Spero Therapeutics, Inc.
SPRO- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001701108
In the last 90 days, Spero Therapeutics, Inc. insiders filed 0 open-market purchases and 1 sale; 59 institutions reported holding it in 13F filings for Q2 2026, worth $47.5M in total; no superinvestor holds it.
Holders of 5% or more of SPRO
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Spero Therapeutics, Inc., largest stake first. The change is against the holder's previous filing.
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
23 Schedule 13D and 13G filings on Spero Therapeutics, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Aug 14, 20259:48 PM ET | Anson Funds Management LPand 5 others | 13G/A | 2.90%1.62M shares | –Below 5% | Jun 30, 2025 | SEC |
| Mar 28, 20254:30 PM ET | GSK plc | 13D/A | 16.40%9.19M shares | – | Mar 27, 2025 | SEC |
| Nov 14, 2024 | Anson Funds Management LP | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2024 | Anson Funds Management LP | 13GOld format | – | New | – | SEC |
| Feb 14, 2023 | Aquilo Capital Management, LLC | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2023 | Biotechnology Value Fund L P | 13G/AOld format | – | – | – | SEC |
| Jan 20, 2023 | GSK plc | 13D/AOld format | – | – | – | SEC |
| Nov 14, 2022 | GSK plc | 13D/AOld format | – | – | – | SEC |
| Oct 3, 2022 | Aquilo Capital Management, LLC | 13G/AOld format | – | – | – | SEC |
| Jul 8, 20224:57 PM ET | BlackRock Inc. | 13GOld format | – | – | – | SEC |
| Mar 9, 2022 | Aquilo Capital Management, LLC | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2022 | Aquilo Capital Management, LLC | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2022 | Biotechnology Value Fund L P | 13G/AOld format | – | – | – | SEC |
| Feb 3, 20224:29 PM ET | BlackRock Inc. | 13G/AOld format | – | – | – | SEC |
| Jan 25, 2022 | Atlas Venture Fund IX, L.P. | 13G/AOld format | – | – | – | SEC |
| Sep 16, 2021 | GSK plc | 13D/AOld format | – | – | – | SEC |
| Jul 9, 2021 | Pfizer Inc | 13GOld format | – | New | – | SEC |
| Feb 16, 2021 | Atlas Venture Fund X, L.P. | 13D/AOld format | – | – | – | SEC |
| Feb 16, 2021 | Aquilo Capital Management, LLC | 13G/AOld format | – | – | – | SEC |
| Feb 16, 2021 | Biotechnology Value Fund L P | 13G/AOld format | – | – | – | SEC |
| Feb 10, 2021 | GV 2015, L.P. | 13G/AOld format | – | – | – | SEC |
| Feb 2, 20213:13 PM ET | BlackRock Inc. | 13GOld format | – | New | – | SEC |
| Feb 2, 2021 | Atlas Venture Fund IX, L.P. | 13G/AOld format | – | – | – | SEC |
Form 144: proposed insider sales
2 notices from officers, directors and other affiliates planning to sell Spero Therapeutics, Inc. shares, newest first.
| Filed (ET) | Seller | Shares to sell | Market value | Planned sale | Broker | Filing |
|---|---|---|---|---|---|---|
| Feb 5, 20244:50 PM ET | Satyavrat ShuklaOfficer · Director | 45.1K | $65.5K | Feb 5, 202410b5-1 | Morgan Stanley Smith Barney LLC Executive Financial Services | SEC |
| Aug 29, 20234:16 PM ET | Satyavrat ShuklaOfficer | 4.16K | $5.41K | Aug 29, 202310b5-1 | E*TRADE FINANCIAL CORPORATION | SEC |