Company: AILIM
Filing Date: 2025-09-16
Form Type: 424B2
Source: 0001104659-25-090464
Chunk: 38

Company: Ameren Illinois Co
Filing Date: 2025-09-16
Form: 424B2
Chunk 38
---
4, as amended (the “Exchange Act”), which are incorporated by reference into this prospectus. Before making an investment decision, you should carefully consider these risks as well as other information we include or incorporate by reference in this prospectus. There may be additional risks and uncertainties (either currently unknown or not currently believed to be material) that could adversely affect the results of our operations, financial position and liquidity. New risks may emerge at any time and we cannot predict such risks or estimate the extent to which they may affect our financial performance. The prospectus supplement applicable to each type or series of securities we offer may contain a discussion of additional risks applicable to an investment in us and the particular type of securities we are offering under that prospectus supplement. Each of the risks described could result in a decrease in the value of the particular securities and your investment therein.

<div align='center'>2</div>

TABLE OF CONTENTS

### WHERE YOU CAN FIND MORE INFORMATION
We have filed a registration statement on Form S-3 with the SEC under the Securities Act of 1933, as amended (the “Securities Act”). This prospectus is part of the registration statement, but the registration statement also contains or incorporates by reference additional information and exhibits. We are subject to the informational requirements of the Exchange Act and, therefore, we file annual, quarterly and current reports, information statements and other information with the SEC. The SEC maintains a website at www.sec.gov that contains reports, proxy and information statements and other information regarding companies, such as us, that file documents with the SEC electronically. The documents can be found by searching the EDGAR archives of the SEC electronically.

The SEC allows us to “incorporate by reference” the information that we file with the SEC which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus and you should read it with the same care. Later information that we file with the SEC will automatically update and supersede this information and will be deemed to be incorporated by reference into this prospectus (other than any documents, or portions of documents, not deemed to be filed). We incorporate by reference the following documents previously filed with the SEC:

•

our Annual Report on Form 10-K for the year ended December 31, 2022;

•

our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2023and June 30, 2023; and

•

our Current Reports