Exhibit 4.3


 


AMEREN CORPORATION


 


Company Order


 


November 18, 2021


 


The Bank of New York Mellon Trust Company, N.A., 


as Trustee 


2 North LaSalle Street, Suite 700 


Chicago, Illinois 60602


 


Re:     1.95%
Senior Notes due 2027


 


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 $500,000,000
aggregate principal amount of the Company’s 1.95% Senior Notes due 2027 (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 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 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 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 will be 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 the Global Note). Pursuant to Section 2.05(c) of the Indenture, the
Notes will have the terms set forth in the form of Global Note attached hereto as Exhibit A (which terms are incorporated
by reference in this Company Order). The Global Note shall bear the depositary legend in substantially the form set forth in Exhibit A
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; and



 


		4.	Global Note (No. R-1) representing the 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 Notes (which terms are incorporated by reference
herein).



 


The Global Note representing the Notes is to be
held for delivery through the facilities of DTC to Morgan Stanley & Co. LLC, 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 18,
2021, at the offices of Morgan, Lewis & Bockius LLP, 101 Park Avenue, New York, New York 10178. You are hereby instructed to
authenticate the Global Note representing the Notes in the name of Cede & Co. as registered holder and to hold it as custodian
for DTC.


 






     


     


    

 


Please acknowledge receipt
of the Global Note 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/ Darryl T. Sagel
	 	 	 	Name: 	Darryl T. Sagel
	 	 	 	Title: 	Vice President and Treasurer



 


Company Signature Page to Company Order


 






     


     


    

 


Receipt from the Company of
the Global Note 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/ Robert W.
    Hardy
	 	 	 	Name: Robert W. Hardy
	 	 	 	Title: Vice President




 


Trustee Signature Page to Company Order