Spero Therapeutics, Inc. - SPRO
Detailed investor-level table based on 13F positions.
Methodology:
Market value and % of portfolio use SEC reported VALUE ($000).
For PUT/CALL positions this reflects reported underlying exposure, not premium cash paid/received.
Details.
Rows: 0
| Investor | History | Status | Shares held | Market value ($000) | % of portfolio | Previous % | Rank | Change in shares | % change in shares | Source | Date reported |
|---|---|---|---|---|---|---|---|---|---|---|---|
| GSK plc | History | No change | 9,190,606 | 21,506 | 3.59% | 2.68% | 1 | 0 | 0.0% | Q1 2026 | May 14, 2026 |
| PFIZER INC | History | No change | 2,362,348 | 5,504 | 2.31% | 2.33% | 2 | 0 | 0.0% | Q1 2026 | May 12, 2026 |
| VANGUARD GROUP INC | History | No change | 2,083,462 | 4,854 | 0.0% | 0.0% | 3 | 0 | 0.0% | Q4 2025 | Jan 29, 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC | History | New | 1,799,880 | 4,211 | 0.0% | — | 4 | +1,799,880 | New | Q1 2026 | May 15, 2026 |
| RENAISSANCE TECHNOLOGIES LLC | History | Reduced | 1,189,235 | 2,782 | 0.0% | 0.0% | 5 | -90,287 | -7.06% | Q1 2026 | May 14, 2026 |
| Alphabet Inc. | History | No change | 889,979 | 2,082 | 0.05% | 0.08% | 6 | 0 | 0.0% | Q1 2026 | May 07, 2026 |
| TWO SIGMA INVESTMENTS, LP | History | Added to | 885,631 | 2,072 | 0.0% | 0.0% | 7 | +513,061 | 137.71% | Q1 2026 | May 15, 2026 |
| GEODE CAPITAL MANAGEMENT, LLC | History | Reduced | 519,922 | 1,217 | 0.0% | 0.0% | 8 | -9,273 | -1.75% | Q1 2026 | May 15, 2026 |
| BlackRock, Inc. | History | Reduced | 433,202 | 1,013 | 0.0% | 0.0% | 9 | -414 | -0.1% | Q1 2026 | May 13, 2026 |
| CITADEL ADVISORS LLC | History | Reduced | 425,658 | 996 | 0.0% | 0.0% | 10 | -45,306 | -9.62% | Q1 2026 | May 15, 2026 |
| Anson Funds Management LP | History | Reduced | 421,956 | 987 | 0.09% | 0.14% | 11 | -203,106 | -32.49% | Q1 2026 | May 14, 2026 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | History | Added to | 381,615 | 892 | 0.0% | 0.0% | 12 | +87,915 | 29.93% | Q1 2026 | May 15, 2026 |
| GSA CAPITAL PARTNERS LLP | History | Added to | 278,304 | 651 | 0.04% | 0.04% | 13 | +99,374 | 55.54% | Q1 2026 | May 08, 2026 |
| VANGUARD FIDUCIARY TRUST CO | History | New | 264,115 | 618 | 0.0% | — | 14 | +264,115 | New | Q1 2026 | May 08, 2026 |
| TWO SIGMA ADVISERS, LP | History | No change | 216,600 | 504 | 0.0% | 0.0% | 15 | 0 | 0.0% | Q4 2025 | Feb 17, 2026 |
| STATE STREET CORP | History | Added to | 214,751 | 502 | 0.0% | 0.0% | 16 | +4,600 | 2.19% | Q1 2026 | May 15, 2026 |
| Ionic Capital Management LLC | History | No change | 195,939 | 458 | 0.03% | 0.06% | 17 | 0 | 0.0% | Q1 2026 | May 15, 2026 |
| Squarepoint Ops LLC | History | Added to | 194,301 | 454 | 0.0% | 0.0% | 18 | +74,867 | 62.68% | Q1 2026 | May 15, 2026 |
| JANE STREET GROUP, LLC | History | Reduced | 182,645 | 427 | 0.0% | 0.0% | 19 | -14,299 | -7.26% | Q1 2026 | May 12, 2026 |
| MARSHALL WACE, LLP | History | New | 157,072 | 367 | 0.0% | — | 20 | +157,072 | New | Q1 2026 | May 14, 2026 |
| NORTHERN TRUST CORP | History | No change | 120,984 | 283 | 0.0% | 0.0% | 21 | 0 | 0.0% | Q1 2026 | May 14, 2026 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | History | No change | 114,800 | 268 | 0.01% | 0.01% | 22 | 0 | 0.0% | Q1 2026 | May 15, 2026 |
| Shay Capital LLC | History | Added to | 70,354 | 164 | 0.01% | 0.01% | 23 | +10,065 | 16.69% | Q1 2026 | May 15, 2026 |
| Point72 Asset Management, L.P. | History | Added to | 59,668 | 139 | 0.0% | 0.0% | 24 | +16,089 | 36.92% | Q1 2026 | May 15, 2026 |
| Invesco Ltd. | History | Added to | 45,374 | 106 | 0.0% | 0.0% | 25 | +20,669 | 83.66% | Q1 2026 | May 12, 2026 |
| Quadrature Capital Ltd | History | Added to | 40,128 | 93 | 0.0% | 0.0% | 26 | +2,329 | 6.16% | Q1 2026 | May 15, 2026 |
| OMERS ADMINISTRATION Corp | History | Reduced | 39,400 | 92 | 0.0% | 0.0% | 27 | -91,727 | -69.95% | Q1 2026 | May 15, 2026 |
| Capital Asset Advisory Services LLC | History | No change | 32,548 | 92 | 0.0% | 0.0% | 28 | 0 | 0.0% | Q1 2026 | Apr 24, 2026 |
| Verdad Advisers, LP | History | New | 33,455 | 78 | 0.09% | — | 29 | +33,455 | New | Q1 2026 | May 15, 2026 |
| SIMPLEX TRADING, LLC | History | Reduced | 30,304 | 70 | 0.0% | 0.0% | 30 | -5,382 | -15.08% | Q1 2026 | May 14, 2026 |
| Three Seasons Wealth, LLC | History | No change | 30,000 | 70 | 0.03% | 0.01% | 31 | 0 | 0.0% | Q1 2026 | May 05, 2026 |
| DIMENSIONAL FUND ADVISORS LP | History | No change | 29,768 | 69 | 0.0% | 0.0% | 32 | 0 | 0.0% | Q1 2026 | May 07, 2026 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | History | No change | 28,565 | 66 | 0.0% | 0.0% | 33 | 0 | 0.0% | Q1 2026 | May 15, 2026 |
| Vanguard Global Advisers, LLC | History | New | 25,446 | 59 | 0.0% | — | 34 | +25,446 | New | Q1 2026 | May 08, 2026 |
| Schonfeld Strategic Advisors LLC | History | New | 20,314 | 47 | 0.0% | — | 35 | +20,314 | New | Q1 2026 | May 15, 2026 |
| CITIGROUP INC | History | Added to | 19,135 | 44 | 0.0% | — | 36 | +19,118 | 112458.82% | Q1 2026 | May 11, 2026 |
| Assenagon Asset Management S.A. | History | No change | 18,636 | 43 | 0.0% | 0.0% | 37 | 0 | 0.0% | Q1 2026 | Apr 20, 2026 |
| OCCUDO QUANTITATIVE STRATEGIES LP | History | New | 16,421 | 41 | 0.0% | — | 38 | +16,421 | New | Q1 2026 | May 15, 2026 |
| INTREPID FAMILY OFFICE LLC | History | Reduced | 16,279 | 38 | 0.03% | 0.33% | 39 | -148,721 | -90.13% | Q1 2026 | May 15, 2026 |
| Torrey Growth & Income Advisors | History | No change | 17,025 | 37 | 0.02% | 0.01% | 40 | 0 | 0.0% | Q1 2026 | Apr 21, 2026 |
| JONES FINANCIAL COMPANIES LLLP | History | Added to | 7,678 | 17 | 0.0% | 0.0% | 41 | +1,201 | 18.54% | Q1 2026 | May 15, 2026 |
| FNY Investment Advisers, LLC | History | No change | 5,300 | 12 | 0.01% | 0.0% | 42 | 0 | 0.0% | Q1 2026 | Apr 15, 2026 |
| MORGAN STANLEY | History | Added to | 4,552 | 10 | 0.0% | — | 43 | +4,239 | 1354.31% | Q1 2026 | May 15, 2026 |
| UBS Group AG | History | Reduced | 3,009 | 7 | 0.0% | 0.0% | 44 | -113,438 | -97.42% | Q1 2026 | May 05, 2026 |
| Informed Momentum Co LLC | History | Closed out | 0 | 0 | — | 0.06% | — | -218,084 | -100.0% | Q1 2026 | May 13, 2026 |
| SEI INVESTMENTS CO | History | Closed out | 0 | 0 | — | 0.0% | — | -132,010 | -100.0% | Q1 2026 | May 13, 2026 |
| ADAR1 Capital Management, LLC | History | Closed out | 0 | 0 | — | 0.02% | — | -113,839 | -100.0% | Q1 2026 | May 15, 2026 |
| AXXCESS WEALTH MANAGEMENT, LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -32,548 | -100.0% | Q1 2026 | Apr 29, 2026 |
| MILLENNIUM MANAGEMENT LLC | History | Closed out | 0 | 0 | — | 0.0% | — | -24,107 | -100.0% | Q1 2026 | May 15, 2026 |
| XTX Topco Ltd | History | Closed out | 0 | 0 | — | 0.0% | — | -15,175 | -100.0% | Q1 2026 | May 15, 2026 |
| Texas Yale Capital Corp. | History | Closed out | 0 | 0 | — | 0.0% | — | -10,000 | -100.0% | Q1 2026 | May 04, 2026 |
| Tower Research Capital LLC (TRC) | History | Closed out | 0 | 0 | — | 0.0% | — | -7,215 | -100.0% | Q1 2026 | May 15, 2026 |
| JPMORGAN CHASE & CO | History | Reduced | 236 | 0 | — | 0.0% | — | -5,137 | -95.61% | Q1 2026 | May 13, 2026 |
| CULLEN/FROST BANKERS, INC. | History | Closed out | 0 | 0 | — | 0.0% | — | -3,000 | -100.0% | Q1 2026 | May 05, 2026 |
| BANK OF AMERICA CORP /DE/ | History | Closed out | 0 | 0 | — | 0.0% | — | -744 | -100.0% | Q1 2026 | May 15, 2026 |
| Rockefeller Capital Management L.P. | History | Closed out | 0 | 0 | — | — | — | -200 | -100.0% | Q1 2026 | May 14, 2026 |
| Caitong International Asset Management Co., Ltd | History | New | 3 | 0 | — | — | — | +3 | New | Q1 2026 | May 11, 2026 |
| US BANCORP \DE\ | History | No change | 151 | 0 | — | — | — | 0 | 0.0% | Q1 2026 | May 14, 2026 |
| WELLS FARGO & COMPANY/MN | History | No change | 200 | 0 | — | — | — | 0 | 0.0% | Q1 2026 | May 11, 2026 |
| BNP PARIBAS FINANCIAL MARKETS | History | No change | 40 | 0 | — | — | — | 0 | 0.0% | Q1 2026 | May 12, 2026 |
| OSAIC HOLDINGS, INC. | History | No change | 290 | 0 | — | — | — | 0 | 0.0% | Q1 2026 | May 15, 2026 |
| SBI Securities Co., Ltd. | History | No change | 9 | 0 | — | — | — | 0 | 0.0% | Q1 2026 | Apr 27, 2026 |
| SageView Advisory Group, LLC | History | No change | 17 | 0 | — | — | — | 0 | 0.0% | Q4 2025 | Feb 17, 2026 |
| Farther Finance Advisors, LLC | History | No change | 10 | 0 | — | — | — | 0 | 0.0% | Q1 2026 | Apr 07, 2026 |