SPRO — Spero Therapeutics, Inc.
Price · 2024-08-26 → 2026-08-21
499 daily closes shownAnonymous view is capped at two years of history. A free account extends it to five, and Pro opens the whole archive back to 2017-11-02.
Performance
Technicals
Others in Healthcare
Measured signals that fired on SPRO
| date | signal | measured base rate |
|---|---|---|
| 2026-06-16 | Short volume far above its own normal short | -0.76% over 21 days · t = -2.79 · n = 5,897 statistically distinguishable from its control group |
| 2026-05-12 | Short volume far above its own normal short | -0.76% over 21 days · t = -2.79 · n = 5,897 statistically distinguishable from its control group |
Excess return against a matched control group, on a point-in-time universe that includes delisted companies. Most families do not survive that. How the measurement works →
Insider transactions (Form 4)
| date | insider | what | shares | price | value |
|---|---|---|---|---|---|
| 2026-08-03 | Zack Debra Chief Medical Officer | Grant or award 10b5-1 plan | 162.3K | 0.00 | 0 |
| 2026-06-23 | Jackson Scott Thomas Director | Grant or award | 10.0K | 0.00 | 0 |
| 2026-06-23 | Pottage John C Jr Director | Grant or award | 10.0K | 0.00 | 0 |
| 2026-06-23 | Deshpande Milind Director | Grant or award | 10.0K | 0.00 | 0 |
| 2026-06-23 | THOMAS FRANK E Director | Grant or award | 10.0K | 0.00 | 0 |
| 2026-06-23 | VINK PATRICK V.J.J. Director | Grant or award | 10.0K | 0.00 | 0 |
| 2026-06-23 | Smith Cynthia Director | Grant or award | 10.0K | 0.00 | 0 |
| 2026-06-23 | Tregoning Kathleen Director | Grant or award | 10.0K | 0.00 | 0 |
| 2026-05-04 | Rajavelu Esther See Remarks | Open-market sale | 25.2K | 2.51 | 63.4K |
| 2026-02-06 | Rajavelu Esther See Remarks | Open-market sale | 50.8K | 2.36 | 119.9K |
Open-market purchases (code P) are the informative ones. Grants, option exercises and tax withholding are compensation mechanics, not decisions. How to read a Form 4 →
Largest institutional holders
| manager | value | shares |
|---|---|---|
| GSK plc | 21.5M | 9.2M |
| Pfizer Inc | 5.5M | 2.4M |
| VANGUARD CAPITAL MANAGEMENT LLC | 4.2M | 1.8M |
| RENAISSANCE TECHNOLOGIES LLC | 2.8M | 1.2M |
| Alphabet Inc. | 2.1M | 890.0K |
| TWO SIGMA INVESTMENTS, LP | 2.1M | 885.6K |
| Anson Funds Management LP | 2.0M | 843.9K |
| GEODE CAPITAL MANAGEMENT, LLC | 1.2M | 519.9K |
| BlackRock, Inc. | 1.0M | 433.2K |
| CITADEL ADVISORS LLC | 880.9K | 376.5K |
13F positions as of 2026-03-31, filed up to 45 days after quarter end. Long-only US equity — shorts and derivatives never appear. What 13F does and does not show →
Latest SEC filings
| form | filed | period | |
|---|---|---|---|
| 8-K | 2026-08-12 | 2026-08-12 | on EDGAR ↗ |
| 10-Q | 2026-08-12 | 2026-06-30 | on EDGAR ↗ |
| 4 | 2026-08-06 | 2026-08-03 | on EDGAR ↗ |
| 3 | 2026-08-06 | 2026-08-03 | on EDGAR ↗ |
| 8-K | 2026-07-14 | 2026-07-08 | on EDGAR ↗ |
| 4 | 2026-06-25 | 2026-06-23 | on EDGAR ↗ |
| 4 | 2026-06-25 | 2026-06-23 | on EDGAR ↗ |
| 4 | 2026-06-25 | 2026-06-23 | on EDGAR ↗ |
Short selling
This is off-exchange short volume, not short interest: it is flow, not position, and 40–50% is normal because market makers short to fill your buy. Why that number misleads →
Recent headlines
- Spero Therapeutics (SPRO) Q2 2026 Earnings Call Transcript · 2026-08-19
- Spero Therapeutics, Inc. (SPRO) filed form 8-K · 2026-08-12 · SEC EDGAR
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