Ameren Illinois Co SEC filings AILLO
Ameren Illinois Co has 473 filings in SEC EDGAR's recent list, going back to Feb 28, 1994. Its latest annual report, Form 10-K, was filed on Feb 18, 2026 for the period ended Dec 31, 2025. The latest quarterly report (Form 10-Q) was filed on Aug 3, 2026, covering the quarter ended Jun 30, 2026. The most recent current report (Form 8-K) was filed on Aug 24, 2026 (other events). The company's fiscal year ends on December 31.
| Form | Description | Filed | Period |
|---|---|---|---|
| 424B2 | Prospectus | Aug 18, 2026 | — |
| FWP | Free writing prospectus | Aug 17, 2026 | — |
| 424B3 | Prospectus | Aug 17, 2026 | — |
| S-3ASR | Automatic shelf registration | Aug 4, 2026 | — |
| 424B2 | Prospectus | Sep 16, 2025 | — |
| FWP | Free writing prospectus | Sep 15, 2025 | — |
| 424B3 | Prospectus | Sep 15, 2025 | — |
| 424B2 | Prospectus | Feb 25, 2025 | — |
| FWP | Free writing prospectus | Feb 24, 2025 | — |
| 424B3 | Prospectus | Feb 24, 2025 | — |
| 424B2 | Prospectus | Jun 18, 2024 | — |
| FWP | Free writing prospectus | Jun 17, 2024 | — |
| 424B3 | Prospectus | Jun 17, 2024 | — |
| S-3ASR | Automatic shelf registration | Oct 13, 2023 | — |
| 424B2 | Prospectus | May 24, 2023 | — |
| FWP | Free writing prospectus | May 23, 2023 | — |
| 424B3 | Prospectus | May 23, 2023 | — |
| 424B2 | Prospectus | Nov 9, 2022 | — |
| FWP | Free writing prospectus | Nov 8, 2022 | — |
| 424B3 | Prospectus | Nov 8, 2022 | — |
| 424B2 | Prospectus | Aug 16, 2022 | — |
| FWP | Free writing prospectus | Aug 15, 2022 | — |
| 424B3 | Prospectus | Aug 15, 2022 | — |
| 424B2 | Prospectus | Jun 23, 2021 | — |
| 424B2 | Prospectus | Jun 23, 2021 | — |
| FWP | Free writing prospectus | Jun 22, 2021 | — |
| FWP | Free writing prospectus | Jun 22, 2021 | — |
| 424B3 | Prospectus | Jun 22, 2021 | — |
| 424B3 | Prospectus | Jun 22, 2021 | — |
| 424B2 | Prospectus | Nov 10, 2020 | — |
| FWP | Free writing prospectus | Nov 9, 2020 | — |
| 424B3 | Prospectus | Nov 9, 2020 | — |
| S-3ASR | Automatic shelf registration | Oct 14, 2020 | — |
| 424B2 | Prospectus | Nov 19, 2019 | — |
| FWP | Free writing prospectus | Nov 18, 2019 | — |
| 424B3 | Prospectus | Nov 18, 2019 | — |
| 424B2 | Prospectus | Nov 6, 2018 | — |
| FWP | Free writing prospectus | Nov 5, 2018 | — |
| 424B3 | Prospectus | Nov 5, 2018 | — |
| 424B2 | Prospectus | May 15, 2018 | — |
| FWP | Free writing prospectus | May 14, 2018 | — |
| 424B3 | Prospectus | May 14, 2018 | — |
| S-3ASR | Automatic shelf registration | Dec 15, 2017 | — |
| 424B2 | Prospectus | Nov 17, 2017 | — |
| FWP | Free writing prospectus | Nov 16, 2017 | — |
| 424B3 | Prospectus | Nov 16, 2017 | — |
| 424B2 | Prospectus | Nov 30, 2016 | — |
| FWP | Free writing prospectus | Nov 29, 2016 | — |
| 424B3 | Prospectus | Nov 29, 2016 | — |
| 424B2 | Prospectus | Dec 9, 2015 | — |
| FWP | Free writing prospectus | Dec 7, 2015 | — |
| 424B3 | Prospectus | Dec 7, 2015 | — |
| S-3ASR | Automatic shelf registration | Jun 22, 2015 | — |
| 424B2 | Prospectus | Dec 4, 2014 | — |
| FWP | Free writing prospectus | Dec 3, 2014 | — |
| 424B3 | Prospectus | Dec 3, 2014 | — |
| 424B2 | Prospectus | Jun 25, 2014 | — |
| FWP | Free writing prospectus | Jun 23, 2014 | — |
| 424B3 | Prospectus | Jun 23, 2014 | — |
| 424B2 | Prospectus | Dec 6, 2013 | — |
| FWP | Free writing prospectus | Dec 5, 2013 | — |
| 424B3 | Prospectus | Dec 5, 2013 | — |
| 424B2 | Prospectus | Aug 14, 2012 | — |
| FWP | Free writing prospectus | Aug 13, 2012 | — |
| 424B3 | Prospectus | Aug 13, 2012 | — |
| S-3ASR | Automatic shelf registration | Jun 21, 2012 | — |
| 424B3 | Prospectus | Jul 8, 2010 | — |
| S-4/A | Filing | Jul 6, 2010 | — |
| S-4/A | Filing | Jun 23, 2010 | — |
| S-4 | Registration for a merger or exchange | Apr 15, 2010 | — |
| S-3ASR | Automatic shelf registration | Nov 17, 2008 | — |
| 424B2 | Prospectus | Jun 12, 2006 | — |
| FWP | Free writing prospectus | Jun 9, 2006 | — |
| FWP | Free writing prospectus | Jun 8, 2006 | — |
| 424B3 | Prospectus | Jun 7, 2006 | — |
| 424B5 | Prospectus supplement | Jun 8, 2001 | — |
| S-3 | Shelf registration | Apr 24, 2001 | — |
| 424B5 | Prospectus supplement | Dec 18, 1998 | — |
| 424B3 | Prospectus | Dec 16, 1998 | — |
| S-3DPOS | Filing | Dec 4, 1998 | — |
| 424B2 | Prospectus | Jun 9, 1997 | — |
| 424B2 | Prospectus | Mar 25, 1997 | — |
| 424B2 | Prospectus | Mar 24, 1997 | — |
| 424B5 | Prospectus supplement | Mar 18, 1997 | — |
| S-3/A | Amendment number 1 to form s-3 | Mar 13, 1997 | — |
| S-3 | Shelf registration | Dec 20, 1996 | — |
| 424B3 | Prospectus | Jun 6, 1995 | — |
| 424B5 | Prospectus supplement | Jun 1, 1995 | — |
| 424B3 | Prospectus | Jun 1, 1995 | — |
| S-3 | Shelf registration | Oct 18, 1994 | — |
Showing 90 filings. Main filings leave out insider and ownership forms such as Form 4; choose a type above to see them. Each form opens on SEC.gov. Older filings are on SEC EDGAR.
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Company profile
- Industry
- Electric & Other Services Combined (SIC 4931)
- Listed as
- AILIH (OTC), AILLI (OTC), AILLM (OTC), AILLN (OTC), AILIM (OTC), AILLO (OTC), AILIN (OTC), AILLP (OTC), AILIO (OTC), AILIP (OTC)
- Fiscal year ends
- December 31
- Incorporated in
- IL
- Headquarters
- Collinsville, IL
- SEC CIK
- 18654
- Former names
- CENTRAL ILLINOIS PUBLIC SERVICE CO (until Sep 13, 2010)
Other Electric & Other Services Combined companies
- Duke Energy CORP DUK
- Xcel Energy Inc XEL
- Exelon Corp EXC
- Consolidated Edison Inc ED
- PG&E Corp PCG
- Wec Energy Group, Inc. WEC
- Public Service Enterprise Group Inc PEG
- Ameren Corp AEE
Source: SEC EDGAR filings. This is company-reported data, not investment advice.