SEC FORM 5

SEC Form 5

FORM 5

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

ANNUAL STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Form 3 Holdings Reported.

Form 4 Transactions Reported.

1. Name and Address of Reporting Person^*

WILLIS SAMUEL E

(Last)

(First)

(Middle)

P. O. BOX 66149

(Street)

ST. LOUIS

63166-6149

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
AMEREN CORP [ AEE ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director		10% Owner
Officer (give title below)	X	Other (specify below)
		Vice President of Subsidiary

3. Statement for Issuer's Fiscal Year Ended (Month/Day/Year)
12/31/2003

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)	4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned at end of Issuer's Fiscal Year (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock, $.01 Par Value	01/31/2003⁽¹⁾		I	190⁽¹⁾	A	$38.625⁽¹⁾	1,659	I	By 401K
Common Stock, $.01 Par Value	03/31/2003⁽²⁾		I	125⁽²⁾	A	$39.045⁽²⁾	2,246	I	By ESOP
Common Stock, $.01 Par Value	03/31/2003⁽²⁾		L	151⁽²⁾	A	$39.045⁽²⁾	2,246⁽³⁾	I	By Spouse
Common Stock, $.01 Par Value	03/31/2003⁽⁴⁾		L	341⁽⁴⁾	A	$39.045⁽⁴⁾	7,212	D
Common Stock, $.01 Par Value	06/30/2003⁽⁵⁾		L	55⁽⁵⁾	A	$42.585⁽⁵⁾	7,267	D
Common Stock	02/13/2004		A	1,683⁽⁶⁾	A	$46.34	8,950	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)	5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Stock Option	$35.875						04/25/1997⁽⁷⁾	04/25/2005	Common Stock, $.01 Par Value	700		700	D
Stock Option	$43						02/07/1998⁽⁷⁾	02/07/2006	Common Stock, $.01 Par Value	2,500		3,200	D
Stock Option	$38.5						02/10/1999⁽⁷⁾	02/10/2007	Common Stock, $.01 Par Value	3,400		6,600	D
Stock Option	$39.25						04/28/2000⁽⁷⁾	04/28/2008	Common Stock, $.01 Par Value	9,700		16,300	D
Stock Option	$36.625						02/12/2001⁽⁷⁾	02/12/2009	Common Stock, $.01 Par Value	10,700		27,000	D
Stock Option	$31						02/11/2002⁽⁷⁾	02/11/2010	Common Stock, $.01 Par Value	7,050		34,050	D

Explanation of Responses:

1. Stock was acquired monthly from January through December 2003 at prices ranging from $38.625 to $45.975.

2. Represents shares of stock acquired quarterly during 2003 through reinvested dividends at prices ranging from $39.045 to $45.975.

3. Held in name of spouse, and the undersigned disclaims any beneficial interest in such shares.

4. Represents 2003 dividends on restricted stock. 117 shares for 2001 grant; 112 shares for 2002 grant; and 112 shares for 2003 grant, at prices ranging from $39.045 to $45.975.

5. Represents 18, 19 and 18 shares of stock acquired during the second, third and fourth quarters of 2003 through reinvested dividends of $44.135 at 6/30; $42.585 at 9/30; and 45.975 at 12/31, respectively.

6. Grant of restricted stock.

7. Shares vest in four equal annual installments starting on the exercisable date.

Remarks:

	G. L. Waters, Asst. Secy. for Samuel E. Willis	02/17/2004
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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