Exhibit 10.3

# SECOND AMENDEDAMEREN CORPORATION SYSTEM
UTILITY MONEY POOL AGREEMENT

This
UTILITY MONEY POOL AGREEMENT made and entered into on the 25th day of March, 1999, as
amended September 15, 2003 and October 20, 2003 by and among Ameren Corporation
(Ameren), a Missouri corporation and a registered holding company under the
Public Utility Holding Company Act of 1935, as amended (the Act); Ameren
Services Company (Ameren Services), a Missouri corporation and a subsidiary
service company of Ameren; Union Electric Company, doing business as AmerenUE
(AmerenUE), a Missouri corporation and a utility subsidiary of Ameren; Central
Illinois Public Service Company, doing business as AmerenCIPS (AmerenCIPS), an
Illinois corporation and a utility subsidiary of Ameren, Central Illinois Light Company,
doing business as AmerenCILCO (AmerenCILCO), an Illinois corporation and an
indirect utility subsidiary of Ameren and AmerenEnergy Resources Generating Company, an
Illinois corporation and direct subsidiary of AmerenCILCO (AERG) (each a
Party and collectively, the Parties).

WHEREFORE,
the Parties from time to time have need to borrow funds on a short-term basis, and some of
the Parties from time to time are expected to have funds available to loan on a short-term
basis;

WHEREAS,
by the Utility Money Pool Agreement (Agreement) dated March 25, 1999 all of
the Parties, except AmerenCILCOand AERG, established a pool (the Utility
Money Pool) to coordinate and provide for certain of their short-term cash and
working capital requirements;

WHEREAS,
on January 31, 2003 Ameren acquired CILCORP Inc. including AmerenCILCO;

WHEREAS, the
Agreement dated March 25, 1999 was amended on September 15, 2003 to add AmerenCILCO
as a party to the Utility Money Pool and to make minor changes to the Utility Money Pool
Agreement;

WHEREAS,
effective October 3, 2003 AmerenCILCO transferred certain electric generating assets to
AERG and AERG commenced operations as a public utility as defined by the Act;

WHEREAS,
AERG is not a utility under Illinois law; and

WHEREAS, the
Parties desire to add AERG as a party to the Agreement and to allow AERG to be a lender
to, but not a borrower from, the Utility Money Pool.

NOW
THEREFORE, in consideration of the premises, and the mutual promises set forth herein, the
Parties hereto agree as follows:

ARTICLE
I        CONTRIBUTIONS AND BORROWINGS

Section
1.1 Contributions to Utility Money Pool. Each Party will determine each day, on the basis
of cash flow projections and other relevant factors, in such Partys sole discretion,
the amount of funds it has available for contribution to the Utility Money Pool, and will
contribute such funds to the Utility Money Pool. The determination of whether a Party at
any time has surplus funds to lend to the Utility Money Pool or shall lend funds to the
Utility Money Pool will be made by such Partys Treasurer, or by a designee thereof,
on the basis of cash flow projections and other relevant factors, in such Partys
sole discretion. Each Party may withdraw any of its funds at any time upon notice to
Ameren Services as administrative agent of the Utility Money Pool.

Section
1.2 Rights to Borrow. Subject to the provisions of Section 1.4(b) of this Agreement,
short-term borrowing needs of the Parties, with the exception of Ameren and
AERG, may be met by funds in the Utility Money Pool to the extent such funds are
available. Each Party (other than Ameren and AERG) shall have the right to make
short-term borrowings from the Utility Money Pool from time to time, subject to the
availability of funds and the limitations and conditions set forth herein and in the
applicable orders of the Securities and Exchange Commission (SEC).
AmerenUEs aggregate principal amount of borrowings outstanding at any one time from
the Utility Money Pool will be limited to $500 million. Each Party (other than Ameren
and AERG) may request loans from the Utility Money Pool from time to time during the
period from the date hereof until this Agreement is terminated by written agreement of the
Parties; provided, however, that the aggregate amount of all loans requested by any Party
hereunder shall not exceed the applicable borrowing limits set forth in applicable orders
of the SEC and other relevant regulatory authorities, resolutions of such Partys
shareholders and Board of Directors, such Partys governing corporate documents, and
agreements binding upon such Party. No Party shall be obligated to borrow from the Utility
Money Pool if lower cost funds can be obtained from external borrowing. No loans through
the Utility Money Pool will be made to, and no borrowings through the Utility Money Pool
will be made by, Ameren or AERG.

Section
1.3 Source of Funds. (a) Funds will be available through the Utility Money Pool from the
following sources for use by the Parties from time to time: (i) surplus funds in the
treasuries of Parties other than Ameren, (ii) surplus funds in the treasury of Ameren, and
(iii) proceeds from bank borrowings and the sale of commercial paper by Parties
(External Funds), in each case to the extent permitted by applicable laws and
regulatory orders. Funds will be made available from such sources in such other order as
Ameren Services, as administrator of the Utility Money Pool, may determine will result in
a lower cost of borrowing to Parties borrowing from the Utility Money Pool,

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consistent with the individual borrowing needs
and financial standing of the Parties providing funds to the Utility Money Pool.

(b)       
          Borrowing Parties will borrow pro rata from each lending Party in the proportion
          that the total amount loaned by such lending Party bears to the total amount
          then loaned through the Utility Money Pool. On any day when more than one fund
          source (e.g., surplus treasury funds of Ameren and other Utility Money Pool
          participants (Internal Funds) and External Funds), with different
          rates of interest, is used to fund loans through the Utility Money Pool, each
          borrowing Party will borrow pro rata from each fund source in the same
          proportion that the amount of funds provided by that fund source bears to the
          total amount of short-term funds available in the Utility Money Pool.

(b)       
          All borrowings from the Utility Money Pool shall be authorized by the borrowing
          Partys Treasurer, or by a designee thereof. No Party shall be required to
          effect a borrowing through the Utility Money Pool if such Party determines that
          it can (and is authorized to) effect such borrowing at lower cost directly from
          banks or through the sale of its own commercial paper in an existing commercial
          paper program.

Section
1.5 Interest. Each Party receiving a loan shall accrue interest monthly on the unpaid
principal amount of such loan in the Utility Money Pool from the date of such loan until
such principal amount shall be paid in full.

(a)       
          If only Internal Funds comprise the funds available in the Utility Money Pool,
          the interest rate applicable to loans of such Internal Funds shall be the CD
          yield equivalent of the 30-day Federal Reserve AA Non-Financial
          commercial paper composite rate (or, if no such rate is established for that
          day, then the applicable rate shall be the rate for the next preceding day for
          which such rate was established).

(b)       
          If only External Funds comprise the funds available in the Utility Money Pool,
          the interest rate applicable to loans of such External Funds shall be equal to
          the lending Partys cost for such External Funds (or, if more than one
          Party had made available External Funds on such day, the applicable interest
          rate shall be a composite rate, equal to the weighted average of the cost
          incurred by the respective Parties for such External Funds).

(c)       
          In cases where both Internal Funds and External Funds are concurrently borrowed
          through the Utility Money Pool, the rate applicable to all loans comprised of
          such blended funds shall be a composite rate, equal to the weighted
          average of the (i) cost of all Internal Funds contributed by Parties (as
          determined pursuant to Section 1.5(a) above) and (ii) the cost of all such
          External Funds (as determined pursuant to Section 1.5(b) above); provided, that
          in circumstances where Internal Funds and External Funds are available for loans
          through the Utility Money Pool, loans may be made exclusively

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from Internal Funds or External Funds,
rather than from a blend of such funds, to the extent it is expected that such
loans would result in a lower cost of borrowing.



Section
1.6 Certain Costs. The cost of compensating balances and/or fees paid to banks to maintain
credit lines by Parties lending External Funds to the Utility Money Pool shall initially
be paid by the Party maintaining such line. A portion of such costs shall be retroactively
allocated every month to the Parties borrowing such External Funds through the Utility
Money Pool in proportion to their respective daily outstanding borrowings of such External
Funds.

Section
1.7 Repayment. Each Party receiving a loan hereunder shall repay the principal amount of
such loan, together with all interest accrued thereon, on demand and in any event within
one year of the date on which such loan was made. All loans made through the Utility Money
Pool may be prepaid by the borrower without premium or penalty.

Section
1.8 Form of Loans to Parties. Loans to the Parties through the Utility Money Pool will be
made pursuant to open-account advances, repayable upon demand and in any event not later
than one year after the date of the advance; provided, that each lending Party shall at
all times be entitled to receive upon demand one or more promissory notes evidencing any
and all loans by such lender. Any such note shall: (a) be substantially in the form filed
as Exhibit B to the Form U-1 Application-Declaration in File No. 70-9423, (b) be dated as
of the date of the initial borrowing, (c) mature on demand or on a date agreed by the
Parties to the transaction, but in any event not later than one year after the date of the
applicable borrowing, and (d) be repayable in whole at any time or in part from time to
time, without premium or penalty.

ARTICLE II
        OPERATION
OF UTILITY MONEY POOL

Section
2.1 Operation. Operation of the Utility Money Pool, including record keeping and
coordination of loans, will be handled by Ameren Services under the authority of the
appropriate officers of the Parties. Ameren Services shall be responsible for the
determination of all applicable interest rates and charges to be applied to advances
outstanding at any time hereunder, shall maintain records of all advances, interest
charges and accruals and interest and principal payments for purposes hereof, and shall
prepare periodic reports thereof for the Parties. Ameren Services will administer the
Utility Money Pool on an at cost basis. Separate records shall be kept by
Ameren Services for the Utility Money Pool established by this agreement and any other
money pool administered by Ameren Services.

Section
2.2 Investment of Surplus Funds in the Utility Money Pool. Funds not required to meet
Utility Money Pool loans (with the exception of funds required to satisfy the Utility
Money Pools liquidity requirements) will ordinarily be invested in one or more
short-term investments, including: (i) interest-bearing accounts with banks; (ii)

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obligations issued or guaranteed by the U.S. government and/or its agencies and
instrumentalities, including obligations under repurchase agreements; (iii) obligations
issued or guaranteed by any state or political subdivision thereof, provided that such
obligations are rated not less than A by a nationally recognized rating agency; (iv)
commercial paper rated not less than A-1 or P-1 or their equivalent by a nationally
recognized rating agency; (v) money market funds; (vi) bank certificates of deposit and
bankers acceptances; (vii) Eurodollar certificates of deposit or time deposits; (viii)
investment grade medium term notes, variable rate demand notes and variable rate preferred
stock; and (ix) such other investments as are permitted by Section 9(c) of the Act and
Rule 40 thereunder but only if also permitted by either applicable rule or order by each
state commission having jurisdiction over such investments or by applicable statutes of
each such state.

Section
2.3 Allocation of Interest Income and Investment Earnings. The interest income and other
investment income earned by the Utility Money Pool on loans and investment of surplus
funds will be allocated among the Parties in accordance with the proportion each
Partys contribution of funds in the Utility Money Pool bears to the total amount of
funds in the Utility Money Pool and the cost of any External Funds provided to the Utility
Money Pool by such Party. Interest and other investment earnings will be computed on a
daily basis and settled once per month.

Section
2.4 Event of Default. If any Party shall generally not pay its debts as such debts become
due, or shall admit in writing its inability to pay its debts generally, or shall make a
general assignment for the benefit of creditors, or any proceeding shall be instituted by
or against any Party seeking to adjudicate it a bankrupt or insolvent, then the other
Parties may declare the unpaid principal amount of any loans to such Party, and all
interest thereon, to be forthwith due and payable and all such amounts shall forthwith
become due and payable.

ARTICLE III
        MISCELLANEOUS

Section 3.1  Amendments.  No amendment to this Agreement shall be adopted except in a writing
executed by the Parties.

Section
3.2 Legal Responsibility. Nothing herein contained shall render any Party liable for the
obligations of any other Party hereunder and the rights, obligations and liabilities of
the Parties are several in accordance with their respective obligations, and not joint.

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Section
3.3 Governing Law. This Agreement shall be governed by, and construed in accordance with,
the laws of the State of Missouri.

IN
WITNESS WHEREOF, the undersigned companies have duly caused this document to be signed on
their behalf on the date of amendment written above by the undersigned thereunto duly
authorized.

| |  | AMEREN CORPORATIONBy: /s/ Jerre E. Birdsong
Name:  Jerre E. Birdsong
Title:  Vice President and Treasurer
| |  | -----------------------------------------------------------------------------------------------------------------------

| |  | AMEREN SERVICES COMPANYBy        /s/ Jerre E. Birdsong
Name:  Jerre E. BirdsongTitle:  Vice President and Treasurer
| |  | ---------------------------------------------------------------------------------------------------------------------------------

| |  | UNION ELECTRIC COMPANYBy        /s/ Jerre E. Birdsong
Name:  Jerre E. BirdsongTitle:  Vice President and Treasurer
| |  | --------------------------------------------------------------------------------------------------------------------------------

| |  | CENTRAL ILLINOIS PUBLIC SERVICE COMPANYBy        /s/ Jerre E. Birdsong
Name:  Jerre E. BirdsongTitle:  Vice President and Treasurer
| |  | -------------------------------------------------------------------------------------------------------------------------------------------------

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| |  | CENTRAL ILLINOIS LIGHT COMPANYBy        /s/ Jerre E. Birdsong
Name:  Jerre E. BirdsongTitle:  Vice President and Treasurer
| |  | ----------------------------------------------------------------------------------------------------------------------------------------

| |  | AMERENENERGY RESOURCES GENERATING COMPANYBy        /s/ Jerre E. Birdsong
Name:  Jerre E. BirdsongTitle:  Vice President and Treasurer
| |  | ---------------------------------------------------------------------------------------------------------------------------------------------------

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