On May 12, 2021, Ameren Corporation (the “Company”)
entered into an Equity Distribution Sales Agreement (the “Sales Agreement”) with Barclays Capital Inc., BofA Securities, Inc.,
Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC, Mizuho Securities USA LLC, Morgan Stanley & Co. LLC, MUFG Securities
Americas Inc. and Wells Fargo Securities, LLC, as sales agents and as forward sellers (in such capacities as applicable, the “Agents”
and the “Forward Sellers”), and Bank of America, N.A., Barclays Bank PLC, Goldman Sachs & Co. LLC, JPMorgan Chase Bank,
National Association, New York Branch, Mizuho Markets Americas LLC, Morgan Stanley & Co. LLC, MUFG Securities EMEA plc and Wells Fargo
Bank, National Association, as forward purchasers (the “Forward Purchasers”), establishing an equity distribution program,
pursuant to which the Company, through the Agents, may offer and sell from time to time shares of the Company’s common stock, par
value $0.01 per share (the “Common Stock”), having an aggregate gross sales price of up to $750,000,000. The Company has no
obligation to offer or sell any Common Stock under the Sales Agreement and may at any time suspend offers under the Sales Agreement.
The Sales Agreement provides that, in addition
to the issuance and sale of shares of Common Stock by the Company to or through the Agents, the Company may enter into forward sale agreements
under the master forward confirmations executed by and between the Company and each of the Forward Purchasers on May 12, 2021, a
form of which is attached to the Sales Agreement as Exhibit C thereto (each, a “Master Forward Confirmation”), and related
supplemental confirmations to be entered into between the Company and the relevant Forward Purchaser pursuant thereto (collectively, the
“Forward Sale Agreement”). In connection with any Forward Sale Agreement, the relevant Forward Purchaser will borrow from
third parties and, through its affiliated Forward Seller, offer a number of shares of Common Stock equal to the number of shares of Common
Stock underlying the particular Forward Sale Agreement.
In no event will the aggregate number of shares
of Common Stock sold through the Agents or the Forward Sellers under the Sales Agreement and under any Forward Sale Agreement have an
aggregate gross sales price in excess of $750,000,000 (unless the Company increases such amount pursuant to the Sales Agreement).
The forward sale price per share under each Forward
Sale Agreement will initially equal the product of (1) an amount equal to one minus the applicable forward selling commission and (2)
the volume-weighted average price per share at which the borrowed shares of Common Stock were sold pursuant to the Sales Agreement by
the relevant Forward Seller. Thereafter, the forward sale price will be subject to adjustment as described in the Forward Sale Agreement.
The Forward Sale Agreements will provide that the forward sale price, as well as the sales prices used to calculate the initial forward
sale price, will be subject to increase or decrease based on a floating interest rate factor equal to the overnight bank funding rate,
less a spread, and subject to decrease by amounts related to expected dividends on the Common Stock during the term of the particular
Forward Sale Agreement. If the overnight bank funding rate is less than the spread for the particular Forward Sale Agreement on any day,
the interest factor will result in a daily reduction of the forward sale price.
The Company will not initially receive any
proceeds from the sale of borrowed shares of Common Stock by a Forward Seller; however, the Company will receive proceeds upon
future physical settlement of the relevant Forward Sale Agreement on dates specified by the Company on or prior to the maturity date
of the relevant Forward Sale Agreement. If the Company elects to physically settle any Forward Sale Agreement by issuing and
delivering shares of Common Stock, it will receive an amount of cash from the relevant Forward Purchaser equal to the product of the
forward sale price per share under such Forward Sale Agreement and the number of shares of Common Stock underlying such Forward Sale
Agreement subject to physical settlement.
Although the Company expects to settle any Forward
Sale Agreement with a full physical settlement, it may, except in limited circumstances, elect a cash or net share settlement for all
or a portion its obligations under such Forward Sale Agreement. If the Company elects to cash settle or net share settle a Forward Sale
Agreement, the Company may not (in the case of cash settlement) or will not (in the case of net share settlement) receive any proceeds,
and the Company may owe cash (in the case of cash settlement) or shares of Common Stock (in the case of net share settlement) to the relevant
Forward Purchaser.
Sales of shares of Common Stock under the equity
distribution program, if any, will be made (1) by any method permitted by law to be an “at the market offering” as defined
in Rule 415 under the Securities Act of 1933, as amended, including sales made directly on or through the New York Stock Exchange, or
on another market for the Common Stock, sales made to or through a market maker other than on an exchange, or through an electronic communications
network or (2) in privately negotiated transactions (if, and only if, the Company and the Agents, Forward Sellers and Forward Purchasers
party thereto have so agreed in writing). Any shares of Common Stock offered under the equity distribution program will be offered pursuant
to the Company’s Registration Statement on Form S-3 (No. 333-249475), which became effective upon filing.
The foregoing descriptions of the Sales Agreement
and the Master Forward Confirmations do not purport to be complete and are qualified in their entirety by reference to the Sales Agreement,
which is filed as Exhibit 1 hereto, including the form of Master Forward Confirmation attached as Exhibit C thereto.
This Current Report on Form 8-K is also being filed
to report Exhibit 5.