EX-4.3



 Exhibit 4.3 

AMEREN CORPORATION 

Company Order 

November 24, 2015 
 The
Bank of New York Mellon Trust Company, N.A., 
 as Trustee 
 2
North LaSalle Street, Suite 1020 
 Chicago, Illinois 60602 

Ladies and Gentlemen: 
 Application is hereby
made to The Bank of New York Mellon Trust Company, N.A., a national banking association, as successor trustee (the “Trustee”), under the Indenture, dated as of December 1, 2001, as amended and supplemented (the
“Indenture”), between Ameren Corporation, a Missouri corporation (the “Company”), and the Trustee for the authentication and delivery of $350,000,000 aggregate principal amount of the Company’s 2.700% Senior
Notes due 2020 (the “2020 Notes”) and $350,000,000 aggregate principal amount of the Company’s 3.650% Senior Notes due 2026 (the “2026 Notes,” and together with the 2020 Notes, the “Notes”),
pursuant to the provisions of Article II of the Indenture. The Company, at any time and from time to time, without the consent of the holders of the Notes, may deliver additional Notes of either or both of the same series executed by the Company to
the Trustee for authentication, having the same terms and conditions (including the same CUSIP number) as the applicable series of Notes authenticated pursuant hereto in all respects, except for the date of original issuance, the offering price, and
if applicable, the initial interest accrual date and the initial interest payment date. Such additional Notes shall be part of the same series as the applicable series of Notes authenticated pursuant hereto. All capitalized terms not defined herein
that are defined in the Indenture shall have the same meaning as used in the Indenture. 
 The Notes of each series will be registered under
the Securities Act of 1933, as amended, and issued in the form of a Global Note registered in the name of Cede & Co. (as nominee for The Depository Trust Company (“DTC”), New York, New York, which will act as the Depositary
for each Global Note). Pursuant to Section 2.05(c) of the Indenture, the 2020 Notes will have the terms set forth in the form of Global Note attached hereto as Exhibit A and the 2026 Notes will have the terms set forth in the form of Global
Note attached hereto as Exhibit B (which terms are incorporated by reference in this Company Order). The Global Notes shall bear the depositary legend in substantially the form set forth in Exhibit A and Exhibit B attached hereto. The Notes will be
issued only in denominations of $2,000 and in integral multiples of $1,000 in excess thereof. 







 In connection with this Company Order, there are delivered to you herewith the following: 

 

	 	1.	Certified copies of the resolutions adopted by the Finance Committee of the Board of Directors of the Company authorizing this Company Order and the issuance and sale of the Notes by the Company pursuant to
Section 2.05(c)(1) of the Indenture; 

  

	 	2.	Opinions of Counsel addressed to you or in which it is stated that you may rely pursuant to Sections 2.05(c)(2) and 15.05 of the Indenture; 


 

	 	3.	Officers’ Certificate pursuant to Sections 2.05(c)(3) and 15.05 of the Indenture; 

  

	 	4.	Global Note (No. R-1) representing the 2020 Notes executed on behalf of the Company in accordance with the terms of Section 2.05(a) of the Indenture, specifying the terms of the 2020 Notes (which terms are
incorporated by reference herein); and 

  

	 	5.	Global Note (No. R-1) representing the 2026 Notes executed on behalf of the Company in accordance with the terms of Section 2.05(a) of the Indenture, specifying the terms of the 2026 Notes (which terms are
incorporated by reference herein). 

 The Global Notes representing the Notes are to be held for delivery through the facilities of DTC to
Barclays Capital Inc. on behalf of the several underwriters thereof, against payment therefor at the closing in respect of the sale thereof, such closing to be held at 10:00 a.m., New York time, November 24, 2015, at the offices of Morgan,
Lewis & Bockius LLP, 101 Park Avenue, New York, New York 10178. You are hereby instructed to authenticate the Global Notes representing the Notes in the name of CEDE & Co. as registered holder and to hold the Global Notes as
custodian for DTC. 







 Please acknowledge receipt of the Global Notes representing the Notes, the instructions referred
to above and the supporting documentation pursuant to the Indenture referred to above. 
  

			
	
	Very truly yours,
	
	AMEREN CORPORATION
		
	By:	 	 /s/ Ryan J. Martin

		 	 Name: Ryan J. Martin
 Title: Assistant Vice
President and Treasurer



 Company Signature Page to Company Order 







 Receipt from the Company of the Global Notes representing the Notes, the instructions referred to
above and the supporting documentation pursuant to the Indenture in connection with the authentication and delivery of the Notes is hereby acknowledged. 
  

			
	 THE BANK OF NEW YORK MELLON
 TRUST
COMPANY, N.A.,
 as Trustee

		
	By:	 	 /s/ Valere Boyd

		 	 Name: Valere Boyd
 Title: Vice
President



 Trustee Signature Page to Company Order 







 EXHIBIT A 
  

			
	REGISTERED	  	REGISTERED

 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. 
 AMEREN CORPORATION 

2.700% SENIOR NOTE DUE 2020 
  

			
	CUSIP: 023608 AF9	  	NUMBER: R-l
		
	ORIGINAL ISSUE DATE: November 24, 2015	  	PRINCIPAL AMOUNT: $350,000,000
		
	INTEREST RATE: 2.700%	  	MATURITY DATE: November 15, 2020

 AMEREN CORPORATION, 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 THREE HUNDRED FIFTY MILLION DOLLARS ($350,000,000) on the Maturity Date set forth above, and to pay interest thereon from and including the Original Issue
Date specified above or from and including the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually in arrears on May 15 and November 15 in each year, commencing May 15, 2016, and on
the Maturity Date, 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 redemption or 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 May 1 or November 1 as the case may be, whether or not
a Business Day, 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 further, that interest payable on
the Maturity Date set forth above or, if applicable, upon redemption or 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 nor fewer than ten days prior to such Special Record Date. Payment of the principal of and interest and premium 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 2.700%
Senior Notes due 2020 (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 December 1, 2001 between the Company and The Bank
of New York (The Bank of New York Mellon Trust Company, N.A., successor), as trustee (herein called 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, issued in the initial aggregate principal amount of $350,000,000. 

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 of this Series 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. 

Interest on this Note will accrue from and including the Original Issue Date specified above to, but excluding May 15, 2016, and
thereafter, from and including each Interest Payment Date to, but excluding, the next succeeding Interest Payment Date, the Maturity Date or any redemption date, as the case may be. 

All or a portion of the Notes of this Series may be redeemed at the option of the Company at any time or from time to time. The redemption
price for the Notes of this Series to be redeemed on any redemption date prior to October 15, 2020 (one month prior to the Maturity Date) will be equal to the greater of the following amounts: (a) 100% of the principal amount of the Notes
of this Series being redeemed on the redemption date; or (b) the sum of the present values of the remaining scheduled payments of principal and interest on the Notes of this Series being redeemed on that redemption date that would be payable if
such Notes matured on October 15, 2020 (not including any portion of any payments of interest accrued to the redemption date) discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months)
at the Adjusted Treasury Rate (as defined below) plus 20 basis points, as determined by the Reference Treasury Dealer (as defined below), plus, in each 

  
 2 








 
case, accrued and unpaid interest thereon to the redemption date. The redemption price for the Notes of this Series to be redeemed on any redemption date on or after October 15, 2020 (one
month prior to the Maturity Date) will be equal to 100% of the principal amount of the Notes of this Series being redeemed on the redemption date plus accrued and unpaid interest thereon to the redemption date. Notwithstanding the foregoing,
installments of interest on Notes of this Series that are due and payable on Interest Payment Dates falling on or prior to a redemption date will be payable on the Interest Payment Date to the Holder of this Note as of the close of business on the
relevant Regular Record Date. 
 With respect to a redemption occurring prior to October 15, 2020, the Company shall give the Trustee
written notice of the redemption price promptly after the calculation thereof and the Trustee shall not be responsible for such calculation. 

The Company shall mail notice of any redemption at least 30 days but not more than 60 days before the redemption date to each Holder of the
Notes of this Series to be redeemed, and, if less than all Notes of this Series are to be redeemed, the particular Notes of this Series to be redeemed will be selected by the Trustee in such manner as it shall deem appropriate and fair; provided,
that as long as the Notes of this Series are represented by global certificates, beneficial interests in such global certificates will be selected for redemption by The Depository Trust Company in accordance with its standard procedures therefor.
Unless the Company defaults in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the Notes of this Series or portions thereof called for redemption. 

Any notice of redemption at the Company’s option may state that such redemption will be conditional upon receipt by the Trustee, on or
prior to the redemption date, of money sufficient to pay the principal of and premium, if any, and interest on, the Notes of this Series or portions thereof called for redemption, and that if such money has not been so received, such notice will be
of no force and effect and the Company will not be required to redeem such Notes or portions thereof. 
 “ADJUSTED TREASURY RATE”
means, with respect to any redemption date, the rate per annum equal to the semiannual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal
amount) equal to the Comparable Treasury Price for such redemption date. 
 “COMPARABLE TREASURY ISSUE” means the United States
Treasury security selected by the Reference Treasury Dealer as having a maturity comparable to the remaining term of the Notes of this Series to be redeemed (assuming, for this purpose, that the Notes matured on October 15, 2020) that would be
utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of such Notes of this Series. 

“COMPARABLE TREASURY PRICE” means, with respect to any redemption date, (A) the average of the Reference Treasury Dealer
Quotations for such redemption date, after excluding the highest and lowest of such Reference Treasury Dealer Quotations, or (B) if the Company obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such
quotations, or (C) if only one Reference Treasury Dealer Quotation is received, such quotation. 

  
 3 








 “REFERENCE TREASURY DEALER” means (A) Barclays Capital Inc., J.P. Morgan
Securities LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Mizuho Securities USA Inc. or, in each case, an affiliate thereof, which are primary U.S. Government securities dealers in the United States (each, a “Primary
Treasury Dealer”), and their respective successors; provided, however, that if any of the foregoing shall cease to be a Primary Treasury Dealer, the Company will substitute therefor another Primary Treasury Dealer; and (B) any other
Primary Treasury Dealer(s) selected by the Company. 
 “REFERENCE TREASURY DEALER QUOTATIONS” means, with respect to each
Reference Treasury Dealer and any redemption date, the average, as determined by the Company, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the
Company by such Reference Treasury Dealer at 5:00 p.m. (New York City time) on the third Business Day preceding such redemption date. 

Interest payments for this Note shall be computed and paid on the basis of a 360-day year consisting 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 falls on a day that is not a Business Day, the interest due on such Interest Payment Date will be
paid on the next succeeding Business Day (and without any interest or other payment in respect of any such delay). If the Maturity Date of this Note or any redemption date falls on a day that is not a Business Day, the payment of principal, premium,
if any, and interest will be made on the next succeeding Business Day with the same force and effect as if made on such Maturity Date or redemption date, and no interest on such payment shall accrue for the period from and after the Maturity Date or
such redemption date. 
 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 of this Series (except for certain obligations including obligations to register the transfer or exchange of Notes of this Series, replace stolen, lost or mutilated Notes of this Series, 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 of this Series on the
dates such payments are due in accordance with the terms of the Notes of this Series. 
 If an Event of Default shall occur and be
continuing with respect to the Notes of this Series, the principal of and interest on the Notes of this series may be declared due and payable in the manner and with the effect 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 

  
 4 








 
the Holders of a majority in aggregate principal amount of the outstanding Notes, considered as one class, provided that if a proposed amendment directly affects the rights of the Holders of
Notes of one or more, but less than all, of series of Outstanding Notes, then with the consent only of the Holders of a majority in aggregate principal amount of the Outstanding Notes of all series so directly affected, considered as one class. 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 a majority in aggregate principal amount of the Notes of all series then outstanding in respect of which an Event of Default has occurred and is continuing, considered as one class, 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, however, that such limitations do not apply to a suit instituted
by the Holder hereof for the enforcement of payment of the principal of and any premium or interest on this Note on or after the respective due dates expressed herein. 

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 any premium 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 that are defined in the Indenture shall have the meanings assigned to them in the Indenture unless otherwise
indicated herein. 

  
 5 








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

 

			
	AMEREN CORPORATION
		
	By:	 	  

		 	Ryan J. Martin
	Title:	 	Assistant Vice President and Treasurer
		
	Attest:	 	  

		 	Craig W. Stensland
	Title:	 	Assistant Secretary


 TRUSTEE’S CERTIFICATE OF AUTHENTICATION 

Dated: November 24, 2015 
 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 MELLON TRUST COMPANY, N.A., As
Trustee 
  

			
	By:	 	  

		 	Authorized Signatory


  
 6 








 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”)


  
 7 








 EXHIBIT B 
  

			
	REGISTERED	  	REGISTERED

 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. 
 AMEREN CORPORATION 

3.650% SENIOR NOTE DUE 2026 
  

			
	CUSIP: 023608 AG7	  	NUMBER: R-1
		
	ORIGINAL ISSUE DATE: November 24, 2015	  	PRINCIPAL AMOUNT: $350,000,000
		
	INTEREST RATE: 3.650%	  	MATURITY DATE: February 15, 2026

 AMEREN CORPORATION, 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 THREE HUNDRED FIFTY MILLION DOLLARS ($350,000,000) on the Maturity Date set forth above, and to pay interest thereon from and including the Original Issue
Date specified above or from and including the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually in arrears on February 15 and August 15 in each year, commencing February 15, 2016,
and on the Maturity Date, 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 redemption or 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 February 1 or August 1 as the case may be,
whether or not a Business Day, 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 further, that
interest payable on the Maturity Date set forth above or, if applicable, upon redemption or 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 nor fewer than ten days prior to such Special Record Date. Payment of the principal of and interest and premium 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 3.650% Senior Notes due 2026 (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 December 1, 2001 between the
Company and The Bank of New York (The Bank of New York Mellon Trust Company, N.A., successor), as trustee (herein called 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, issued in the initial aggregate principal amount of $350,000,000. 

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 of this Series 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. 

Interest on this Note will accrue from and including the Original Issue Date specified above to, but excluding February 15, 2016, and
thereafter, from and including each Interest Payment Date to, but excluding, the next succeeding Interest Payment Date, the Maturity Date or any redemption date, as the case may be. 

All or a portion of the Notes of this Series may be redeemed at the option of the Company at any time or from time to time. The redemption
price for the Notes of this Series to be redeemed on any redemption date prior to November 15, 2025 (three months prior to the Maturity Date) will be equal to the greater of the following amounts: (a) 100% of the principal amount of the
Notes of this Series being redeemed on the redemption date; or (b) the sum of the present values of the remaining scheduled payments of principal and interest on the Notes of this Series being redeemed on that redemption date that would be
payable if such Notes matured on November 15, 2025 (not including any portion of any payments of interest accrued to the redemption date) discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve
30-day months) at the Adjusted Treasury Rate (as defined below) plus 25 basis points, as determined by the Reference Treasury Dealer (as defined below), plus, in each 

  
 2 








 
case, accrued and unpaid interest thereon to the redemption date. The redemption price for the Notes of this Series to be redeemed on any redemption date on or after November 15, 2025 (three
months prior to the Maturity Date) will be equal to 100% of the principal amount of the Notes of this Series being redeemed on the redemption date plus accrued and unpaid interest thereon to the redemption date. Notwithstanding the foregoing,
installments of interest on Notes of this Series that are due and payable on Interest Payment Dates falling on or prior to a redemption date will be payable on the Interest Payment Date to the Holder of this Note as of the close of business on the
relevant Regular Record Date. 
 With respect to a redemption occurring prior to November 15, 2025, the Company shall give the Trustee
written notice of the redemption price promptly after the calculation thereof and the Trustee shall not be responsible for such calculation. 

The Company shall mail notice of any redemption at least 30 days but not more than 60 days before the redemption date to each Holder of the
Notes of this Series to be redeemed, and, if less than all Notes of this Series are to be redeemed, the particular Notes of this Series to be redeemed will be selected by the Trustee in such manner as it shall deem appropriate and fair; provided,
that as long as the Notes of this Series are represented by global certificates, beneficial interests in such global certificates will be selected for redemption by The Depository Trust Company in accordance with its standard procedures therefor.
Unless the Company defaults in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the Notes of this Series or portions thereof called for redemption. 

Any notice of redemption at the Company’s option may state that such redemption will be conditional upon receipt by the Trustee, on or
prior to the redemption date, of money sufficient to pay the principal of and premium, if any, and interest on, the Notes of this Series or portions thereof called for redemption, and that if such money has not been so received, such notice will be
of no force and effect and the Company will not be required to redeem such Notes or portions thereof. 
 “ADJUSTED TREASURY RATE”
means, with respect to any redemption date, the rate per annum equal to the semiannual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal
amount) equal to the Comparable Treasury Price for such redemption date. 
 “COMPARABLE TREASURY ISSUE” means the United States
Treasury security selected by the Reference Treasury Dealer as having a maturity comparable to the remaining term of the Notes of this Series to be redeemed (assuming, for this purpose, that the Notes matured on November 15, 2025) that would be
utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of such Notes of this Series. 

“COMPARABLE TREASURY PRICE” means, with respect to any redemption date, (A) the average of the Reference Treasury Dealer
Quotations for such redemption date, after excluding the highest and lowest of such Reference Treasury Dealer Quotations, or (B) if the Company obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such
quotations, or (C) if only one Reference Treasury Dealer Quotation is received, such quotation. 

  
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 “REFERENCE TREASURY DEALER” means (A) Barclays Capital Inc., J.P. Morgan
Securities LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Mizuho Securities USA Inc. or, in each case, an affiliate thereof, which are primary U.S. Government securities dealers in the United States (each, a “Primary
Treasury Dealer”), and their respective successors; provided, however, that if any of the foregoing shall cease to be a Primary Treasury Dealer, the Company will substitute therefor another Primary Treasury Dealer; and (B) any other
Primary Treasury Dealer(s) selected by the Company. 
 “REFERENCE TREASURY DEALER QUOTATIONS” means, with respect to each
Reference Treasury Dealer and any redemption date, the average, as determined by the Company, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the
Company by such Reference Treasury Dealer at 5:00 p.m. (New York City time) on the third Business Day preceding such redemption date. 

Interest payments for this Note shall be computed and paid on the basis of a 360-day year consisting 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 falls on a day that is not a Business Day, the interest due on such Interest Payment Date will be
paid on the next succeeding Business Day (and without any interest or other payment in respect of any such delay). If the Maturity Date of this Note or any redemption date falls on a day that is not a Business Day, the payment of principal, premium,
if any, and interest will be made on the next succeeding Business Day with the same force and effect as if made on such Maturity Date or redemption date, and no interest on such payment shall accrue for the period from and after the Maturity Date or
such redemption date. 
 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 of this Series (except for certain obligations including obligations to register the transfer or exchange of Notes of this Series, replace stolen, lost or mutilated Notes of this Series, 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 of this Series on the
dates such payments are due in accordance with the terms of the Notes of this Series. 
 If an Event of Default shall occur and be
continuing with respect to the Notes of this Series, the principal of and interest on the Notes of this series may be declared due and payable in the manner and with the effect 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 

  
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the Holders of a majority in aggregate principal amount of the outstanding Notes, considered as one class, provided that if a proposed amendment directly affects the rights of the Holders of
Notes of one or more, but less than all, of series of Outstanding Notes, then with the consent only of the Holders of a majority in aggregate principal amount of the Outstanding Notes of all series so directly affected, considered as one class. 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 a majority in aggregate principal amount of the Notes of all series then outstanding in respect of which an Event of Default has occurred and is continuing, considered as one class, 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, however, that such limitations do not apply to a suit instituted
by the Holder hereof for the enforcement of payment of the principal of and any premium or interest on this Note on or after the respective due dates expressed herein. 

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 any premium 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 that are defined in the Indenture shall have the meanings assigned to them in the Indenture unless otherwise
indicated herein. 

  
 5 








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

 

			
	AMEREN CORPORATION
		
	By:	 	  

		 	Ryan J. Martin
	Title:	 	Assistant Vice President and Treasurer
		
	Attest:	 	  

		 	Craig W. Stensland
	Title:	 	Assistant Secretary


 TRUSTEE’S CERTIFICATE OF AUTHENTICATION 

Dated: November 24, 2015 
 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 MELLON TRUST COMPANY, N.A., As
Trustee 
  

			
	By:	 	  

		 	Authorized Signatory


  
 6 








 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”)


  
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