Spero Therapeutics, Inc. SEC filings SPRO
Spero Therapeutics, Inc. has 515 filings in SEC EDGAR's recent list, going back to Mar 21, 2017. Its latest annual report, Form ARS, was filed on Apr 27, 2026 for the period ended Dec 31, 2025. The latest quarterly report (Form 10-Q) was filed on Aug 12, 2026, covering the quarter ended Jun 30, 2026. The most recent current report (Form 8-K) was filed on Oct 27, 2026 (officer or director change). The company's fiscal year ends on December 31.
| Form | Description | Filed | Period |
|---|---|---|---|
| S-8 | Employee stock plan registration | Oct 28, 2026 | — |
| 8-K |
Current report
Officer or director change
|
Oct 27, 2026 | Oct 26, 2026 |
| EFFECT | Filing | Sep 10, 2026 | — |
| 8-K |
Current report
Material agreement, Other events
|
Aug 28, 2026 | Aug 28, 2026 |
| S-3 | Shelf registration | Aug 28, 2026 | — |
| 8-K |
Current report
Results of operations
|
Aug 12, 2026 | Aug 12, 2026 |
| 10-Q | Quarterly report | Aug 12, 2026 | Jun 30, 2026 |
| 8-K |
Current report
Material agreement, New debt, Regulation FD disclosure, Other events
|
Jul 14, 2026 | Jul 8, 2026 |
| 8-K |
Current report
Officer or director change, Bylaw or fiscal year change, Shareholder vote results
|
Jun 25, 2026 | Jun 23, 2026 |
| S-8 | Employee stock plan registration | Jun 23, 2026 | — |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Jun 22, 2026 | Jun 17, 2026 |
| 10-Q | Quarterly report | May 13, 2026 | Mar 31, 2026 |
| 8-K |
Current report
Results of operations
|
May 13, 2026 | May 13, 2026 |
| ARS | Annual report to shareholders | Apr 27, 2026 | Dec 31, 2025 |
| DEFA14A | Additional proxy material | Apr 27, 2026 | — |
| DEF 14A | Proxy statement | Apr 27, 2026 | Jun 23, 2026 |
| PRE 14A | Preliminary proxy statement | Apr 13, 2026 | Jun 23, 2026 |
| 8-K |
Current report
Results of operations
|
Mar 26, 2026 | Mar 26, 2026 |
| 10-K | Annual report | Mar 26, 2026 | Dec 31, 2025 |
| 8-K |
Current report
Officer or director change, Other events
|
Jan 30, 2026 | Jan 30, 2026 |
| 8-K |
Current report
Other events
|
Dec 19, 2025 | Dec 19, 2025 |
| 8-K |
Current report
Results of operations, Regulation FD disclosure
|
Nov 13, 2025 | Nov 13, 2025 |
| 10-Q | Quarterly report | Nov 13, 2025 | Sep 30, 2025 |
| S-8 | Employee stock plan registration | Aug 12, 2025 | — |
| 10-Q | Quarterly report | Aug 12, 2025 | Jun 30, 2025 |
| 8-K |
Current report
Results of operations, Regulation FD disclosure
|
Aug 12, 2025 | Aug 12, 2025 |
| 8-K |
Current report
Officer or director change, Shareholder vote results
|
Jun 18, 2025 | Jun 12, 2025 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
May 28, 2025 | May 28, 2025 |
| 8-K |
Current report
Results of operations
|
May 13, 2025 | May 13, 2025 |
| 10-Q | Quarterly report | May 13, 2025 | Mar 31, 2025 |
| ARS | Annual report to shareholders | Apr 28, 2025 | Dec 31, 2024 |
| DEFA14A | Additional proxy material | Apr 28, 2025 | — |
| DEF 14A | Proxy statement | Apr 28, 2025 | Jun 12, 2025 |
| 8-K |
Current report
Officer or director change
|
Apr 28, 2025 | Apr 22, 2025 |
| 8-K |
Current report
Results of operations
|
Mar 27, 2025 | Mar 27, 2025 |
| 10-K | Annual report | Mar 27, 2025 | Dec 31, 2024 |
| 8-K |
Current report
Listing notice
|
Feb 28, 2025 | Feb 25, 2025 |
| 8-K |
Current report
Results of operations, Officer or director change, Regulation FD disclosure, Other events
|
Jan 10, 2025 | Jan 7, 2025 |
| 8-K |
Current report
Results of operations
|
Nov 14, 2024 | Nov 14, 2024 |
| 10-Q | Quarterly report | Nov 14, 2024 | Sep 30, 2024 |
| 8-K |
Current report
Results of operations, Exit or restructuring costs, Regulation FD disclosure, Other events
|
Oct 29, 2024 | Oct 29, 2024 |
| 8-K |
Current report
Regulation FD disclosure
|
Sep 10, 2024 | Sep 9, 2024 |
| S-8 | Employee stock plan registration | Aug 5, 2024 | — |
| 10-Q | Quarterly report | Aug 5, 2024 | Jun 30, 2024 |
| 8-K |
Current report
Results of operations, Regulation FD disclosure
|
Aug 5, 2024 | Aug 5, 2024 |
| 8-K |
Current report
Officer or director change, Shareholder vote results
|
Jun 3, 2024 | May 29, 2024 |
| 8-K |
Current report
Results of operations
|
May 15, 2024 | May 15, 2024 |
| 10-Q | Quarterly report | May 15, 2024 | Mar 31, 2024 |
| ARS | Annual report to shareholders | Apr 16, 2024 | Dec 31, 2023 |
| DEFA14A | Additional proxy material | Apr 16, 2024 | — |
| DEF 14A | Proxy statement | Apr 16, 2024 | May 29, 2024 |
| 8-K |
Current report
Other events
|
Mar 29, 2024 | Mar 29, 2024 |
| EFFECT | Filing | Mar 22, 2024 | — |
| CORRESP | Letter to the SEC | Mar 20, 2024 | — |
| UPLOAD | Letter from the SEC | Mar 20, 2024 | — |
| S-3 | Shelf registration | Mar 15, 2024 | — |
| S-8 | Employee stock plan registration | Mar 15, 2024 | — |
| 10-K | Annual report | Mar 13, 2024 | Dec 31, 2023 |
| 8-K |
Current report
Results of operations
|
Mar 13, 2024 | Mar 13, 2024 |
| 8-K |
Current report
Officer or director change
|
Feb 9, 2024 | Feb 5, 2024 |
| 8-K |
Current report
Regulation FD disclosure
|
Jan 8, 2024 | Jan 8, 2024 |
| 8-K |
Current report
Results of operations, Regulation FD disclosure, Other events
|
Jan 5, 2024 | Jan 5, 2024 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Jan 2, 2024 | Jan 2, 2024 |
| S-8 | Employee stock plan registration | Nov 13, 2023 | — |
| S-8 | Employee stock plan registration | Nov 13, 2023 | — |
| 8-K |
Current report
Results of operations
|
Nov 13, 2023 | Nov 13, 2023 |
| 10-Q | Quarterly report | Nov 13, 2023 | Sep 30, 2023 |
| 8-K |
Current report
Officer or director change, Other events
|
Nov 1, 2023 | Oct 30, 2023 |
| 8-K/A |
Amended current report
Bylaw or fiscal year change, Shareholder vote results
|
Oct 16, 2023 | Oct 5, 2023 |
| 8-K |
Current report
Officer or director change, Bylaw or fiscal year change, Shareholder vote results
|
Oct 10, 2023 | Oct 5, 2023 |
| ARS | Annual report to shareholders | Sep 1, 2023 | Dec 31, 2022 |
| DEF 14A | Proxy statement | Sep 1, 2023 | Oct 5, 2023 |
| PRE 14A | Preliminary proxy statement | Aug 22, 2023 | Oct 5, 2023 |
| S-8 | Employee stock plan registration | Aug 10, 2023 | — |
| 8-K |
Current report
Results of operations
|
Aug 10, 2023 | Aug 10, 2023 |
| 10-Q | Quarterly report | Aug 10, 2023 | Jun 30, 2023 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Jul 31, 2023 | Jul 31, 2023 |
| 8-K |
Current report
Officer or director change, Other events
|
Jun 14, 2023 | Jun 12, 2023 |
| 8-K |
Current report
Results of operations
|
May 11, 2023 | May 11, 2023 |
| 10-Q | Quarterly report | May 11, 2023 | Mar 31, 2023 |
| S-8 | Employee stock plan registration | Mar 30, 2023 | — |
| 8-K |
Current report
Results of operations
|
Mar 30, 2023 | Mar 30, 2023 |
| 10-K | Annual report | Mar 30, 2023 | Dec 31, 2022 |
| 8-K |
Current report
Officer or director change
|
Feb 1, 2023 | Jan 30, 2023 |
| CT ORDER | Filing | Jan 19, 2023 | — |
| 8-K |
Current report
Results of operations, Regulation FD disclosure, Other events
|
Jan 9, 2023 | Jan 9, 2023 |
| D | Filing | Nov 15, 2022 | — |
| S-8 | Employee stock plan registration | Nov 14, 2022 | — |
| 8-K |
Current report
Results of operations
|
Nov 14, 2022 | Nov 14, 2022 |
| 10-Q | Quarterly report | Nov 14, 2022 | Sep 30, 2022 |
| 8-K |
Current report
Other events
|
Nov 8, 2022 | Nov 8, 2022 |
| 8-K |
Current report
Material agreement, Unregistered share sale, Other events
|
Sep 22, 2022 | Sep 21, 2022 |
| 8-K |
Current report
Officer or director change, Shareholder vote results
|
Sep 19, 2022 | Sep 15, 2022 |
| 8-K |
Current report
Other events
|
Sep 6, 2022 | Sep 6, 2022 |
| 8-K |
Current report
Results of operations
|
Aug 10, 2022 | Aug 10, 2022 |
| 10-Q | Quarterly report | Aug 10, 2022 | Jun 30, 2022 |
| DEFA14A | Additional proxy material | Aug 5, 2022 | — |
| DEF 14A | Proxy statement | Aug 5, 2022 | Sep 15, 2022 |
| 8-K |
Current report
Officer or director change
|
Jul 1, 2022 | Jul 1, 2022 |
| 8-K |
Current report
Other events
|
Jun 27, 2022 | Jun 27, 2022 |
| 8-K |
Current report
Agreement ended
|
Jun 7, 2022 | Jun 7, 2022 |
| 8-K |
Current report
Results of operations
|
May 16, 2022 | May 16, 2022 |
| 10-Q | Quarterly report | May 16, 2022 | Mar 31, 2022 |
| 8-K |
Current report
Exit or restructuring costs, Officer or director change, Other events
|
May 3, 2022 | May 3, 2022 |
| 8-K |
Current report
Other events
|
Apr 7, 2022 | Apr 6, 2022 |
| 8-K |
Current report
Results of operations
|
Mar 31, 2022 | Mar 31, 2022 |
| 10-K | Annual report | Mar 31, 2022 | Dec 31, 2021 |
| 8-K |
Current report
Other events
|
Feb 16, 2022 | Feb 16, 2022 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Jan 25, 2022 | Jan 25, 2022 |
| 8-K |
Current report
Other events
|
Jan 19, 2022 | Jan 19, 2022 |
| 8-K |
Current report
Other events
|
Jan 4, 2022 | Jan 3, 2022 |
| CT ORDER | Filing | Dec 16, 2021 | — |
| 8-K |
Current report
Results of operations
|
Nov 10, 2021 | Nov 10, 2021 |
| 10-Q | Quarterly report | Nov 10, 2021 | Sep 30, 2021 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Oct 28, 2021 | Oct 27, 2021 |
| 8-K |
Current report
Officer or director change
|
Oct 12, 2021 | Oct 11, 2021 |
| 8-K |
Current report
Material agreement, New debt
|
Sep 30, 2021 | Sep 29, 2021 |
| S-8 | Employee stock plan registration | Sep 20, 2021 | — |
| 8-K |
Current report
Officer or director change
|
Aug 30, 2021 | Aug 26, 2021 |
| 8-K |
Current report
Officer or director change, Bylaw or fiscal year change, Shareholder vote results
|
Aug 18, 2021 | Aug 17, 2021 |
| 8-K |
Current report
Results of operations
|
Aug 5, 2021 | Aug 5, 2021 |
| 10-Q | Quarterly report | Aug 5, 2021 | Jun 30, 2021 |
| D | Filing | Jul 14, 2021 | — |
| DEF 14A | Proxy statement | Jul 6, 2021 | Aug 17, 2021 |
| 8-K |
Current report
Material agreement, Unregistered share sale
|
Jul 1, 2021 | Jun 30, 2021 |
| PRE 14A | Preliminary proxy statement | Jun 25, 2021 | Aug 17, 2021 |
| 8-K |
Current report
Results of operations
|
May 6, 2021 | May 6, 2021 |
| 10-Q | Quarterly report | May 6, 2021 | Mar 31, 2021 |
| EFFECT | Filing | Mar 29, 2021 | — |
| CORRESP | Letter to the SEC | Mar 24, 2021 | — |
| 10-K/A | Amended annual report | Mar 23, 2021 | Dec 31, 2020 |
| UPLOAD | Letter from the SEC | Mar 17, 2021 | — |
| S-8 | Employee stock plan registration | Mar 11, 2021 | — |
| S-3 | Shelf registration | Mar 11, 2021 | — |
| 8-K |
Current report
Results of operations
|
Mar 11, 2021 | Mar 11, 2021 |
| 10-K | Annual report | Mar 11, 2021 | Dec 31, 2020 |
| 8-K |
Current report
Other events
|
Feb 5, 2021 | Feb 5, 2021 |
| 8-K |
Current report
Material agreement
|
Jan 19, 2021 | Jan 15, 2021 |
| 8-K |
Current report
Officer or director change, Other events
|
Dec 17, 2020 | Dec 9, 2020 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Dec 3, 2020 | Dec 3, 2020 |
| 424B5 | Prospectus supplement | Nov 13, 2020 | — |
| 8-K |
Current report
Results of operations
|
Nov 5, 2020 | Nov 5, 2020 |
| 10-Q | Quarterly report | Nov 5, 2020 | Sep 30, 2020 |
| 8-K |
Current report
Shareholder vote results
|
Oct 28, 2020 | Oct 27, 2020 |
| DEF 14A | Proxy statement | Sep 30, 2020 | Oct 27, 2020 |
| 8-K |
Current report
Regulation FD disclosure
|
Sep 16, 2020 | Sep 16, 2020 |
| 8-K |
Current report
Material agreement, Bylaw or fiscal year change, Other events
|
Sep 14, 2020 | Sep 10, 2020 |
| 424B5 | Prospectus supplement | Sep 14, 2020 | — |
| 424B5 | Prospectus supplement | Sep 9, 2020 | — |
| 8-K |
Current report
Other events
|
Sep 9, 2020 | Sep 9, 2020 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Sep 8, 2020 | Sep 8, 2020 |
| S-8 | Employee stock plan registration | Aug 6, 2020 | — |
| 8-K |
Current report
Results of operations
|
Aug 6, 2020 | Aug 6, 2020 |
| 10-Q | Quarterly report | Aug 6, 2020 | Jun 30, 2020 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Jun 4, 2020 | Jun 4, 2020 |
| 8-K/A |
Amended current report
Officer or director change
|
May 11, 2020 | Apr 16, 2020 |
| 8-K |
Current report
Results of operations
|
May 8, 2020 | May 8, 2020 |
| 10-Q | Quarterly report | May 8, 2020 | Mar 31, 2020 |
| 8-K |
Current report
Officer or director change
|
Apr 16, 2020 | Apr 16, 2020 |
| S-8 | Employee stock plan registration | Mar 19, 2020 | — |
| 8-K |
Current report
Results of operations
|
Mar 16, 2020 | Mar 16, 2020 |
| 10-K | Annual report | Mar 16, 2020 | Dec 31, 2019 |
| 8-K |
Current report
Change to shareholder rights, Bylaw or fiscal year change, Other events
|
Feb 28, 2020 | Feb 28, 2020 |
| 8-K |
Current report
Results of operations, Other events
|
Feb 11, 2020 | Feb 11, 2020 |
| 424B5 | Prospectus supplement | Feb 11, 2020 | — |
| 8-K |
Current report
Material agreement, Unregistered share sale, Other events
|
Jan 30, 2020 | Jan 30, 2020 |
| 8-K |
Current report
Material agreement, New debt
|
Dec 19, 2019 | Dec 16, 2019 |
| 8-K |
Current report
Regulation FD disclosure
|
Dec 5, 2019 | Dec 5, 2019 |
| 8-K |
Current report
Results of operations
|
Nov 4, 2019 | Nov 4, 2019 |
| 10-Q | Quarterly report | Nov 4, 2019 | Sep 30, 2019 |
| 8-K |
Current report
Regulation FD disclosure
|
Oct 3, 2019 | Oct 3, 2019 |
| 8-K |
Current report
Officer or director change
|
Sep 6, 2019 | Sep 4, 2019 |
| 8-K |
Current report
Results of operations
|
Aug 8, 2019 | Aug 8, 2019 |
| 10-Q | Quarterly report | Aug 8, 2019 | Jun 30, 2019 |
| 424B5 | Prospectus supplement | Jun 14, 2019 | — |
| 8-K |
Current report
Material agreement
|
Jun 13, 2019 | Jun 12, 2019 |
| 8-K |
Current report
Shareholder vote results
|
Jun 6, 2019 | Jun 5, 2019 |
| 8-K |
Current report
Results of operations
|
May 9, 2019 | May 9, 2019 |
| 10-Q | Quarterly report | May 9, 2019 | Mar 31, 2019 |
| DEF 14A | Proxy statement | Apr 26, 2019 | Jun 5, 2019 |
| 8-K |
Current report
Officer or director change
|
Apr 18, 2019 | Apr 18, 2019 |
| CT ORDER | Filing | Apr 1, 2019 | — |
| 8-K/A |
Amended current report
Officer or director change
|
Mar 29, 2019 | Mar 19, 2019 |
| 8-K |
Current report
Officer or director change
|
Mar 19, 2019 | Mar 19, 2019 |
| S-8 | Employee stock plan registration | Mar 14, 2019 | — |
| S-8 | Employee stock plan registration | Mar 14, 2019 | — |
| 8-K |
Current report
Results of operations
|
Mar 14, 2019 | Mar 14, 2019 |
| 10-K | Annual report | Mar 14, 2019 | Dec 31, 2018 |
| 8-K |
Current report
Material agreement, Other events
|
Jan 7, 2019 | Jan 4, 2019 |
| EFFECT | Filing | Dec 11, 2018 | — |
| CT ORDER | Filing | Dec 11, 2018 | — |
| CORRESP | Letter to the SEC | Dec 7, 2018 | — |
| S-3 | Shelf registration | Dec 3, 2018 | — |
| 8-K |
Current report
Material agreement, Unregistered share sale, Change to shareholder rights, Bylaw or fiscal year change
|
Nov 16, 2018 | Nov 15, 2018 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Nov 13, 2018 | Nov 13, 2018 |
| 8-K |
Current report
Results of operations
|
Nov 8, 2018 | Nov 8, 2018 |
| 10-Q | Quarterly report | Nov 8, 2018 | Sep 30, 2018 |
| 8-K |
Current report
Regulation FD disclosure
|
Sep 27, 2018 | Sep 27, 2018 |
| 8-K |
Current report
Officer or director change
|
Aug 14, 2018 | Aug 14, 2018 |
| 8-K |
Current report
Results of operations
|
Aug 9, 2018 | Aug 9, 2018 |
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
- Pharmaceutical Preparations (SIC 2834)
- Listed as
- SPRO (Nasdaq)
- Fiscal year ends
- December 31
- Incorporated in
- DE
- Headquarters
- Cambridge, MA
- SEC filer status
- Non-accelerated filer, Smaller reporting company
- SEC CIK
- 1701108
- Former names
- Spero Therapeutics, LLC (until Mar 21, 2017)
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- ELI LILLY & Co LLY
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Source: SEC EDGAR filings. This is company-reported data, not investment advice.