Company: AILIM
Filing Date: 2025-09-16
Form Type: 424B2
Source: 0001104659-25-090464
Chunk: 40

Company: Ameren Illinois Co
Filing Date: 2025-09-16
Form: 424B2
Chunk 40
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 of any date other than the date of the document incorporated by reference. Our business, financial position, results of operations and prospects may have changed since those dates.

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### USE OF PROCEEDS
Unless we state otherwise in any prospectus supplement, we will use the net proceeds we receive from the sale of the offered securities:

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to finance our ongoing construction and maintenance programs;

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to redeem, repurchase, repay or retire outstanding indebtedness and preferred stock; and

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for other general corporate purposes.

The prospectus supplement relating to a particular offering of securities by us will identify the use of proceeds for that offering.

We will not receive any of the proceeds from the sale of any securities by any selling securityholders.

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TABLE OF CONTENTS

### DESCRIPTION OF SENIOR SECURED DEBT SECURITIES

#### General
The senior secured debt securities will be issued in one or more series under, and secured by, our senior secured indenture dated as of June 1, 2006, as amended and supplemented, which we refer to collectively as the “senior secured indenture,” between us (as successor to Illinois Power Company) and The Bank of New York Mellon Trust Company, N.A., as senior secured trustee. The senior secured indenture and the form of supplemental indenture or other instrument establishing the senior secured debt securities of a particular series are exhibits to, or will be subsequently incorporated by reference into, the registration statement of which this prospectus is a part. The senior secured indenture has been qualified under the Trust Indenture Act of 1939. The senior secured debt securities of all series that may be issued under the senior secured indenture are referred to in this prospectus as “senior secured debt securities.” The following summaries of certain provisions of the senior secured indenture do not purport to be complete and are subject to, and qualified in their entirety by, all provisions of the senior secured indenture and the senior secured debt securities.

#### Priority and Security; Release Date
**Until the release date (as defined below), all of the senior secured debt securities outstanding under the senior secured indenture will be secured by one or more series of our first mortgage bonds, which we refer to as the “senior note mortgage bonds,” issued under the mortgage indenture described under “Description of First Mortgage Bonds and Mortgage Indenture” and delivered by us to the senior secured trustee. On the date of