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.
13F holders, Q1 2026
Institutional positions in Spero Therapeutics, Inc. as of Mar 31, 2026. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works
- Institutional holders
- 50
- −5 vs. Q4 2025
- Shares held
- 20.6M
- +1.61M (+8.4%) vs. Q4 2025
- Total value
- $48.3M
- +$3.94M (+8.9%) vs. Q4 2025
- New holders
- 8
- 12 more added
- Sold out
- 13
- 11 more reduced
1 institution that held it in Q4 2025 haven't filed for Q1 2026 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.
Compare with Q4 2025: new holders, sold out and not filed yet
Holders and value by quarter
Institutions reporting SPRO on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.
| Quarter | Holders | Value |
|---|---|---|
| Q2 2026 | 59 | $47.5M |
| Q1 2026 | 50 | $49.3M |
| Q4 2025 | 56 | $49.2M |
| Q3 2025 | 47 | $21.3M |
| Q2 2025 | 44 | $32.1M |
| Q1 2025 | 38 | $10.9M |
| Q4 2024 | 50 | $16.5M |
| Q3 2024 | 46 | $16.5M |
| Q2 2024 | 48 | $18.0M |
| Q1 2024 | 54 | $23.7M |
| Q4 2023 | 50 | $143.1M |
| Q3 2023 | 54 | $17.2M |
| Q2 2023 | 56 | $20.8M |
| Q1 2023 | 48 | $25.5M |
| Q4 2022 | 60 | $24.6M |
| Q3 2022 | 69 | $39.7M |
| Q2 2022 | 79 | $15.5M |
| Q1 2022 | 100 | $179.6M |
| Q4 2021 | 84 | $318.3M |
| Q3 2021 | 87 | $338.2M |
| Q2 2021 | 88 | $244.1M |
| Q1 2021 | 94 | $273.1M |
Institutions, Q1 2026
Shares, value and share of portfolio for each institution holding Spero Therapeutics, Inc.; share changes are against Q4 2025.
| Institution | Shares | Value | % of portfolio | Change in shares | Action |
|---|---|---|---|---|---|
| GSK plc | 9,190,606 | $21.5M | 3.59% | 00.0% | Unchanged |
| Pfizer Inc | 2,362,348 | $5.50M | 2.31% | 00.0% | Unchanged |
| Vanguard Capital Management LLC | 1,799,880 | $4.21M | 0.00% | +1,799,880 | New |
| Renaissance Technologies LLC | 1,189,235 | $2.78M | 0.00% | −90,287−7.1% | Reduced |
| Alphabet Inc. | 889,979 | $2.08M | 0.05% | 00.0% | Unchanged |
| Two Sigma Investments, LP | 885,631 | $2.07M | 0.00% | +513,061+137.7% | Added |
| Geode Capital Management, LLC | 519,922 | $1.22M | 0.00% | −9,273−1.8% | Reduced |
| BlackRock, Inc. | 433,202 | $1.01M | 0.00% | −414−0.1% | Reduced |
| Anson Funds Management LP | 421,956 | $987.4K | 0.13% | −203,106−32.5% | Reduced |
| Citadel Advisors LLC | 376,458 | $880.9K | 0.00% | −21,406−5.4% | Reduced |
| Susquehanna International Group, LLP | 333,115 | $779.5K | 0.00% | +39,415+13.4% | Added |
| Gsa Capital Partners LLP | 278,304 | $651.0K | 0.04% | +99,374+55.5% | Added |
| Vanguard Fiduciary Trust Co | 264,115 | $618.0K | 0.00% | +264,115 | New |
| State Street Corp | 214,751 | $502.5K | 0.00% | +4,600+2.2% | Added |
| Ionic Capital Management LLC | 195,939 | $458.5K | 0.38% | 00.0% | Unchanged |
| Squarepoint Ops LLC | 194,301 | $454.7K | 0.00% | +74,867+62.7% | Added |
| Marshall Wace, LLP | 157,072 | $367.5K | 0.00% | +157,072 | New |
| Northern Trust Corp | 120,984 | $283.1K | 0.00% | 00.0% | Unchanged |
| Bridgeway Capital Management, LLC | 114,800 | $268.6K | 0.01% | 00.0% | Unchanged |
| Jane Street Group, LLC | 106,345 | $248.8K | 0.00% | −51,999−32.8% | Reduced |
| Shay Capital LLC | 70,354 | $164.6K | 0.02% | +10,065+16.7% | Added |
| Point72 Asset Management, L.P. | 59,668 | $139.6K | 0.00% | +16,089+36.9% | Added |
| Invesco Ltd. | 45,374 | $106.2K | 0.00% | +20,669+83.7% | Added |
| Quadrature Capital Ltd | 40,128 | $93.9K | 0.00% | +2,329+6.2% | Added |
| Capital Asset Advisory Services LLC | 32,548 | $92.4K | 0.00% | 00.0% | Unchanged |
| Omers Administration Corp | 39,400 | $92.2K | 0.00% | −91,727−70.0% | Reduced |
| Verdad Advisers, LP | 33,455 | $78.3K | 0.09% | +33,455 | New |
| Simplex Trading, LLC | 30,304 | $70.9K | 0.00% | −5,382−15.1% | Reduced |
| Three Seasons Wealth, LLC | 30,000 | $70.2K | 0.03% | 00.0% | Unchanged |
| Dimensional Fund Advisors LP | 29,768 | $69.2K | 0.00% | 00.0% | Unchanged |
| Charles Schwab Investment Management Inc | 28,565 | $66.8K | 0.00% | 00.0% | Unchanged |
| Vanguard Global Advisers, LLC | 25,446 | $59.5K | 0.00% | +25,446 | New |
| Schonfeld Strategic Advisors LLC | 20,314 | $47.5K | 0.00% | +20,314 | New |
| Citigroup Inc | 19,135 | $44.8K | 0.00% | +19,118+112,458.8% | Added |
| Assenagon Asset Management S.A. | 18,636 | $43.6K | 0.00% | 00.0% | Unchanged |
| Occudo Quantitative Strategies LP | 16,421 | $41.2K | 0.00% | +16,421 | New |
| Intrepid Family Office LLC | 16,279 | $38.1K | 0.03% | −148,721−90.1% | Reduced |
| Torrey Growth & Income Advisors | 17,025 | $37.6K | 0.02% | 00.0% | Unchanged |
| Jones Financial Companies LLLP | 7,678 | $17.9K | 0.00% | +1,201+18.5% | Added |
| FNY Investment Advisers, LLC | 5,300 | $12.0K | 0.01% | 00.0% | Unchanged |
| Morgan Stanley | 4,552 | $10.7K | 0.00% | +4,239+1,354.3% | Added |
| UBS Group AG | 3,009 | $7.04K | 0.00% | −113,438−97.4% | Reduced |
| Advisor Group Holdings, Inc. | 290 | $678 | 0.00% | 00.0% | Unchanged |
| JPMorgan Chase & Co | 236 | $529 | 0.00% | −5,137−95.6% | Reduced |
| Wells Fargo & Company | 200 | $468 | 0.00% | 00.0% | Unchanged |
| US Bancorp | 151 | $353 | 0.00% | 00.0% | Unchanged |
| BNP Paribas Arbitrage, SA | 40 | $94 | 0.00% | 00.0% | Unchanged |
| Farther Finance Advisors, LLC | 10 | $25 | 0.00% | 00.0% | Unchanged |
| SBI Securities Co., Ltd. | 9 | $21 | 0.00% | 00.0% | Unchanged |
| Caitong International Asset Management Co., Ltd | 3 | $7 | 0.00% | +3 | New |
| EAM Investors, LLC | 0 | $0 | 0.00% | −218,084−100.0% | Sold out |
| Two Sigma Advisers, LP | 0 | $0 | 0.00% | −216,600−100.0% | Sold out |
| SEI Investments Co | 0 | $0 | 0.00% | −132,010−100.0% | Sold out |
| ADAR1 Capital Management, LLC | 0 | $0 | 0.00% | −113,839−100.0% | Sold out |
| Axxcess Wealth Management, LLC | 0 | $0 | 0.00% | −32,548−100.0% | Sold out |
| Millennium Management LLC | 0 | $0 | 0.00% | −24,107−100.0% | Sold out |
| XTX Topco Ltd | 0 | $0 | 0.00% | −15,175−100.0% | Sold out |
| Texas Yale Capital Corp. | 0 | $0 | 0.00% | −10,000−100.0% | Sold out |
| Tower Research Capital LLC (TRC) | 0 | $0 | 0.00% | −7,215−100.0% | Sold out |
| Cullen/Frost Bankers, Inc. | 0 | $0 | 0.00% | −3,000−100.0% | Sold out |
| Bank of America Corp | 0 | $0 | 0.00% | −744−100.0% | Sold out |
| Rockefeller Capital Management L.P. | 0 | $0 | 0.00% | −200−100.0% | Sold out |
| SageView Advisory Group, LLC | 0 | $0 | 0.00% | −17−100.0% | Sold out |
| Vanguard Group Inc | – | – | – | – | Not filed |