Spero Therapeutics, Inc. (SPRO) ownership: Top institutional holder: GSK plc ($21.51M). Insider activity: Net Seller (0 buys, 12 sells). SEC EDGAR first-party data.
| Holder | Shares | Market Value | Reported |
|---|---|---|---|
| GSK plc | 9190606.00 | $21.51M | 2026-03-31 |
| Pfizer Inc | 2362348.00 | $5.50M | 2026-03-31 |
| VANGUARD GROUP INC | 2083462.00 | $4.85M | 2025-12-31 |
| VANGUARD CAPITAL MANAGEMENT LLC | 1799880.00 | $4.21M | 2026-03-31 |
| RENAISSANCE TECHNOLOGIES LLC | 1189235.00 | $2.78M | 2026-03-31 |
| Alphabet Inc. | 889979.00 | $2.08M | 2026-03-31 |
| TWO SIGMA INVESTMENTS, LP | 885631.00 | $2.07M | 2026-03-31 |
| GEODE CAPITAL MANAGEMENT, LLC | 519922.00 | $1.22M | 2026-03-31 |
| Insider | Transaction | Value | Date |
|---|---|---|---|
| Sell | null | 2026-05-04 | |
| Sell | null | 2026-02-06 | |
| Sell | null | 2026-02-06 | |
| Sell | null | 2026-02-06 | |
| Sell | null | 2026-02-04 | |
| Sell | null | 2026-02-03 | |
| Sell | null | 2026-02-02 | |
| Sell | null | 2026-02-02 |
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Institutional data from SEC Form 13F. Insider data from SEC Form 4. Congressional data from STOCK Act disclosures. Not personalized investment advice.