Free Writing Prospectus - Filing Under Securities Act Rules 163/433 (fwp)

Filed Pursuant to Rule 433

Registration No. 333-249475-02

Ameren Illinois Company

Pricing Term Sheet

June 22, 2021

Issuer:		Ameren Illinois Company

Issue:		0.375% First Mortgage Bonds due 2023 (the “Bonds”)

Principal Amount:		$100,000,000

Coupon (Interest Rate):		0.375% per annum

Maturity Date:		June 15, 2023

Benchmark Treasury:		0.125% due May 31, 2023

Benchmark Treasury Price:		99-25

Benchmark Treasury Yield:		0.238%

Spread to Benchmark Treasury:		+15 basis points

Re-offer Yield:		0.388%

Offering Price (Issue Price):		99.975% of the principal amount

Interest Payment Dates:		June 15 and December 15, commencing December 15, 2021

Optional Redemption:		The Bonds will not be redeemable at the Issuer’s option before maturity

Expected Ratings (Moody’s/S&P)*:		A1 (stable) / A (stable)

Trade Date:		June 22, 2021

Settlement Date:		June 29, 2021 (T+5)**

CUSIP / ISIN:		02361D AW0 / US02361DAW02

Joint Book-Running Managers:

RBC Capital Markets, LLC

TD Securities (USA) LLC

Truist Securities, Inc.

Wells Fargo Securities, LLC

BNY Mellon Capital Markets, LLC

KeyBanc Capital Markets Inc.

U.S. Bancorp Investments, Inc.

Co-Managers:

Blaylock Van, LLC

CastleOak Securities, L.P.

Loop Capital Markets LLC

Penserra Securities LLC

In addition to the Bonds, the Issuer is concurrently offering $350 million principal amount of its 2.90% First Mortgage Bonds due 2051. The offerings are not contingent upon each other.

A security rating is not a recommendation to buy, sell or hold securities and should be evaluated independently of any other rating. The rating is subject to revision or withdrawal at any time by the assigning rating organization.

It is expected that delivery of the Bonds will be made against payment for the Bonds on or about the Settlement Date specified above, which will be the fifth business day following the date hereof. Under Rule 15c6-1 under the Securities Exchange Act of 1934, as amended, trades in the secondary market generally are required to settle in two business days, unless the parties to a trade expressly agree otherwise. Accordingly, purchasers who wish to trade the Bonds more than two business days prior to the scheduled settlement date will be required, by virtue of the fact that the Bonds initially are expected to settle in T+5, to specify an alternative settlement arrangement at the time of any such trade to prevent a failed settlement.

The Issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the Issuer has filed with the SEC for more complete information about the Issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC’s website at www.sec.gov. Alternatively, the Issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling RBC Capital Markets, LLC toll-free at 1-866-375-6829, TD Securities (USA) LLC toll-free at 1-855-495-9846, Truist Securities, Inc. toll-free at 1-800-685-4786 or Wells Fargo Securities, LLC toll-free at 1-800-645-3751.