Spero Therapeutics, Inc.
SPRO- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001701108
No open-market purchases or sales by Spero Therapeutics, Inc. insiders were filed in the last 90 days; 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
2 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 |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Spero Therapeutics, Inc. shares.
No Form 144 notices for Spero Therapeutics, Inc. are on file.