Spero TherapeuticsSPRO
13F holders, Q1 2026 (March 31)At the end of Q1 2026, 50 institutions reported holding Spero Therapeutics Inc. (SPRO) in their 13F filings, down 6 from Q4 2025. 5 opened new positions and 12 sold out. The largest holders were GSK plc ($21.5M), Pfizer Inc ($5.5M) and Vanguard Capital Management LLC ($4.2M). 3 famous investors held it, including Jim Simons / Peter Brown (0.0% of Renaissance Technologies's portfolio), Ken Griffin (0.0% of Citadel Advisors's portfolio) and Steve Cohen (0.0% of Point72 Asset Management's portfolio).
- Company
- Spero Therapeutics Inc.
- CUSIP
- 84833T103
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q4 2025 → Q1 2026
| Institutions | Total Value | |
|---|---|---|
| New Positions | 5 | $535K |
| Exits | 12 | $1.3M |
All 13F filers, Q4 2025 → Q1 2026: 1,032,292 shares bought and 1,297,829 shares sold, net −265,537 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 50 holders
| GSK plc | 3.59% | No change | 9,190,606 | $21.5M |
| Pfizer Inc | 2.31% | No change | 2,362,348 | $5.5M |
| Vanguard Capital Management LLC | 0.00% | — | 1,799,880 | $4.2M |
| Renaissance Technologies | 0.00% | Reduce -7.1% | 1,189,235 | $2.8M |
| Alphabet Inc. | 0.05% | No change | 889,979 | $2.1M |
| Two Sigma Investments, LP | 0.00% | Add +137.7% | 885,631 | $2.1M |
| Geode Capital Management, LLC | 0.00% | Reduce -1.8% | 519,922 | $1.2M |
| BlackRock, Inc. | 0.00% | Reduce -0.1% | 433,202 | $1.0M |
| Anson Funds Management LP | 0.13% | Reduce -32.5% | 421,956 | $987K |
| Citadel Advisors | 0.00% | Reduce -5.4% | 376,458 | $881K |
| Susquehanna International Group, LLP | 0.00% | Add +13.4% | 333,115 | $779K |
| Gsa Capital Partners LLP | 0.04% | Add +55.5% | 278,304 | $651K |
| Vanguard Fiduciary Trust Co. | 0.00% | — | 264,115 | $618K |
| State Street Corp. | 0.00% | Add +2.2% | 214,751 | $503K |
| Ionic Capital Management LLC | 0.46% | No change | 195,939 | $458K |
| Squarepoint Ops LLC | 0.00% | Add +62.7% | 194,301 | $455K |
| Marshall Wace, LLP | 0.00% | New | 157,072 | $368K |
| Northern Trust Corp. | 0.00% | No change | 120,984 | $283K |
| Bridgeway Capital Management, LLC | 0.01% | No change | 114,800 | $269K |
| Jane Street Group, LLC | 0.00% | Reduce -32.8% | 106,345 | $249K |
| Shay Capital LLC | 0.02% | Add +16.7% | 70,354 | $165K |
| Point72 Asset Management | 0.00% | Add +36.9% | 59,668 | $140K |
| Invesco Ltd. | 0.00% | Add +83.7% | 45,374 | $106K |
| Quadrature Capital Ltd | 0.00% | Add +6.2% | 40,128 | $94K |
| Capital Asset Advisory Services LLC | 0.00% | No change | 32,548 | $92K |
| OMERS ADMINISTRATION Corp | 0.00% | Reduce -70.0% | 39,400 | $92K |
| Verdad Advisers, LP | 0.09% | New | 33,455 | $78K |
| Simplex Trading, LLC | 0.00% | Reduce -15.1% | 30,304 | $71K |
| Three Seasons Wealth, LLC | 0.03% | No change | 30,000 | $70K |
| Dimensional Fund Advisors LP | 0.00% | No change | 29,768 | $69K |
| Charles Schwab Investment Management Inc. | 0.00% | No change | 28,565 | $67K |
| Vanguard Global Advisers, LLC | 0.00% | — | 25,446 | $60K |
| Schonfeld Strategic Advisors LLC | 0.00% | New | 20,314 | $48K |
| Citigroup Inc. | 0.00% | Add +112458.8% | 19,135 | $45K |
| Assenagon Asset Management S.A. | 0.00% | No change | 18,636 | $44K |
| Occudo Quantitative Strategies LP | 0.00% | New | 16,421 | $41K |
| Intrepid Family Office LLC | 0.03% | Reduce -90.1% | 16,279 | $38K |
| Torrey Growth & Income Advisors | 0.02% | No change | 17,025 | $38K |
| Jones Financial Companies LLLP | 0.00% | Add +18.5% | 7,678 | $18K |
| FNY Investment Advisers, LLC | 0.01% | No change | 5,300 | $12K |
| Morgan Stanley | 0.00% | Add +1354.3% | 4,552 | $11K |
| UBS Group AG | 0.00% | Reduce -97.4% | 3,009 | $7K |
| Osaic Holdings, Inc. | 0.00% | No change | 290 | $678 |
| JPMorgan Chase & Co. | 0.00% | Reduce -95.6% | 236 | $529 |
| Wells Fargo & Company | 0.00% | No change | 200 | $468 |
| US Bancorp \de | 0.00% | No change | 151 | $353 |
| BNP Paribas Financial Markets | 0.00% | No change | 40 | $94 |
| Farther Finance Advisors, LLC | 0.00% | No change | 10 | $25 |
| SBI Securities Co., Ltd. | 0.00% | No change | 9 | $21 |
| Caitong International Asset Management Co., Ltd | 0.00% | New | 3 | $7 |
"% of holder's portfolio" is SPRO's weight in each manager's 13F, not the share of Spero Therapeutics Inc. the manager owns.