Document:

EX-4.3

 Exhibit 4.3 
  

			
	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. 
 Illinois Commerce Commission ID Nos.: Ill. C.C. No. 6691, No. 6671 and
No. 6672 
 AMEREN ILLINOIS COMPANY 

4.15% SENIOR SECURED NOTE DUE 2046 
  

			
	CUSIP: 02361D AQ3	  	NUMBER: 1
	ISIN: US02361D AQ34	  	
		
	ORIGINAL ISSUE DATE: December 14, 2015	  	PRINCIPAL AMOUNT: $250,000,000
		
	INTEREST RATE: 4.15%	  	MATURITY DATE: March 15, 2046

 AMEREN ILLINOIS COMPANY, a corporation of the State of Illinois (the “COMPANY”), for value received
hereby promises to pay to CEDE & CO. or registered assigns, the principal sum of TWO HUNDRED FIFTY MILLION DOLLARS ($250,000,000) 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 March 15 and September 15 in each year, commencing March 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 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 1 or September 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 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 4.15% Senior Secured Notes due 2046 (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 June 1, 2006 between the Company (as successor to Illinois Power Company) and The Bank of New York Mellon Trust
Company, N.A., 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 $250,000,000. 
 The Notes will be secured by first
mortgage bonds (the “SENIOR NOTE MORTGAGE BONDS”) delivered by the Company to the Trustee for the benefit of the Holders of the Notes, issued under the General Mortgage Indenture and Deed of Trust, dated as of November 1, 1992 between
the Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (the “MORTGAGE TRUSTEE”), as supplemented and modified (collectively, the “MORTGAGE”). Reference is made to the Mortgage and the Indenture for
a description of the rights of the Trustee as holder of the Senior Note 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 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 Mortgage Bonds are secured and the circumstances under which additional first
mortgage bonds may be issued. 
 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. 

  
 2 

 The Notes of this Series shall be issued in minimum denominations of $2,000 and integral
multiples of $1,000 in excess thereof. 
 Interest on this Note will accrue from and including the Original Issue Date specified above to,
but excluding, March 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 September 15, 2045 (six 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 that 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 September 15, 2045, six months prior to the Maturity Date (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 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 September 15, 2045 (six months prior to the Maturity Date) will be equal to 100% of the principal amount of the Notes of
this Series being redeemed on that redemption date plus accrued and unpaid interest thereon to the redemption date. The redemption price shall be payable to the Person to whom principal shall be payable except that 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 September 15, 2045, 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 registered in the name of The Depository Trust
Company (“DTC”), or its nominee, beneficial interests in such global certificates will be selected for redemption by DTC 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 date fixed for such redemption, of money sufficient to pay the principal of, 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. 

  
 3 

 “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 of this Series matured on September 15, 2045, six months prior to the Maturity Date) 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. 
 “REFERENCE TREASURY
DEALER” means (A) BNP Paribas Securities Corp., Goldman, Sachs & Co., TD Securities (USA) LLC and a Primary Treasury Dealer (as defined below) selected by each of Mitsubishi UFJ Securities (USA), Inc. and SunTrust Robinson
Humphrey, 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. 

  
 4 

 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, 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 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 a majority
in aggregate 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 a majority in aggregate 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, 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. 

  
 5 

 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. 

  
 6 

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

 

			
	AMEREN ILLINOIS COMPANY
		
	By:	 	    /s/ Ryan J. Martin
		 	    Ryan J. Martin
	Title:	 	    Assistant Vice President and Treasurer
		
	Attest:	 	    /s/ Craig W. Stensland
		 	    Craig W. Stensland
	Title:	 	    Assistant Secretary

 TRUSTEE’S CERTIFICATE 

OF AUTHENTICATION 
 Dated: December 14, 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:	 	/s/ Valère Boyd
		 	Authorized Signatory

  
 7 

 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”)EX-4.5

 Exhibit 4.5 

WHEN RECORDED MAIL TO: 
 Ameren Illinois Company 

Craig W. Stensland 
 One Ameren Plaza (MC 1310) 

1901 Chouteau Avenue 
 St. Louis, MO 63103 

AMEREN ILLINOIS COMPANY 

(SUCCESSOR TO ILLINOIS POWER COMPANY) 

TO 
 THE BANK OF NEW
YORK MELLON TRUST COMPANY, N.A. 
 AS SUCCESSOR TRUSTEE TO 

HARRIS TRUST AND SAVINGS BANK 
  

 
 SUPPLEMENTAL
INDENTURE 
 DATED AS OF DECEMBER 1, 2015 

TO 
 GENERAL MORTGAGE
INDENTURE AND DEED OF TRUST 
 DATED AS OF NOVEMBER 1, 1992 

 
  

This instrument was prepared by Gregory L. Nelson, Esq., Senior Vice President, General Counsel and Secretary of Ameren Illinois Company c/o Ameren
Corporation, One Ameren Plaza, 1901 Chouteau Avenue, St. Louis, Missouri 63103. 
  

 

 SUPPLEMENTAL INDENTURE dated as of December 1, 2015 (this “Supplemental
Indenture”), made by and between AMEREN ILLINOIS COMPANY (formerly named Central Illinois Public Service Company (“CIPS”) and successor to Illinois Power Company (“IP”) pursuant to the Merger, as defined
below), a corporation organized and existing under the laws of the State of Illinois (hereinafter sometimes called the “Company”), party of the first part, and THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., a national banking
association organized and existing under the laws of the United States, as successor trustee to Harris Trust and Savings Bank, as Trustee (the “Trustee”) under the General Mortgage Indenture and Deed of Trust dated as of
November 1, 1992, hereinafter mentioned, party of the second part; 
 WHEREAS, the Company has heretofore executed and delivered
its General Mortgage Indenture and Deed of Trust dated as of November 1, 1992 as from time to time amended and supplemented (the “Indenture”), to the Trustee, for the security of the Bonds issued and to be issued thereunder
(the “Bonds”); and 
 WHEREAS, as of 12:01 a.m. Central Time (the “Effective Time”) on
October 1, 2010, pursuant to the Agreement and Plan of Merger dated as of April 13, 2010 among CIPS, IP and Central Illinois Light Company (“CILCO”), IP and CILCO were merged with and into the Company (the
“Merger”) whereby the Company is the surviving corporation; and 
 WHEREAS, pursuant to Sections 13.01 and 14.01(a)
of the Indenture, the Company and the Trustee executed the Supplemental Indenture dated as of October 1, 2010 whereby, among other things, the Company (a) assumed the due and punctual payment of the principal of and premium, if any, and
interest, if any, on all of the Bonds then Outstanding and the performance and observance of every covenant and condition of the Indenture to be performed or observed by IP and (b) subjected to the Lien of the Indenture all equipment and
fixtures (other than Excepted Property, which is expressly excepted and excluded from the Lien of the Indenture) that were owned by CIPS immediately prior to the Effective Time and were of the same kind and character as the Mortgaged Property
immediately prior to the Effective Time; and 
 WHEREAS, pursuant to Sections 13.02 and 14.01(a)(i) of the Indenture, the Company has
succeeded to, and has been substituted for, and may exercise every right and power of, IP under the Indenture with the same effect as if the Company had been named the “Company” in the Indenture; and 

WHEREAS, pursuant to Section 14.01(a) of the Indenture, the Company and the Trustee executed 59 Supplemental Indentures dated
as of January 15, 2011 subjecting to the Lien of the Indenture certain real property that was owned by CIPS immediately prior to the Merger; and 

WHEREAS, pursuant to the terms and provisions of the Indenture there were created and authorized by supplemental indentures thereto
bearing the following dates, respectively, the Mortgage Bonds of the series issued thereunder and respectively identified opposite such dates: 
  

					
	 DATE OF
SUPPLEMENTAL
INDENTURE
	  	 IDENTIFICATION OF SERIES
	  	 CALLED

			
	 February 15, 1993
	  	8% Series due 2023 (redeemed)	  	Bonds of the 2023 Series
			
	 March 15, 1993
	  	6 1/8% Series due 2000 (paid at maturity)	  	Bonds of the 2000 Series
			
	 March 15, 1993
	  	6 3/4% Series due 2005 (paid at maturity)	  	Bonds of the 2005 Series
			
	 July 15, 1993
	  	7 1/2% Series due 2025 (redeemed)	  	Bonds of the 2025 Series
			
	 August 1, 1993
	  	6 1/2% Series due 2003 (paid at maturity)	  	Bonds of the 2003 Series
			
	 October 15, 1993
	  	5 5/8% Series due 2000 (paid at maturity)	  	Bonds of the Second 2000 Series

					
	 DATE OF
SUPPLEMENTAL
INDENTURE
	  	 IDENTIFICATION OF SERIES
	  	 CALLED

			
	 November 1, 1993
	  	Pollution Control Series M (redeemed)	  	Bonds of the Pollution Control Series M
			
	 November 1, 1993
	  	Pollution Control Series N (redeemed)	  	Bonds of the Pollution Control Series N
			
	 November 1, 1993
	  	Pollution Control Series O (redeemed)	  	Bonds of the Pollution Control Series O
			
	 April 1, 1997
	  	Pollution Control Series P (retired)	  	Bonds of the Pollution Control Series P
			
	 April 1, 1997
	  	Pollution Control Series Q (retired)	  	Bonds of the Pollution Control Series Q
			
	 April 1, 1997
	  	Pollution Control Series R (retired)	  	Bonds of the Pollution Control Series R
			
	 March 1, 1998
	  	Pollution Control Series S (redeemed)	  	Bonds of the Pollution Control Series S
			
	 March 1, 1998
	  	Pollution Control Series T (redeemed)	  	Bonds of the Pollution Control Series T
			
	 July 15, 1998
	  	6 1/4% Series due 2002 (paid at maturity)	  	Bonds of the 2002 Series
			
	 September 15, 1998
	  	6% Series due 2003 (paid at maturity)	  	Bonds of the Second 2003 Series
			
	 June 15, 1999
	  	7.50% Series due 2009 (paid at maturity)	  	Bonds of the 2009 Series
			
	 July 15, 1999
	  	Pollution Control Series U	  	Bonds of the Pollution Control Series U
			
	 July 15, 1999
	  	Pollution Control Series V (redeemed)	  	Bonds of the Pollution Control Series V
			
	 May 1, 2001
	  	Pollution Control Series W (retired)	  	Bonds of the Pollution Control Series W
			
	 May 1, 2001
	  	Pollution Control Series X (retired)	  	Bonds of the Pollution Control Series X
			
	 July 1, 2002
	  	10 5/8% Series due 2007 (not issued)	  	Bonds of the 2007 Series
			
	 July 1, 2002
	  	10 5/8% Series due 2012 (not issued)	  	Bonds of the 2012 Series
			
	 December 15, 2002
	  	11.50% Series due 2010 (redeemed)	  	Bonds of the 2010 Series
			
	 June 1, 2006
	  	Mortgage Bonds, Senior Notes Series AA (retired)	  	Bonds of Series AA
			
	 August 1, 2006
	  	Mortgage Bonds, 2006 Credit Agreement Series Bonds (retired)	  	2006 Credit Agreement Series Bonds

  
 2 

					
	 DATE OF
SUPPLEMENTAL
INDENTURE
	  	 IDENTIFICATION OF SERIES
	  	 CALLED

			
	 March 1, 2007
	  	Mortgage Bonds, 2007 Credit Agreement Series Bonds (retired)	  	2007 Credit Agreement Series Bonds
			
	 November 15, 2007
	  	Mortgage Bonds, Senior Notes Series BB	  	Bonds of Series BB
			
	 April 1, 2008
	  	Mortgage Bonds, Senior Notes Series CC	  	Bonds of Series CC
			
	 October 1, 2008
	  	Mortgage Bonds, Senior Notes Series DD	  	Bonds of Series DD
			
	 June 15, 2009
	  	Mortgage Bonds, 2009 Credit Agreement Series Bonds (retired)	  	2009 Credit Agreement Series Bonds
			
	 October 1, 2010
	  	Mortgage Bonds, Senior Notes Series CIPS-AA	  	Series CIPS-AA Mortgage Bonds
			
	 October 1, 2010
	  	Mortgage Bonds, Senior Notes Series CIPS-BB (retired)	  	Series CIPS-BB Mortgage Bonds
			
	 October 1, 2010
	  	Mortgage Bonds, Senior Notes Series CIPS-CC	  	Series CIPS-CC Mortgage Bonds
			
	 August 1, 2012
	  	First Mortgage Bonds, Senior Notes Series EE	  	Bonds of Series EE
			
	 December 1, 2013
	  	First Mortgage Bonds, Senior Notes Series FF	  	Bonds of Series FF
			
	 June 1, 2014
	  	First Mortgage Bonds, Senior Notes Series GG	  	Bonds of Series GG
			
	 December 1, 2014
	  	First Mortgage Bonds, Senior Notes Series HH	  	Bonds of Series HH

 and 

WHEREAS, a supplemental indenture with respect to the Bonds of the 2007 Series and the Bonds of the 2012 Series listed above
was executed and filed but such Bonds of the 2007 Series and Bonds of the 2012 Series were never issued and a release with respect to such supplemental indenture was subsequently executed and filed; and 

WHEREAS, pursuant to Section 14.01(a) of the Indenture, the Company elects to subject to the Lien of the Indenture certain
franchises, permits, licenses, easements and rights of way; and 
 WHEREAS, the Company desires to create a new series of
Bonds to be issued under the Indenture to be known as “First Mortgage Bonds, Senior Notes Series II” (the “Series II Mortgage Bonds”); and 

WHEREAS, the Company (as successor to IP) has entered into an Indenture dated as of June 1, 2006 (as amended and supplemented, the
“Senior Note Indenture”) with The Bank of New York Mellon Trust Company, N.A., as trustee (the “Senior Note Trustee”), providing for the issuance from time to time of senior notes thereunder; and 

WHEREAS, the Company desires by this Supplemental Indenture to issue to the Senior Note Trustee the Series II Mortgage Bonds as
security for $250,000,000 aggregate principal amount of the Company’s 4.15% Senior Secured Notes due 2046 (the “Senior Notes”) to be issued under the Senior Note Indenture; and 

WHEREAS, the Company, in the exercise of the powers and authority conferred upon and reserved to it under the provisions of the
Indenture, and pursuant to appropriate resolutions of the Board of Directors, has duly resolved and determined to make, execute and deliver to the Trustee this Supplemental Indenture in the form hereof for the purposes herein provided; and 

  
 3 

 WHEREAS, all conditions and requirements necessary to make this Supplemental Indenture a
valid, binding and legal instrument have been done, performed and fulfilled and the execution and delivery hereof have been in all respects duly authorized; 

NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH: 

THAT the Company, in consideration of the purchase and ownership from time to time of the Bonds and the service by the Trustee, and its
successors, under the Indenture and of One Dollar to it duly paid by the Trustee at or before the ensealing and delivery of these presents, the receipt of which is hereby acknowledged, hereby covenants and agrees to and with the Trustee and its
successors in trust under the Indenture, for the benefit of those who shall hold Bonds, as follows: 
 ARTICLE I 

DESCRIPTION OF THE SERIES II MORTGAGE BONDS 

Section 1. The Company hereby creates a new series of Bonds to be known as “First Mortgage Bonds, Senior Notes Series II” (the
“Series II Mortgage Bonds”). The Series II Mortgage Bonds shall be executed, authenticated and delivered in accordance with the provisions of, and shall in all respects be subject to, all of the terms, conditions and covenants
of the Indenture, as supplemented and modified. The Series II Mortgage Bonds shall be issued in the name of the Senior Note Trustee under the Senior Note Indenture to secure any and all of the Company’s obligations under the Senior Notes
and any other series of senior notes from time to time outstanding under the Senior Note Indenture. 
 The Series II Mortgage Bonds shall be
dated as provided in Section 3.03 of Article Three of the Indenture. The Series II Mortgage Bonds shall mature on March 15, 2046, shall accrue interest from the dates set forth in the Senior Notes and shall bear interest at the
same rate of interest as the Senior Notes. Interest on the Series II Mortgage Bonds is payable on the same dates as interest on the Senior Notes is paid, until the principal sum is paid in full. 

Upon any payment of the principal of, premium, if any, and interest on, all or any portion of the Senior Notes, whether at maturity or prior
to maturity by redemption or otherwise or upon provision for the payment thereof having been made in accordance with Section 5.01(a) of the Senior Note Indenture, the Series II Mortgage Bonds in a principal amount equal to the principal
amount of such Senior Notes shall, to the extent of such payment of principal, premium, if any, and interest, be deemed paid and the obligation of the Company thereunder to make such payment shall be discharged to such extent and, in the case of the
payment of principal (and premium, if any), such Series II Mortgage Bonds shall be surrendered to the Company for cancellation as provided in Section 4.08 of the Senior Note Indenture. The Trustee may at any time and all times conclusively
assume that the obligation of the Company to make payments with respect to the principal of, premium, if any, and interest on the Senior Notes, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to
the foregoing sentence unless and until the Trustee shall have received a written notice from the Senior Note Trustee signed by one of its officers stating (i) the timely payment of principal, or premium, if any, or interest on, the Senior
Notes has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the Senior Note Trustee pursuant to the Senior Note Indenture, and (iii) the amount of the arrearage. 

Section 2. The Series II Mortgage Bonds and the Trustee’s Certificate of Authentication shall be substantially in the following
forms respectively: 
 [FORM OF FACE OF BOND]

NOTWITHSTANDING ANY PROVISIONS HEREOF OR IN THE INDENTURE THIS BOND IS NOT ASSIGNABLE OR TRANSFERABLE EXCEPT AS PERMITTED BY SECTION 4.04
OF THE INDENTURE DATED AS OF JUNE 1, 2006, AS AMENDED AND SUPPLEMENTED, BETWEEN AMEREN ILLINOIS COMPANY AND THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., AS TRUSTEE 

  
 4 

 AMEREN ILLINOIS COMPANY 

(Incorporated under the laws of the State of Illinois) 

Illinois Commerce Commission 

Identification No.: Ill. C.C. No. 6691 or Ill. C.C. No. 6692 

FIRST MORTGAGE BOND, SENIOR NOTES SERIES II 
  

					
	 No.
	  	$
	                
	  

 AMEREN ILLINOIS COMPANY, a corporation organized and existing under the laws of the State of Illinois (the
“Company”), which term shall include any Successor Corporation as defined in the Indenture hereinafter referred to, for value received, hereby promises to pay to The Bank of New York Mellon Trust Company, N.A., as trustee (the
“Senior Note Trustee”) under the Indenture dated as of June 1, 2006 (as amended and supplemented, the “Senior Note Indenture”), relating to the Company’s 4.15% Senior Secured Notes due 2046 (the
“Senior Notes”) in the aggregate principal amount of $            , between the Company and the Senior Note Trustee, or registered assigns, the principal sum of
$            on March 15, 2046, in any coin or currency of the United States of America, which at the time of payment is legal tender for public and private debts, and to pay
interest thereon in like coin or currency from the date of issuance (and thereafter from the dates set forth in the Senior Notes), and at the same rate of interest as the Senior Notes. Interest on overdue principal, premium, if any, and, to the
extent permitted by law, on overdue interest, shall be payable at the interest rate payable on the Senior Notes. Interest on this Mortgage Bond is payable on the same dates as interest on the Senior Notes is paid, until the principal sum of
this Mortgage Bond is paid in full. Pursuant to Article IV of the Senior Note Indenture, this Mortgage Bond is issued to the Senior Note Trustee to secure any and all obligations of the Company under the Senior Notes and any other series
of senior notes from time to time outstanding under the Senior Note Indenture. Payment of principal of, or premium, if any, or interest on, the Senior Notes shall constitute payments on this Mortgage Bond as further provided herein and in the
Supplemental Indenture of December 1, 2015 (as hereinafter defined) pursuant to which this Mortgage Bond has been issued. Both the principal of, premium, if any, and the interest on, this Mortgage Bond are payable at the office of the Senior
Note Trustee. 
 Upon any payment of the principal of, premium, if any, and interest on, all or any portion of the Senior Notes, whether at
maturity or prior to maturity by redemption or otherwise or upon provision for the payment thereof having been made in accordance with Section 5.01(a) of the Senior Note Indenture, a principal amount of this Mortgage Bond equal to the
principal amount of such Senior Notes shall, to the extent of such payment of principal, premium, if any, and interest, be deemed paid and the obligation of the Company thereunder to make such payment shall be discharged to such extent and, in the
case of the payment of principal (and premium, if any), such Mortgage Bonds shall be surrendered to the Company for cancellation as provided in Section 4.08 of the Senior Note Indenture. The Trustee (as hereinafter defined) may at any time
and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of, premium, if any, and interest on, the Senior Notes, so far as such payments at the time have become due, has been fully satisfied
and discharged pursuant to the foregoing sentence unless and until the Trustee shall have received a written notice from the Senior Note Trustee signed by one of its officers stating (i) that timely payment of principal of, premium, if any, or
interest on, the Senior Notes has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the Senior Note Trustee pursuant to the Senior Note Indenture, and (iii) the amount of the arrearage. 

For purposes of Section 4.09 of the Senior Note Indenture, this Mortgage Bond shall be deemed to be the “Related Series of
Senior Note Mortgage Bonds” in respect of the Senior Notes. 
 This Mortgage Bond shall not be entitled to any benefit under the
Indenture or any indenture supplemental thereto, or become valid or obligatory for any purpose, until the form of certificate endorsed hereon shall have been signed by or on behalf of The Bank of New York Mellon Trust Company, N.A., as successor
trustee to Harris Trust and Savings Bank, the Trustee under the Indenture, or a successor trustee thereto under the Indenture (the “Trustee”). 

  
 5 

 The provisions of this Mortgage Bond are continued on the reverse hereof and such continued
provisions shall for all purposes have the same effect as though fully set forth at this place. 
 IN WITNESS WHEREOF, Ameren Illinois
Company has caused this Mortgage Bond to be signed (manually or by facsimile signature) in its name by an Authorized Executive Officer, as defined in the aforesaid Indenture, and attested (manually or by facsimile signature) by an Authorized
Executive Officer, as defined in such Indenture on the date hereof. 
 Dated: 

 

			
	AMEREN ILLINOIS COMPANY
		
	By:	 	 
		 	    AUTHORIZED EXECUTIVE OFFICER

  

			
	ATTEST:
		
	By:	 	 
		 	    AUTHORIZED EXECUTIVE OFFICER

 [FORM OF TRUSTEE’S CERTIFICATE OF AUTHENTICATION] 

This is one of the Mortgage Bonds of the series designated therein referred to in the within mentioned Indenture and the Supplemental
Indenture dated as of December 1, 2015. 
 THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A. 

as successor trustee to 
 Harris
Trust and Savings Bank, 
 TRUSTEE, 
  

			
	
		
	By:	 	 
		 	AUTHORIZED SIGNATORY

  
 6 

 [FORM OF REVERSE OF BOND] 

This Mortgage Bond is one of a duly authorized issue of Mortgage Bonds of the Company (the “Mortgage Bonds”) in unlimited
aggregate principal amount, of the series hereinafter specified, all issued and to be issued under and equally secured by the General Mortgage Indenture and Deed of Trust (as amended and supplemented, the “Indenture”), dated as of
November 1, 1992, executed by the Company (as successor to Illinois Power Company) to The Bank of New York Mellon Trust Company, N.A., as successor trustee to Harris Trust and Savings Bank (the “Trustee”) to which Indenture
reference is hereby made for a description of the properties mortgaged and pledged, the nature and extent of the security, the rights of registered owners of the Mortgage Bonds and of the Trustee in respect thereof, and the terms and conditions upon
which the Mortgage Bonds are, and are to be, secured. The Mortgage Bonds may be issued in series, for various principal sums, may mature at different times, may bear interest at different rates and may otherwise vary as provided in the
Indenture. This Mortgage Bond is one of a series designated as the Series II Mortgage Bonds of the Company, unlimited in aggregate principal amount, issued under and secured by the Indenture and described in the Supplemental Indenture dated as
of December 1, 2015 (the “Supplemental Indenture of December 1, 2015” ), between the Company and the Trustee, supplemental to the Indenture. 

This Series II Mortgage Bond is subject to redemption in accordance with the terms of Article II of the Supplemental Indenture of
December 1, 2015. 
 This Mortgage Bond shall be governed by and construed in accordance with the laws of the State of Illinois, except
to the extent that the law of any other jurisdiction shall be mandatorily applicable. 
 In case an Event of Default, as defined in the
Indenture, shall occur, the principal of all Mortgage Bonds at any such time outstanding under the Indenture may be declared or may become due and payable, upon the conditions and in the manner and with the effect provided in the Indenture. The
Indenture provides that such declaration may be rescinded under certain circumstances. 
 ARTICLE II 

REDEMPTION 

Section 1. The Series II Mortgage Bonds are not redeemable except on the date, in the principal amount and for the redemption price that
correspond to the redemption date for, the principal amount to be redeemed of, and the redemption price for, the Senior Notes, and except as set forth in Section 2 of this Article. 

In the event that the Company redeems any Senior Notes prior to maturity in accordance with the provisions of the Senior Note Indenture, the
Senior Note Trustee shall on the same date deliver to the Company the Series II Mortgage Bonds in principal amount corresponding to the Senior Notes so redeemed, as provided in Section 4.08 of the Senior Note Indenture. The Company agrees
to give the Trustee notice of any such redemption of the Senior Notes on or before the date fixed for any such redemption. 

Section 2. Upon the occurrence of an Event of Default under the Senior Note Indenture (as defined therein) and the acceleration of the
Senior Notes, the Series II Mortgage Bonds shall be redeemable in whole upon receipt by the Trustee (with a copy to the Company) of a written demand (hereinafter called a “II Redemption Demand”) from the Senior Note Trustee stating
that there has occurred under the Senior Note Indenture both an Event of Default and a declaration of acceleration of payment of principal, accrued interest and premium, if any, on the Senior Notes specifying the last date to which interest on such
Senior Notes has been paid (such date being hereinafter referred to as the “II Initial Interest Accrual Date”) and demanding redemption of the Series II Mortgage Bonds. The Company waives any right it may have to prior notice
of such redemption under the Indenture. Upon surrender of the Series II Mortgage Bonds by the Senior Note Trustee to the Trustee, the Series II Mortgage Bonds shall be redeemed at a redemption price equal to the principal amount thereof
plus accrued interest thereon from the II Initial Interest Accrual Date to the redemption date; provided, however, that in the event of a rescission or annulment of acceleration of the Senior Notes pursuant to the last paragraph of
Section 8.01(a) of the Senior Note Indenture, then any II Redemption Demand shall thereby be deemed to be rescinded by the Senior Note Trustee although no such rescission or annulment shall extend to or affect any subsequent default or
impair any right consequent thereon. 

  
 7 

 ARTICLE III 

ISSUE OF THE SERIES II MORTGAGE BONDS 

Section 1. The Company hereby exercises the right to obtain the authentication of $250,000,000 principal amount of additional Bonds
pursuant to the terms of Section 4.04 of the Indenture, all of which shall be Series II Mortgage Bonds. The principal amount of the Series II Mortgage Bonds outstanding from time to time shall always be equal to the principal amount of the
Senior Notes which are outstanding from time to time under the Senior Note Indenture and to the extent the Senior Note Trustee holds Series II Mortgage Bonds in excess of such principal amount, such Series II Mortgage Bonds shall be deemed cancelled
and retired and no longer outstanding under the Indenture. 
 Section 2. Such Series II Mortgage Bonds may be authenticated and
delivered prior to the filing for recordation of this Supplemental Indenture. 
 Section 3. For purposes of Section 4.09 of the
Senior Note Indenture, the Series II Mortgage Bonds shall be deemed to be the “Related Series of Senior Notes Mortgage Bonds” in respect of the Senior Notes. 

ARTICLE IV 
 THE TRUSTEE

 The Trustee hereby accepts the trusts hereby declared and provided, and agrees to perform the same upon the terms and conditions in
the Indenture set forth and upon the following terms and conditions: 
 The Trustee shall not be responsible in any manner whatsoever for or
in respect of the validity or sufficiency of this Supplemental Indenture or the due execution hereof by the Company or for or in respect of the recitals contained herein, all of which recitals are made by the Company solely. In general, each
and every term and condition contained in Article Eleven of the Indenture shall apply to this Supplemental Indenture with the same force and effect as if the same were herein set forth in full, with such omissions, variations and modifications
thereof as may be appropriate to make the same conform to this Supplemental Indenture. 
 ARTICLE V 

MISCELLANEOUS PROVISIONS 

Except as otherwise defined herein, capitalized terms defined in the Indenture are used herein as therein defined. This Supplemental Indenture
may be simultaneously executed in any number of counterparts, each of which when so executed shall be deemed to be an original; but such counterparts shall together constitute but one and the same instrument. 

  
 8 

 IN WITNESS WHEREOF, said Ameren Illinois Company has caused this Supplemental Indenture to be
executed on its behalf by an Authorized Executive Officer as defined in the Indenture, and its corporate seal to be hereto affixed and said seal and this Supplemental Indenture to be attested by an Authorized Executive Officer as defined in the
Indenture; and said The Bank of New York Mellon Trust Company, N.A., as successor trustee to Harris Trust and Savings Bank, in evidence of its acceptance of the trust hereby created, has caused this Supplemental Indenture to be executed on its
behalf by one of its Vice Presidents and this Supplemental Indenture to be attested by its Secretary or one of its Vice Presidents; all as of December 1, 2015. 

AMEREN ILLINOIS COMPANY 
 (CORPORATE SEAL)

  

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

  

			
	ATTEST:
		
	By:	 	                /s/ Craig W. Stensland
		 	Name:    Craig W. Stensland
		 	Title:    Assistant Secretary

  
 9 

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

successor trustee to 
 Harris Trust
and Savings Bank, 
 TRUSTEE, 
  

			
	
		
	By:	 	            /s/ Lawrence M. Kusch
		 	Name:    Lawrence M. Kusch
		 	Title:    Vice President

  

			
	ATTEST:
		
	By:	 	            /s/ Robert W. Hardy
		 	Name:    Robert W. Hardy
		 	Title:    Vice President

  
 10 

					
	 STATE OF MISSOURI
	 	 )
	  	
		 		  	ss.
	 CITY OF ST. LOUIS
	 	 )
	  	

 BE IT REMEMBERED, that on this 7th day of
December, 2015, before me, the undersigned, a Notary Public within and for the City and State aforesaid, personally came Ryan J. Martin, Assistant Vice President and Treasurer and Craig W. Stensland, Assistant Secretary, of Ameren Illinois Company,
a corporation duly organized, incorporated and existing under the laws of the State of Illinois, who are personally known to me to be such officers, and who are personally known to me to be the same persons who executed as such officers the within
instrument of writing, and such persons duly acknowledged that they signed, sealed and delivered the said instrument as their free and voluntary act as such officers and as the free and voluntary act of said Ameren Illinois Company for the uses and
purposes therein set forth. 
 IN WITNESS WHEREOF, I have hereunto subscribed my name and affixed my official seal on the day and year last
above written. 
  

	
	
	
	/s/ Carla J. Flinn
	NOTARY PUBLIC

 My Commission Expires on              

(NOTARIAL SEAL) 
  

	
	Carla J. Flinn – Notary Public
	Notary Seal, State of
	Missouri – St. Louis City
	Commission #14399906
	My Commission Expires: 4/20/2018

  
 11 

					
	 STATE OF ILLINOIS
	  	 )
	  	
		  		  	ss.
	 COUNTY OF COOK
	  	 )
	  	

 BE IT REMEMBERED, that on this 4th day of December, 2015, before me, the undersigned, a Notary Public within
and for the County and State aforesaid, personally came Lawrence M. Kusch, Vice President and Robert W. Hardy, Vice President, of The Bank of New York Mellon Trust Company, N.A., a national banking association duly organized, incorporated and
existing under the laws of the United States, who are personally known to me or proved to me on the basis of satisfactory evidence to be the same persons who executed as such officers the within instrument of writing, and such persons duly
acknowledged that they signed and delivered the said instrument as their free and voluntary act as such Vice President and Vice President, and as the free and voluntary act of said The Bank of New York Mellon Trust Company, N.A. for the uses and
purposes therein set forth. 
 IN WITNESS WHEREOF, I have hereunto subscribed my name and affixed my official seal on the day and year last
above written. 
  

			
	                “OFFICIAL SEAL”	  	
	                COLLEEN SKETCH	  	 /s/Colleen Sketch

	    NOTARY PUBLIC – STATE OF ILLINOIS	  	NOTARY PUBLIC
	MY COMMISSION EXPIRES MAY 20, 2017	  	

  

			
	My Commission Expires on 5/20/17	  	
	(NOTARIAL SEAL)	  	

  

			
	                COLLEEN SKETCH	  	
	NOTARY PUBLIC – STATE OF ILLINOIS	  	
	MY COMMISSION EXPIRES MAY 20, 2017	  	

  
 12

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