Company: AILIM
Filing Date: 2025-09-16
Form Type: 424B2
Source: 0001104659-25-090464
Chunk: 27

Company: Ameren Illinois Co
Filing Date: 2025-09-16
Form: 424B2
Chunk 27
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 may from time to time vary the offering price and other selling terms. The offering of the bonds by the underwriters is subject to receipt and acceptance and subject to the underwriters’ right to reject any order in whole or in part. The following table sets forth the underwriting discount to be paid to the underwriters by us (expressed as a percentage of the principal amount of the bonds). The underwriting discount is the difference between the offering price and the amount the underwriters pay to purchase the bonds from us.

| ​        | ​ | ​ | Paid by us |   |        |   | ​ |
| Per bond | ​ | ​ | ​          | ​ | 0.875% | ​ | ​ |

The bonds offered by this prospectus supplement will be a further issuance of, will be fungible with, will have the same CUSIP number as, and will be consolidated and form a single series with, our 5.625% First Mortgage Bonds due 2055 issued on March 3, 2025, in the principal amount of $350 million, which class of securities has no established trading market. We do not intend to apply for listing of the bonds on any securities exchange. The underwriters have advised us that they intend to make a market in the bonds after the offering, although they are under no obligation to do so. The underwriters may discontinue any market-making activities at any time without any notice. We can give no assurance as to the liquidity of the trading market for the bonds or that a public trading market for the bonds will develop. Price Stabilization and Short Positions In connection with the offering of the bonds, the underwriters may engage in transactions that stabilize, maintain or otherwise affect the price of the bonds. Specifically, the underwriters may overallot in

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connection with the offering of the bonds, creating a syndicate short position. In addition, the underwriters may bid for, and purchase, the bonds in the open market to cover short positions or to stabilize the price of the bonds. Finally, the underwriters may reclaim selling concessions allowed for distributing the bonds in the offering, if the underwriters repurchase previously distributed bonds in transactions to cover short positions, in stabilization transactions or otherwise. Any of these activities may stabilize or maintain the market price of the bonds above independent market levels. The underwriters are not required to engage in any of these activities, and may end any of them at any time without notice.

The underwriters