QuickLinks
 -- Click here to rapidly navigate through this document

 
 

Exhibit 4.3    
    



	REGISTERED	 	REGISTERED






ILL. C. C. NO. 6285 


THIS
NOTE IS A GLOBAL NOTE REGISTERED IN THE NAME OF THE DEPOSITARY (REFERRED TO HEREIN) OR A NOMINEE THEREOF AND, UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE FOR THE INDIVIDUAL NOTES REPRESENTED HEREBY
AS PROVIDED IN THE INDENTURE REFERRED TO BELOW, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY
OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW YORK), TO THE TRUSTEE FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. 


UNION ELECTRIC COMPANY

4.65% SENIOR SECURED NOTE DUE 2013 



	CUSIP: 906548CB6	 	NUMBER: 1
	ISIN: US906548CB69	 	 
	ORIGINAL ISSUE DATE: October 7, 2003	 	PRINCIPAL AMOUNT: $200,000,000
	INTEREST RATE: 4.65%	 	MATURITY DATE: October 1, 2013





        UNION ELECTRIC COMPANY, a corporation of the State of Missouri (the "COMPANY"), for value received hereby promises to pay to CEDE & CO. or registered
assigns, the principal sum of TWO HUNDRED MILLION DOLLARS ($200,000,000) on the Maturity Date set forth above, and to pay interest thereon from October 7, 2003 or from the most recent Interest
Payment Date to which interest has been paid or duly provided for, semi-annually in arrears on the April 1 and October 1 in each year, commencing April 1, 2004, at the
per annum Interest Rate set forth above, until the principal hereof is paid or made available for payment. No interest shall accrue on the Maturity Date, so long as the principal amount of this Note
is paid on the Maturity Date. The interest so payable and punctually paid or duly provided for on any such Interest Payment Date (except for interest payable on the Maturity Date set forth above or,
if applicable, upon acceleration) will, as provided in the Indenture (as defined below), be paid to the Person in whose name this Note is registered at the close of business on the Regular Record Date
for such interest, which shall be the March 15 or September 15, as the case may be, next preceding such Interest Payment Date; provided that the first Interest Payment Date for any part
of this Note, the Original Issue Date of which is after a Regular Record Date but prior to the applicable Interest Payment Date, shall be the Interest Payment Date following the next succeeding
Regular Record Date; and provided that interest payable on the Maturity Date set forth above or, if applicable, upon acceleration, shall be payable to the Person to whom principal shall be payable.
Except as otherwise provided in the Indenture, any such interest not so punctually paid or duly provided for shall forthwith cease to be payable to the Holder on such Regular Record Date and shall be
paid to the Person in whose name this Note is registered at the close of business on a Special Record Date for the payment of such defaulted interest to be fixed by the Trustee, notice whereof shall
be given to Noteholders not more than fifteen days or fewer than ten days prior to such Special Record Date. Payment of the principal of and interest on this Note shall be payable pursuant to
Section 2.12(a) of the Indenture. 





 



        This
Note is a Global Note in respect of a duly authorized issue of 4.65% Senior Secured Notes due 2013 (the "NOTES OF THIS SERIES", which term includes any Global Notes representing
such Notes) of the Company issued and to be issued under an Indenture dated as of August 15, 2002, between the Company and The Bank of New York, as trustee (the "TRUSTEE", which term includes
any successor Trustee under the Indenture) and indentures supplemental thereto (collectively, the "INDENTURE"). Under the Indenture, one or more series of notes may be issued and, as used herein, the
term "Notes" refers to the Notes of this Series and any other outstanding series of Notes. Reference is hereby made to the Indenture for a more complete statement of the respective rights, limitations
of rights, duties and immunities thereunder of the Company, the Trustee and the Noteholders and of the terms upon which the Notes are and are to be authenticated and delivered. This Note has been
issued in respect of the series designated on the first page hereof in the aggregate principal amount of $200,000,000. 


        Prior
to the Release Date (as hereinafter defined), the Notes will be secured by first mortgage bonds (the "SENIOR NOTE FIRST MORTGAGE BONDS") delivered by the Company to the Trustee for
the benefit of the Holders of the Notes, issued under the Indenture of Mortgage or Deed of Trust, dated June 15, 1937, from the Company to The Bank of New York, as successor trustee (the
"MORTGAGE TRUSTEE"), as supplemented and modified (collectively, the "FIRST MORTGAGE"). Reference is made to the First Mortgage and the Indenture for a description of the rights of the Trustee as
holder of the Senior Note First Mortgage Bonds, the property mortgaged and pledged, the nature and extent of the security and the rights of the holders of first mortgage bonds, under the First
Mortgage and the rights of the Company and of the Mortgage Trustee in respect thereof, the duties and immunities of the Mortgage Trustee and the terms and conditions upon which the Senior Note First
Mortgage Bonds are secured and the circumstances under which additional first mortgage bonds may be issued. 


        From
and after such time as all first mortgage bonds (other than Senior Note First Mortgage Bonds) issued under the First Mortgage have been retired through payment, redemption or
otherwise at, before or after the maturity thereof (the "Release Date"), the Senior Note First Mortgage Bonds shall cease to secure the Notes in any manner. In certain circumstances prior to the
Release Date as provided in the Indenture, the Company is permitted to reduce the aggregate principal amount of a series of Senior Note First Mortgage Bonds held by the Trustee, but in no event prior
to the Release Date to an amount less than the aggregate outstanding principal amount of the series of Notes initially issued contemporaneously with such Senior Note First Mortgage Bonds. 


        Each
Note of this Series shall be dated and issued as of the date of its authentication by the Trustee and shall bear an Original Issue Date. Each Note issued upon transfer, exchange or
substitution of such Note shall bear the Original Issue Date of such transferred, exchanged or substituted Note, as the case may be. 


        The
Notes of this Series are not redeemable by the Company prior to the Maturity Date. 


        Interest
payments for this Note shall be computed and paid on the basis of a 360-day year of twelve 30-day months (and for any partial periods shall be calculated
on the basis of the number of days elapsed in a 360-day year of twelve 30-day months). If any Interest Payment Date or date on which the principal of this Note is required to
be paid is not a Business Day, then payment of principal or interest need not be made on such date but may be made on the next succeeding Business Day with the same force and effect as if made on such
Interest Payment Date or date on which the principal of this Note is required to be paid and, in the case of timely payment thereof, no interest shall accrue for the period from and after such
Interest Payment Date or the date on which the principal of this Note is required to be paid. 


        The
Company, at its option, and subject to the terms and conditions provided in the Indenture, will be discharged from any and all obligations in respect of the Notes (except for certain
obligations 


2





 



including
obligations to register the transfer or exchange of Notes, replace stolen, lost or mutilated Notes, maintain paying agencies and hold monies for payment in trust, all as set forth in the
Indenture) if the Company deposits with the Trustee money, U.S. Government Obligations which through the payment of interest thereon and principal thereof in accordance with their terms will provide
money, or a combination of money and U.S. Government Obligations, in any event in an amount sufficient, without reinvestment, to pay all the principal of and any premium and interest on the Notes on
the dates such payments are due in accordance with the terms of the Notes. 


        If
an Event of Default shall occur and be continuing, the principal of and interest on the Notes may be declared due and payable in the manner and with the effect provided in the
Indenture and, upon such declaration, the Trustee shall demand the redemption of the Senior Note First Mortgage Bonds to the extent provided in the Indenture. 


        The
Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modifications of the rights and obligations of the Company and the rights of the
Noteholders under the Indenture at any time by the Company and the Trustee with the consent of the Holders of not less than a majority in principal amount of the outstanding Notes. Any such consent or
waiver by the Holder of this Note shall be conclusive and binding upon such Holder and upon all future Holders of this Note and of any Note issued upon the registration of transfer hereof or in
exchange therefor or in lieu thereof whether or not notation of such consent or waiver is made upon this Note. 



        As
set forth in and subject to the provisions of the Indenture, no Holder of any Notes will have any right to institute any proceeding with respect to the Indenture or for any remedy
thereunder unless such Holder shall have previously given to the Trustee written notice of a continuing Event of Default with respect to such Notes, the Holders of not less than a majority in
principal amount of the outstanding Notes affected by such Event of Default shall have made written request and offered reasonable indemnity to the Trustee to institute such proceeding as Trustee and
the Trustee shall have failed to institute such proceeding within 60 days; provided that such limitations do not apply to a suit instituted by the Holder hereof for the enforcement of payment
of the principal of, or interest on, this Note on or after the respective due dates expressed here. 



        No
reference herein to the Indenture and to provisions of this Note or of the Indenture shall alter or impair the obligation of the Company, which is absolute and unconditional, to pay
the principal of, and
interest on, this Note at the times, places and rates and the coin or currency prescribed in the Indenture. 


        As
provided in the Indenture and subject to certain limitations therein set forth, this Note may be transferred only as permitted by the legend hereto and the provisions of the
Indenture. 


        The
Indenture and the Notes shall be governed by, and construed in accordance with, the laws of the State of New York without regard to conflicts of law principles thereof. 



        Unless
the certificate of authentication hereon has been executed by the Trustee, directly or through an Authenticating Agent by manual signature of an authorized officer, this Note
shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose. 


        All
terms used in this Note which are defined in the Indenture shall have the meanings assigned to them in the Indenture unless otherwise indicated herein. 


3





 

        IN
WITNESS WHEREOF, the Company has caused this instrument to be duly executed. 



	 	UNION ELECTRIC COMPANY
	

 	

By:	

/s/  JERRE E. BIRDSONG      

	 	 	 
	 	Title:	Vice President and Treasurer

	 	 	 
	 	Attest:	/s/  RONALD K. EVANS      

	 	 	 
	 	Title:	Assistant Secretary

	 	 	 
	TRUSTEE'S CERTIFICATE OF AUTHENTICATION	 	 
	 	 	 
	Dated: October 7, 2003	 	 
	 	 	 
	This Note is one of the Notes of the series herein designated, described or provided for in the within-

mentioned Indenture.	 	 
	 	 	 
	The Bank of New York, As Trustee	 	 
	
	 	 





	By:	 	/s/  ROBERT J. DUNN      
Authorized Signatory	 	 




4





 
 
 

ABBREVIATIONS    
    


        The following abbreviations, when used in the inscription on the face of this instrument, shall be construed as though they were written out in full according to
applicable laws or regulations: 



	TEN COM—as tenants in common	 	UNIF GIFT	 	 	 	 
	 	 	MIN ACT—	 	
	Custodian	

	 	 	 	 	(Cust)	 	(Minor)
	 	 	 	 	 	 	 
	TEN ENT—as tenants by the entireties	 	Under Uniform Gifts to Minors
	 	 	 	 	 	 	 
	JT TEN—as joint tenants with right of survivorship and not as tenants in common	 	
 State






Additional abbreviations may also be used

though not in the above list. 




FOR
VALUE RECEIVED the undersigned hereby sell(s),

assign(s) and transfer(s) unto 



	PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE	 	 
	 	 	 
	

	 	 	 
	

	 	 	 
	
 Please print or typewrite name and address including postal zip code of assignee
	 	 	 
	
 the within note and all rights thereunder, hereby irrevocably constituting and appointing attorney to transfer said note on the books of the Company, with full power of substitution in the
premises.	 	 
	Dated:                         	 	 
	 	 	 
	 	 	
 NOTICE: The signature to this assignment must correspond with the name as written upon the face of the within instrument in every particular, without alteration or enlargement or any change
whatever.
	 	 	 
	 	 	Signature(s) must be guaranteed by a financial institution that is a member of the Securities Transfer Agents Medallion Program ("STAMP"), the Stock Exchange Medallion Program ("SEMP") or the New York Stock Exchange,
 Inc. Medallion Signature Program ("MSP").




5









QuickLinks



Exhibit 4.3


ABBREVIATIONS