C3is Inc. SEC filings CISS
C3is Inc. has 320 filings in SEC EDGAR's recent list, going back to Dec 7, 2022. Its latest annual report, Form 20-F, was filed on Apr 22, 2026 for the period ended Dec 31, 2025. The most recent current report (Form 6-K) was filed on Nov 5, 2026. The company's fiscal year ends on December 31.
| Form | Description | Filed | Period |
|---|---|---|---|
| 424B3 | Prospectus | Nov 5, 2026 | — |
| 424B3 | Prospectus | Nov 5, 2026 | — |
| 424B3 | Prospectus | Nov 5, 2026 | — |
| 6-K | Current report (foreign issuer) | Nov 5, 2026 | Nov 5, 2026 |
| EFFECT | Filing | Oct 16, 2026 | — |
| EFFECT | Filing | Oct 16, 2026 | — |
| EFFECT | Filing | Oct 16, 2026 | — |
| POS AM | Filing | Oct 5, 2026 | — |
| POS AM | Filing | Oct 5, 2026 | — |
| POS AM | Filing | Oct 5, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Oct 5, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Oct 5, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Oct 2, 2026 | — |
| 6-K | Current report (foreign issuer) | Sep 29, 2026 | Jun 30, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Sep 3, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Aug 28, 2026 | — |
| 424B3 | Prospectus | Aug 27, 2026 | — |
| 424B3 | Prospectus | Aug 27, 2026 | — |
| 424B3 | Prospectus | Aug 27, 2026 | — |
| 424B3 | Prospectus | Aug 27, 2026 | — |
| 424B3 | Prospectus | Aug 27, 2026 | — |
| 6-K | Current report (foreign issuer) | Aug 27, 2026 | Aug 27, 2026 |
| 424B3 | Prospectus | Aug 19, 2026 | — |
| 424B3 | Prospectus | Aug 19, 2026 | — |
| 424B3 | Prospectus | Aug 19, 2026 | — |
| 424B3 | Prospectus | Aug 19, 2026 | — |
| 424B3 | Prospectus | Aug 19, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Aug 19, 2026 | — |
| 6-K | Current report (foreign issuer) | Aug 19, 2026 | Aug 19, 2026 |
| 6-K | Current report (foreign issuer) | Aug 17, 2026 | Aug 17, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Aug 14, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Aug 14, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Aug 4, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Aug 3, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Aug 3, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Jul 31, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Jul 30, 2026 | — |
| 424B3 | Prospectus | Jul 28, 2026 | — |
| 424B3 | Prospectus | Jul 28, 2026 | — |
| 424B3 | Prospectus | Jul 28, 2026 | — |
| 424B3 | Prospectus | Jul 28, 2026 | — |
| 424B3 | Prospectus | Jul 28, 2026 | — |
| 424B3 | Prospectus | Jul 28, 2026 | — |
| 6-K | Current report (foreign issuer) | Jul 28, 2026 | Jul 28, 2026 |
| 424B4 | Prospectus | Jul 28, 2026 | — |
| EFFECT | Filing | Jul 27, 2026 | — |
| 6-K | Current report (foreign issuer) | Jul 27, 2026 | Jul 27, 2026 |
| F-1/A | Filing | Jul 23, 2026 | — |
| F-1 | Registration statement (foreign issuer) | Jul 22, 2026 | — |
| 6-K | Current report (foreign issuer) | Jul 22, 2026 | Jul 22, 2026 |
| DRS | Filing | Jul 10, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Jun 24, 2026 | — |
| 6-K | Current report (foreign issuer) | Jun 22, 2026 | Jun 22, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | May 18, 2026 | — |
| 424B3 | Prospectus | May 18, 2026 | — |
| 424B3 | Prospectus | May 18, 2026 | — |
| 424B3 | Prospectus | May 18, 2026 | — |
| 424B3 | Prospectus | May 18, 2026 | — |
| 6-K | Current report (foreign issuer) | May 18, 2026 | May 18, 2026 |
| EFFECT | Filing | May 13, 2026 | — |
| EFFECT | Filing | May 13, 2026 | — |
| EFFECT | Filing | May 13, 2026 | — |
| EFFECT | Filing | May 13, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | May 11, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | May 6, 2026 | — |
| POS AM | Filing | May 5, 2026 | — |
| POS AM | Filing | May 5, 2026 | — |
| POS AM | Filing | May 5, 2026 | — |
| POS AM | Filing | May 5, 2026 | — |
| 6-K | Current report (foreign issuer) | Apr 27, 2026 | Apr 27, 2026 |
| 6-K | Current report (foreign issuer) | Apr 23, 2026 | Apr 23, 2026 |
| 20-F | Annual report (foreign issuer) | Apr 22, 2026 | Dec 31, 2025 |
| 3 | Initial insider ownership | Mar 18, 2026 | Mar 18, 2026 |
| 3 | Initial insider ownership | Mar 18, 2026 | Mar 18, 2026 |
| 3 | Initial insider ownership | Mar 18, 2026 | Mar 18, 2026 |
| 3 | Initial insider ownership | Mar 18, 2026 | Mar 18, 2026 |
| 3 | Initial insider ownership | Mar 18, 2026 | Mar 18, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Feb 27, 2026 | — |
| 424B3 | Prospectus | Feb 25, 2026 | — |
| 424B3 | Prospectus | Feb 25, 2026 | — |
| 424B3 | Prospectus | Feb 25, 2026 | — |
| 424B3 | Prospectus | Feb 25, 2026 | — |
| 6-K | Current report (foreign issuer) | Feb 25, 2026 | Feb 25, 2026 |
| 424B5 | Prospectus supplement | Feb 25, 2026 | — |
| 424B3 | Prospectus | Feb 19, 2026 | — |
| 424B3 | Prospectus | Feb 19, 2026 | — |
| 424B3 | Prospectus | Feb 19, 2026 | — |
| 424B3 | Prospectus | Feb 19, 2026 | — |
| 6-K | Current report (foreign issuer) | Feb 19, 2026 | Feb 19, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Feb 11, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Feb 4, 2026 | — |
| 424B3 | Prospectus | Jan 26, 2026 | — |
| 424B3 | Prospectus | Jan 26, 2026 | — |
| 424B3 | Prospectus | Jan 26, 2026 | — |
| 424B3 | Prospectus | Jan 26, 2026 | — |
| 6-K | Current report (foreign issuer) | Jan 26, 2026 | Jan 26, 2026 |
| 424B3 | Prospectus | Jan 22, 2026 | — |
| 424B3 | Prospectus | Jan 22, 2026 | — |
| 424B3 | Prospectus | Jan 22, 2026 | — |
| 424B3 | Prospectus | Jan 22, 2026 | — |
| 6-K | Current report (foreign issuer) | Jan 22, 2026 | Jan 22, 2026 |
| 424B3 | Prospectus | Jan 20, 2026 | — |
| 424B3 | Prospectus | Jan 20, 2026 | — |
| 424B3 | Prospectus | Jan 20, 2026 | — |
| 424B3 | Prospectus | Jan 20, 2026 | — |
| 6-K | Current report (foreign issuer) | Jan 20, 2026 | Jan 20, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jan 14, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jan 13, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Jan 8, 2026 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Dec 30, 2025 | — |
| 424B3 | Prospectus | Dec 19, 2025 | — |
| 424B3 | Prospectus | Dec 19, 2025 | — |
| 424B3 | Prospectus | Dec 19, 2025 | — |
| 424B3 | Prospectus | Dec 19, 2025 | — |
| 6-K | Current report (foreign issuer) | Dec 19, 2025 | Dec 19, 2025 |
| EFFECT | Filing | Dec 18, 2025 | — |
| EFFECT | Filing | Dec 18, 2025 | — |
| EFFECT | Filing | Dec 18, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Dec 18, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Dec 17, 2025 | — |
| POS AM | Filing | Dec 15, 2025 | — |
| POS AM | Filing | Dec 15, 2025 | — |
| POS AM | Filing | Dec 15, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Dec 15, 2025 | — |
| 6-K | Current report (foreign issuer) | Dec 12, 2025 | Dec 12, 2025 |
| 424B4 | Prospectus | Dec 11, 2025 | — |
| EFFECT | Filing | Dec 10, 2025 | — |
| CORRESP | Letter to the SEC | Dec 9, 2025 | — |
| CORRESP | Letter to the SEC | Dec 9, 2025 | — |
| F-1/A | Filing | Dec 5, 2025 | — |
| EFFECT | Filing | Nov 21, 2025 | — |
| 6-K | Current report (foreign issuer) | Nov 18, 2025 | Nov 18, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Nov 14, 2025 | — |
| CORRESP | Letter to the SEC | Nov 3, 2025 | — |
| F-1/A | Filing | Nov 3, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Oct 28, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Oct 10, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Oct 10, 2025 | — |
| 6-K | Current report (foreign issuer) | Oct 9, 2025 | Oct 9, 2025 |
| 424B5 | Prospectus supplement | Oct 9, 2025 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Oct 2, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Oct 1, 2025 | — |
| POS AM | Filing | Oct 1, 2025 | — |
| POS AM | Filing | Oct 1, 2025 | — |
| POS AM | Filing | Oct 1, 2025 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Sep 29, 2025 | — |
| 6-K | Current report (foreign issuer) | Sep 29, 2025 | Jun 30, 2025 |
| SCHEDULE 13G | Ownership over 5% (passive) | Sep 24, 2025 | — |
| UPLOAD | Letter from the SEC | Sep 22, 2025 | — |
| CORRESP | Letter to the SEC | Sep 3, 2025 | — |
| F-1 | Registration statement (foreign issuer) | Sep 3, 2025 | — |
| 424B3 | Prospectus | Sep 2, 2025 | — |
| 424B3 | Prospectus | Sep 2, 2025 | — |
| 424B3 | Prospectus | Sep 2, 2025 | — |
| 6-K | Current report (foreign issuer) | Sep 2, 2025 | Sep 2, 2025 |
| 6-K | Current report (foreign issuer) | Aug 29, 2025 | Aug 29, 2025 |
| UPLOAD | Letter from the SEC | Aug 11, 2025 | — |
| DRSLTR | Filing | Jul 21, 2025 | — |
| DRS | Filing | Jul 21, 2025 | — |
| 6-K | Current report (foreign issuer) | Jun 25, 2025 | Jun 25, 2025 |
| 424B3 | Prospectus | May 16, 2025 | — |
| 424B3 | Prospectus | May 16, 2025 | — |
| 424B3 | Prospectus | May 16, 2025 | — |
| 6-K | Current report (foreign issuer) | May 16, 2025 | May 16, 2025 |
| EFFECT | Filing | May 5, 2025 | — |
| EFFECT | Filing | May 5, 2025 | — |
| EFFECT | Filing | May 5, 2025 | — |
| POS AM | Filing | Apr 30, 2025 | — |
| POS AM | Filing | Apr 30, 2025 | — |
| POS AM | Filing | Apr 30, 2025 | — |
| 20-F | Annual report (foreign issuer) | Apr 28, 2025 | Dec 31, 2024 |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Apr 15, 2025 | — |
| 424B3 | Prospectus | Apr 4, 2025 | — |
| 424B3 | Prospectus | Apr 4, 2025 | — |
| 424B3 | Prospectus | Apr 4, 2025 | — |
| 6-K | Current report (foreign issuer) | Apr 4, 2025 | Apr 4, 2025 |
| 424B3 | Prospectus | Apr 2, 2025 | — |
| 424B3 | Prospectus | Apr 2, 2025 | — |
| 424B3 | Prospectus | Apr 2, 2025 | — |
| 6-K | Current report (foreign issuer) | Apr 2, 2025 | Apr 2, 2025 |
| 424B3 | Prospectus | Mar 12, 2025 | — |
| 424B3 | Prospectus | Mar 12, 2025 | — |
| 424B3 | Prospectus | Mar 12, 2025 | — |
| 6-K | Current report (foreign issuer) | Mar 12, 2025 | Mar 12, 2025 |
| EFFECT | Filing | Mar 6, 2025 | — |
| CORRESP | Letter to the SEC | Mar 4, 2025 | — |
| UPLOAD | Letter from the SEC | Mar 3, 2025 | — |
| F-3 | Shelf registration (foreign issuer) | Feb 21, 2025 | — |
| 6-K | Current report (foreign issuer) | Feb 21, 2025 | Feb 21, 2025 |
| 6-K | Current report (foreign issuer) | Feb 18, 2025 | Feb 18, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 14, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Jan 14, 2025 | — |
| 424B3 | Prospectus | Jan 2, 2025 | — |
| 424B3 | Prospectus | Jan 2, 2025 | — |
| 424B3 | Prospectus | Jan 2, 2025 | — |
| 6-K | Current report (foreign issuer) | Jan 2, 2025 | Jan 2, 2025 |
| EFFECT | Filing | Dec 13, 2024 | — |
| EFFECT | Filing | Dec 13, 2024 | — |
| EFFECT | Filing | Dec 13, 2024 | — |
| POS AM | Filing | Dec 10, 2024 | — |
Showing 200 filings, the most recent 200. 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
- Deep Sea Foreign Transportation of Freight (SIC 4412)
- Listed as
- CISS (Nasdaq)
- Fiscal year ends
- December 31
- Incorporated in
- Marshall Islands
- Headquarters
- Athens, Greece
- SEC filer status
- Non-accelerated filer, Emerging growth company
- SEC CIK
- 1951067
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Source: SEC EDGAR filings. This is company-reported data, not investment advice.