President

16

State of Missouri  )

 ) SS

City of St. Louis    )

I, Carla J. Finn, a Notary Public, do hereby certify that Jerre E. Birdsong, Vice President and Treasurer of Central Illinois Light Company, a corporation organized and existing under the laws of the State of Illinois, and Craig W. Stensland, Assistant Secretary of said corporation, who are both personally known to me to be the same persons whose names are subscribed to the foregoing instrument as such officers, respectively, of said corporation, and who are both personally known to me to be such officers, appeared before me this day in person and severally acknowledged that they signed, sealed and delivered said instrument as their free and voluntary act as such officers, and as the free and voluntary act of said corporation, for the uses and purposes therein set forth.

Given under my hand and official seal this 5^th day of March, 2007, in the City and State aforesaid.

	/s/ Carla J. Flinn
	Notary Public
(Notarial Seal)

Commission # 06399906

My Commission expires 4/20/2010

17

State of New Jersey  )

                                     ) SS

County of Union       )

I, Tracy Mantone, a Notary Public in and for Union County in the State aforesaid, do hereby certify that:

Irina Golovashcuk, an Assistant Vice President of Deutsche Bank National Trust Company, signing on behalf of Deutsche Bank Trust Company Americas, and Rodney Gaughan, an Assistant Vice President of said corporation, who are both personally known to me to be the same persons whose names are subscribed to the foregoing instrument as such officers, respectively, of said corporation, and who are both personally known to me to be such officers, appeared before me this day in person and severally acknowledged that they signed, sealed and delivered said instrument as their free and voluntary act as such officers, and as the free and voluntary act of said corporation, for the uses and purposes therein set forth.

Given under my hand and official seal this 5th day of March, 2007.

	/s/ Tracy Mantone
	Notary Public
(Notarial Seal)

My Commission expires 2012

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EX-4.6

Exhibit 4.6

When Recorded Mail to:

Illinois Power Company

Craig W. Stensland

One Ameren Plaza (MC 1310)

1901 Chouteau Avenue

St. Louis, MO 63103

ILLINOIS POWER COMPANY

TO

BNY MIDWEST TRUST COMPANY,

AS SUCCESSOR TRUSTEE TO

HARRIS TRUST AND SAVINGS BANK

SUPPLEMENTAL INDENTURE

DATED AS OFMARCH 1, 2007

TO

GENERAL MORTGAGE INDENTURE AND DEED OF TRUST

DATED AS OF NOVEMBER 1, 1992

This instrument was prepared by Steven R. Sullivan, Senior Vice President, General Counsel and Secretary of Illinois Power Company c/o Ameren Corporation, One Ameren Plaza, 1901 Chouteau Avenue, St. Louis, Missouri 63103.

SUPPLEMENTAL INDENTURE dated as of March 1, 2007 (“Supplemental Indenture”), made by and between ILLINOIS POWER COMPANY, a corporation organized and existing under the laws of the State of Illinois (the “Company”), party of the first part, and BNY MIDWEST TRUST COMPANY, a corporation organized and existing under the laws of the State of Illinois, as successor trustee to Harris Trust and Savings Bank, a corporation organized and existing under the laws of the State of Illinois (the “Trustee”), as Trustee under the General Mortgage Indenture and Deed of Trust dated as of November 1, 1992, hereinafter mentioned, party of the second part;

WHEREAS, the Company has heretofore executed and delivered its General Mortgage Indenture and Deed of Trust dated as of November 1, 1992 as from time to time amended (the “Indenture”), to the Trustee, for the security of the Bonds of the Company issued and to be issued thereunder (the “Bonds”); and

WHEREAS, pursuant to the terms and provisions of the Indenture there were created and authorized by supplemental indentures thereto bearing the following dates, respectively, the Mortgage Bonds of the series issued thereunder and respectively identified opposite such dates:

DATE OF SUPPLEMENTAL INDENTURE	IDENTIFICATION OF SERIES	CALLED
February 15, 1993	8% Series due 2023 (redeemed)	Bonds of the 2023 Series
March 15, 1993	6 1/8% Series due 2000 (paid at maturity)	Bonds of the 2000 Series
March 15, 1993	6 3/4% Series due 2005 (paid at maturity)	Bonds of the 2005 Series
July 15, 1993	7 1/2% Series due 2025 (redeemed)	Bonds of the 2025 Series
August 1, 1993	6 1/2% Series due 2003 (paid at maturity)	Bonds of the 2003 Series
October 15, 1993	5 5/8% Series due 2000 (paid at maturity)	Bonds of the Second 2000 Series
November 1, 1993	Pollution Control Series M (redeemed)	Bonds of the Pollution Control Series M
November 1, 1993	Pollution Control Series N (redeemed)	Bonds of the Pollution Control Series N
November 1, 1993	Pollution Control Series O (redeemed)	Bonds of the Pollution Control Series O

 

DATE OF SUPPLEMENTAL INDENTURE   IDENTIFICATION OF SERIES   CALLED  

April 1, 1997	Pollution Control Series P	Bonds of the Pollution Control Series P
April 1, 1997	Pollution Control Series Q	Bonds of the Pollution Control Series Q
April 1, 1997	Pollution Control Series R	Bonds of the Pollution Control Series R
March 1, 1998	Pollution Control Series S	Bonds of the Pollution Control Series S
March 1, 1998	Pollution Control Series T	Bonds of the Pollution Control Series T
July 15, 1998	6 1/4% Series due 2002 (paid at maturity)	Bonds of the 2002 Series
September 15, 1998	6% Series due 2003 (paid at maturity)	Bonds of the Second 2003 Series
June 15, 1999	7.50% Series due 2009	Bonds of the 2009 Series
July 15, 1999	Pollution Control Series U	Bonds of the Pollution Control Series U
July 15, 1999	Pollution Control Series V (redeemed)	Bonds of the Pollution Control Series V
May 1, 2001	Pollution Control Series W	Bonds of the Pollution Control Series W
May 1, 2001	Pollution Control Series X	Bonds of the Pollution Control Series X
July 1, 2002	10 5/8% Series due 2007 (not issued)	Bonds of the 2007 Series
July 1, 2002	10 5/8% Series due 2012 (not issued)	Bonds of the 2012 Series
December 15, 2002	11.50% Series due 2010	Bonds of the 2010 Series

2

June 1, 2006	Mortgage Bonds, Senior Notes Series AA	Bonds of Series AA
August 1, 2006	Mortgage Bonds, 2006 Credit Agreement Series Bonds	2006 Credit Agreement Series Bonds

and

WHEREAS, a supplemental indenture with respect to the Bonds of the 2007 Series and the Bonds of the 2012 Series listed above was executed and filed but such Bonds of the 2007 Series and Bonds of the 2012 Series were never issued and a release with respect to such supplemental indenture was subsequently executed and filed; and

WHEREAS, the Company has entered into a Credit Agreement, dated as of February 9, 2007 (as amended or otherwise modified from time to time, the “Credit Agreement”) by and among the Company, Central Illinois Light Company, Central Illinois Public Service Company, AmerenEnergy Resources Generating Company and CILCORP Inc., as borrowers, the lenders from time to time party thereto (the “Lenders”) and JPMorgan Chase Bank, N.A., as agent (in such capacity, the “Agent”) for the Lenders, providing for the making of certain financial accommodations thereunder to the Company, and pursuant to such Credit Agreement, the Company has agreed to issue to the Agent, as evidence of and security for the Obligations (as such term is defined in the Credit Agreement) of the Company (the “Company Obligations”), a new series of Bonds under the Indenture; and

WHEREAS, for such purposes, the Company desires to create a new series of Bonds to be issued under the Indenture to be known as Mortgage Bonds, 2007 Credit Agreement Series (the “2007 Credit Agreement Series Bonds”); and

WHEREAS, the 2007 Credit Agreement Series Bonds shall be issued to the Agent as evidence of and security for the Company Obligations under the Credit Agreement; and

WHEREAS, the Company, in the exercise of the powers and authority conferred upon and reserved to it under the provisions of the Indenture, and pursuant to appropriate resolutions of the Board of Directors, has duly resolved and determined to make, execute and deliver to the Trustee this Supplemental Indenture in the form hereof for the purposes herein provided; and

WHEREAS, all conditions and requirements necessary to make this Supplemental Indenture a valid, binding and legal instrument have been done, performed and fulfilled and the execution and delivery hereof have been in all respects duly authorized;

NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE

WITNESSETH:

THAT Illinois Power Company, in consideration of the purchase and ownership from time to time of the Bonds and the service by the Trustee, and its successors, under the

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Indenture 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, hereby covenants and agrees to and with the Trustee and its successors in the trust under the Indenture, for the benefit of those who shall hold the Bonds as follows:

ARTICLE I

DESCRIPTION OF 2007 CREDIT AGREEMENT SERIES BONDS.

SECTION 1.The Company hereby creates a new series of Bonds to be known as “2007 Credit Agreement Series Bonds.” The 2007 Credit Agreement Series Bonds shall be executed, authenticated and delivered in accordance with the provisions of, and shall in all respects be subject to, all of the terms, conditions and covenants of the Indenture, as supplemented and modified. The 2007 Credit Agreement Series Bonds shall be issued only to and in the name of the Agent under the Credit Agreement to evidence and secure any and all Company Obligations under the Credit Agreement.

The 2007 Credit Agreement Series Bonds shall be dated as of the Interest Payment Date (as defined below) thereof to which interest was paid next preceding the date of issue, unless (a) issued on an Interest Payment Date thereof to which interest was paid, in which event it shall be dated as of such issue date, or (b) issued prior to the occurrence of the first Interest Payment Date thereof to which interest was paid, in which event it shall be dated the date of original issuance.

The 2007 Credit Agreement Series Bonds shall be issued in the aggregate principal amount of $200,000,000 and shall mature on the Maturity Date (having at any time the meaning such term has at such time under the Credit Agreement) applicable to the Company.

The 2007 Credit Agreement Series Bonds shall bear interest from their date as set forth in the form thereof hereinafter recited. Interest on the 2007 Credit Agreement Series Bonds shall be payable on each Interest Payment Date (defined below), commencing on the first Interest Payment Date next succeeding the date of the 2007 Credit Agreement Series Bonds. Payment of principal on the 2007 Credit Agreement Series Bonds shall be due on the Maturity Date. If the Maturity Date falls on a day which is not a Business Day, as defined below, principal and any interest and/or fees payable by the Company with respect to the Maturity Date will be paid on the next succeeding Business Day.

Both the principal of and the interest on the 2007 Credit Agreement Series Bonds shall be payable at the times and in the manner set forth in the form of bond set out herein and in immediately available funds at the office or agency of the Trustee, in any coin or currency of the United States of America which at the time of payment is legal tender for public and private debts.

The obligation of the Company to make payments with respect to principal under the Credit Agreement shall not give rise to an obligation to pay principal of the 2007 Credit Agreement Series Bonds except on the Maturity Date of the Company or upon redemption as provided in this Supplemental Indenture. If at any time any permanent reduction of the

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Borrower Sublimit (as defined in the Credit Agreement) of the Company or the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company shall result in the principal of the 2007 Credit Agreement Series Bonds being greater than the greater of the Borrower Sublimit and the Borrower Credit Exposure, a payment obligation with respect to the principal of the 2007 Credit Agreement Series Bonds in the amount of such excess shall be deemed discharged upon the effectiveness of such permanent reduction. No payment of principal under the Credit Agreement shall reduce the principal amount of the2007 Credit Agreement Series Bonds to an amount less than the greater of the Borrower Sublimit and the Borrower Credit Exposure.

The obligation of the Company to make payments with respect to the interest on the 2007 Credit Agreement Series Bonds shall be fully or partially, as the case may be, satisfied and discharged to the extent that, at the time that any such payment shall be due, the then due interest and/or fees of the Company under the Credit Agreement shall have been fully or partially paid. Satisfaction of any obligation to the extent that payment is made with respect to the interest and/or fees of the Company under the Credit Agreement means that if any payment is made on the interest and/or fees of the Company under the Credit Agreement, a corresponding payment obligation with respect to the interest on the 2007 Credit Agreement Series Bonds shall be deemed discharged in the same amount as such payment made on the interest and/or fees of the Company under the Credit Agreement.

The Trustee may at any time and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of and interest on the 2007 Credit Agreement Series Bonds, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to the foregoing paragraphs unless and until the Trustee shall have received a written notice from the Agent stating (i) that timely payment of principal of or interest on the 2007 Credit Agreement Series Bonds has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the Agent in connection with the Company Obligations pursuant to the Credit Agreement, and (iii) the amount of the arrearage.

As used herein, (A) “Business Day” shall have the meaning assigned thereto in the Credit Agreement; (B) “Interest Payment Date” shall mean each date on which Company Obligations constituting interest and/or fees are due and payable from time to time pursuant to the Credit Agreement; (C) “Interest Rate” shall mean a rate of interest per annum, adjusted as necessary, to result in an interest payment equal to the aggregate amount of Company Obligations constituting interest and fees of the Company due under the Credit Agreement on the applicable Interest Payment Date; and (D) “Record Date” with respect to any Interest Payment Date shall mean the day (whether or not a Business Day) immediately next preceding such Interest Payment Date.

The 2007 Credit Agreement Series Bonds shall not be assignable or transferable except to a successor Agent appointed in accordance with the Credit Agreement. The 2007 Credit Agreement Series Bondsare exchangeable by the Registered Owner thereof, in person or by attorney duly authorized, at the principal office or place of business of the Trustee under the Indenture, upon the surrender and cancellation of said bonds and the payment of any stamp tax or other governmental charge, and upon any such exchange a new registered bond or bonds without coupons, of the same series and maturity and for the same aggregate principal amount, will be issued in exchange theretofore; provided, that the Company shall not be required to

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exchange any 2007 Credit Agreement Series Bonds for a period of ten (10) days next preceding an Interest Payment Date with respect to such bonds.

As provided in Section 8.4 of the Credit Agreement, the Agent shall surrender the 2007 Credit Agreement Series Bonds to the Trustee for cancellation when each of the Borrower Sublimit and the Borrower Credit Exposure of the Company have been reduced to zero and all fees and other amounts payable by the Company pursuant to the Credit Agreement with respect to the Company Obligations shall have been duly paid.

SECTION 2.The 2007 Credit Agreement Series Bonds and the Trustee’s Certificate of Authentication shall be substantially in the following forms respectively:

[FORM OF FACE OF BOND]

ILLINOIS POWER COMPANY

(Incorporated under the laws of the State of Illinois)

Notwithstanding any provisions hereof or in the Indenture

this Bond is not assignable or transferable except to a successor Agent appointed in

accordance with the Credit Agreement, dated

as of February 9, 2007, hereinafter referred to.

Illinois Commerce Commission

Identification No.: ____

MORTGAGE BONDS, 2007 CREDIT AGREEMENT SERIES

No. ________                                                                                                                                                                        & #160;                                                                                       $200,000,000

ILLINOIS POWER COMPANY, a corporation organized and existing under the laws of the State of Illinois (the “Company”), which term shall include any successor corporation as defined in the Indenture hereinafter referred to, for value received, hereby promises to pay to JPMorgan Chase Bank, N.A., as agent (in such capacity, the “Agent”) for the Lenders (as defined below) under the Credit Agreement, dated as of February 9, 2007, by and among the Company, Central Illinois Light Company, Central Illinois Public Service Company, AmerenEnergy Resources Generating Company and CILCORP Inc., as borrowers, the lenders from time to time party thereto (the “Lenders”) and JPMorgan Chase Bank, N.A., as agent (as amended or otherwise modified from time to time, the “Credit Agreement”), or registered assigns, the principal sum of $200,000,000or such lesser principal amount as shall be equal to the amount of the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company outstanding on the Maturity Date (having at any time the meaning such term has at such time under the Credit Agreement) of the Company, but not in excess of the principal amount of this Bond, and to pay interest thereon at the Interest Rate (as defined below) until the principal hereof is paid or duly made available for payment on the Maturity Date or in the event of redemption of this Bond, until the redemption date.

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Interest on this Bond shall be payable on each Interest Payment Date (as defined below), commencing on the first Interest Payment Date next succeeding the date of this Bond. If the Maturity Date falls on a day which is not a Business Day, as defined below, principal and any interest and/or fees payable with respect to the Maturity Date will be paid on the next succeeding Business Day. The interest payable, and punctually paid or duly provided for, on any Interest Payment Date will, subject to certain exceptions provided in the Supplemental Indenture dated as of March 1, 2007, hereinafter referred to, be paid to the person in whose name this Bond (or one or more predecessor bonds) is registered at the close of business on the Record Date (as defined below); provided, however, that interest payable on the Maturity Date will be payable to the person to whom the principal hereof shall be payable. Should the Company default in the payment of interest (“Defaulted Interest”), the Defaulted Interest shall be paid to the person in whose name this Bond is registered on the Record Date to be established by the Trustee for payment of such Defaulted Interest. As used herein, (A) “Business Day” shall have the meaning assigned thereto in the Credit Agreement; (B) “Interest Payment Date” shall mean each date on which Company Obligations constituting interest and/or fees are due and payable from time to time pursuant to the Credit Agreement; (C) “Interest Rate” shall mean a rate of interest per annum, adjusted as necessary, to result in an interest payment equal to the aggregate amount of Company Obligations constituting interest and fees of the Company due under the Credit Agreement on the applicable Interest Payment Date; and (D) “Record Date” with respect to any Interest Payment Date shall mean the day (whether or not a Business Day) immediately next preceding such Interest Payment Date.

Both the principal of and the interest on this Bond shall be payable in immediately available funds at the office or agency of the Trustee, in any coin or currency of the United States of America which at the time of payment is legal tender for public and private debts.

This Bond is to be issued and delivered to the Agent in order to evidence and secure the obligations of the Company under the Credit Agreement to make payments to the Lenders under the Credit Agreement and to provide the Lenders the benefit of the lien of the Indenture with respect to the 2007 Credit Agreement Series Bonds.

The obligation of the Company to make payments with respect to principal under the Credit Agreement shall not give rise to an obligation to pay principal of the 2007 Credit Agreement Series Bonds except on the Maturity Date of the Company or upon redemption hereof. If at any time any permanent reduction of the Borrower Sublimit (as defined in the Credit Agreement) of the Company or the Borrower Credit Exposure (as defined in the Credit Agreement) of the Company shall result in the principal of the 2007 Credit Agreement Series Bonds being greater than the greater of the Borrower Sublimit and the Borrower Credit Exposure, a payment obligation with respect to the principal of the 2007 Credit Agreement Series Bonds in the amount of such excess shall be deemed discharged upon the effectiveness of such permanent reduction. No payment of principal under the Credit Agreement shall reduce the principal amount of the2007 Credit Agreement Series Bonds to an amount less than the greater of the Borrower Sublimit and the Borrower Credit Exposure.

The obligation of the Company to make payments with respect to the interest on this Bond shall be fully or partially, as the case may be, satisfied and discharged to the extent that, at the time that any such payment shall be due, the then due interest and/or fees of the

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Company under the Credit Agreement shall have been fully or partially paid. Satisfaction of any obligation to the extent that payment is made with respect to the interest and/or fees of the Company under the Credit Agreement means that if any payment is made on the interest and/or fees of the Company under the Credit Agreement, a corresponding payment obligation with respect to the interest on this Bond shall be deemed discharged in the same amount as such payment made on the interest and/or fees of the Company under the Credit Agreement.

The Trustee may at any time and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of and interest on this Bond, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to the foregoing paragraphs unless and until the Trustee shall have received a written notice from the Agent stating (i) that timely payment of principal of or interest on this Bond has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the Agent in connection with the Company Obligations pursuant to the Credit Agreement, and (iii) the amount of the arrearage.

The Agent shall surrender this Bond to the Trustee when each of the Borrower Sublimit and the Borrower Credit Exposure of the Company have been reduced to zero and all fees and other amounts payable by the Company pursuant to the Credit Agreement with respect to the Company Obligations shall have been duly paid.

This Bond shall not be entitled to any benefit under the Indenture or any indenture supplemental thereto, or become valid or obligatory for any purpose, until the form of certificate endorsed hereon shall have been signed by or on behalf of BNY Midwest Trust Company, as successor trustee to Harris Trust and Savings Bank, the Trustee under the Indenture, or a successor trustee thereto under the Indenture (the “Trustee”).

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.

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IN WITNESS WHEREOF, Illinois Power Company has caused this Bond to be signed (manually or by facsimile signature) in its name by an Authorized Executive Officer, as defined in the aforesaid Indenture, and attested (manually or by facsimile signature) by an Authorized Executive Officer, as defined in such Indenture on the date hereof.

Dated March 9, 2007

ILLINOIS POWER COMPANY

By:   _________________________________

AUTHORIZED EXECUTIVE OFFICER

ATTEST:

By:

______________________________

AUTHORIZED EXECUTIVE OFFICER

[FORM OF TRUSTEE’S CERTIFICATE OF AUTHENTICATION]

This is one of the Bonds of the series designated therein referred to in the within-mentioned Indenture and the Supplemental Indenture dated as of March 1, 2007.

BNY MIDWEST TRUST COMPANY, successor

               trustee to Harris Trust and Savings, Bank,

                                                                          TRUSTEE,

By:   _______________________________________            

AUTHORIZED SIGNATORY

[FORM OF REVERSE OF BOND]

This Bond is one of a duly authorized issue of Bonds of the Company (the “Bonds”) in unlimited aggregate principal amount, of the series hereinafter specified, all issued and to be issued under and equally secured by the General Mortgage Indenture and Deed of Trust (the “Indenture”), dated as of November 1, 1992, executed by the Company to BNY Midwest Trust Company, as successor trustee to Harris Trust and Savings Bank (the “Trustee”) to which Indenture and all indentures supplemental thereto reference is hereby made for a description of the properties mortgaged and pledged, the nature and extent of the security, the rights of registered owners of the Bonds and of the Trustee in respect thereof, and the terms and conditions upon which the Bonds are, and are to be, secured. The Bonds may be issued in series, for various principal sums, may mature at different times, may bear interest at different rates and may otherwise vary as provided in the Indenture. This Bond is one of a series designated as the “Mortgage Bonds, 2007 Credit Agreement Series” (the “2007 Credit Agreement Series Bonds”)

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of the Company, in an aggregate principal amount of $200,000,000 issued under and secured by the Indenture and described in the Supplemental Indenture dated as of March 1, 2007 (the “Supplemental Indenture of March 1, 2007”), between the Company and the Trustee, supplemental to the Indenture.

This 2007 Credit Agreement Series Bond is not redeemable except upon written demand of the Agent following the occurrence of a Default by the Company under the Credit Agreement and the acceleration of the Company Obligations, as provided under the Credit Agreement.

In case an Event of Default, as defined in the Indenture, shall occur, the principal of all Bonds at any such time outstanding under the Indenture may be declared or may become due and payable, upon the conditions and in the manner and with the effect provided in the Indenture. The Indenture provides that such declaration may be rescinded under certain circumstances.

ARTICLE II

REDEMPTION.

SECTION 1.Except as set forth herein, the 2007 Credit Agreement Series Bonds are not redeemable. Upon the occurrence of a Default by the Company under the Credit Agreement and the acceleration of the Company Obligations, the 2007 Credit Agreement Series Bonds shall be redeemable in whole upon receipt by the Trustee of a written demand from the Agent stating that there has occurred under the Credit Agreement both a Default by the Company and a declaration of acceleration of the Company Obligations and demanding redemption of the 2007 Credit Agreement Series Bonds (including a description of the amount of principal, interest, fees cash collateralization obligations and other amounts which comprise such Company Obligations). The Company waives any right it may have to prior notice of such redemption under the Indenture and any other notice required under the Indenture, including notice to be given by the Company, shall be deemed satisfied by the notice given by the Agent as aforesaid. Upon surrender of the 2007 Credit Agreement Series Bonds by the Agent to the Trustee, the 2007 Credit Agreement Series Bonds shall be redeemed at a redemption price equal to the aggregate amount of the Company Obligations.

ARTICLE III

ISSUE OF 2007 CREDIT AGREEMENT SERIES BONDS.

SECTION 1.The Company hereby exercises the right to obtain the authentication of $200,000,000 principal amount of additional Bonds pursuant to the terms of Section 4.04 of the Indenture, all of which shall be 2007 Credit Agreement Series Bonds.

SECTION 2.Such 2007 Credit Agreement Series Bonds may be authenticated and delivered prior to the filing for recordation of this Supplemental Indenture.

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ARTICLE IV

THE TRUSTEE.

The Trustee hereby accepts the trusts hereby declared and provided, and agrees to perform the same upon the terms and conditions in the Indenture set forth and upon the following terms and conditions:

The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or the due execution hereof by the Company or for or in respect of the recitals contained herein, all of which recitals are made by the Company solely. In general, each and every term and condition contained in Article Eleven of the Indenture shall apply to this Supplemental Indenture with the same force and effect as if the same were herein set forth in full, with such omissions, variations and modifications thereof as may be appropriate to make the same conform to this Supplemental Indenture.

ARTICLE V

MISCELLANEOUS PROVISIONS.

This Supplemental Indenture may be simultaneously executed in any number of counterparts, each of which when so executed shall be deemed to be an original; but such counterparts shall together constitute but one and the same instrument.

The Company acknowledges and intends that all advances made to it by the Lenders under the Credit Agreement, including future advances whenever hereafter made, shall be a lien from the time this Supplemental Indenture is recorded, as provided in Section 15-1302(b)(1) of the Illinois Mortgage Foreclosure Law (the “Act”), 735 ILCS 15-1101, et seq. The amount of the bonds of the 2007 Credit Agreement Series which comprises the principal amount then outstanding of the Obligations under the Credit Agreement constitutes revolving credit indebtedness secured by a mortgage on real property, pursuant to the terms and conditions of 205 ILCS 5/5d from the date of this Supplemental Indenture.

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IN WITNESS WHEREOF, said Illinois Power Company has caused this Supplemental Indenture to be executed on its behalf by an Authorized Executive Officer as defined in the Indenture, and this Supplemental Indenture to be attested by an Authorized Executive Officer as defined in the Indenture; and said BNY Midwest Trust Company, as successor trustee to Harris Trust and Savings Bank, in evidence of its acceptance of the trust hereby created, has caused this Supplemental Indenture to be executed on its behalf by its President or one of its Vice Presidents and this Supplemental Indenture to be attested by its Secretary or one of its Vice Presidents; all as of the 1^st day of March, 2007.

	ILLINOIS POWER COMPANY
	By  /s/ Jerre E. Birdsong                        Name: Jerre E. Birdsong Title: Vice President and Treasurer
ATTEST:
By: /s/ G. L. Waters
Name: G. L. Waters Title: Assistant Secretary

BNY MIDWEST TRUST COMPANY, successor

trustee to Harris Trust and Savings, Bank,

TRUSTEE,

By:                /s/ J. Bartolini                                     

AUTHORIZED SIGNATORY

ATTEST:

By:  /s/ M. Callahan     

Name: M. Callahan

Title: Vice President

STATE OF MISSOURI   )

)SS.

CITY OF ST. LOUIS        )

BE IT REMEMBERED, that on this 5^th day of March, 2007, before me, the undersigned, a Notary Public within and for the City and State aforesaid, personally came Jerre E. Birdsong, Vice President and Treasurer and G. L. Waters, Assistant Secretary, of Illinois Power Company, a corporation duly organized, incorporated and existing under the laws of the State of Illinois, who are personally known to me to be such officers, and who are personally known to me to be the same persons who executed as such officers the within instrument of writing, and such persons duly acknowledged that they signed and delivered the said instrument as their free and voluntary act as such officers and as the free and voluntary act of said Illinois Power Company for the uses and purposes therein set forth.

IN WITNESS WHEREOF, I have hereunto subscribed my name and affixed my official seal on the day and year last above written.

By:  /s/ Carla J. Flinn                      

       NOTARY PUBLIC

My Commission Expires on 4/20/2010.

(NOTARIAL SEAL)

STATE OF ILLINOIS  )

)SS.

COUNTY OF COOK    )

BE IT REMEMBERED, that on this 5th day of March, 2007, before me, the undersigned, a Notary Public within and for the County and State aforesaid, personally came J. Bartolini, Authorized Signatory and M. Callahan, Vice President, of BNY Midwest Trust Company, a corporation duly organized, incorporated and existing under the laws of the State of Illinois, who are personally known to me to be the same persons who executed as such officers the within instrument of writing, and such persons duly acknowledged that they signed, sealed and delivered the said instrument as their free and voluntary act as such officers, and as the free and voluntary act of said BNY Midwest Trust Company for the uses and purposes therein set forth.

IN WITNESS WHEREOF, I have hereunto subscribed my name and affixed my official seal on the day and year last above written.

By:  /s/ Julie Braun                                         

NOTARY PUBLIC, COOK COUNTY,

ILLINOIS

My Commission Expires on 6/23/10

(NOTARIAL SEAL)