Filing Flows › Spero Therapeutics (SPRO) › Who owns the stock
Who owns Spero Therapeutics (SPRO) stock
63 funds reported Spero Therapeutics (SPRO) shares in their latest 13F filings, worth $54.6M in all. The largest holder is GSK ($20.3M). Last quarter 28 funds added to their stakes and 25 cut them.
Largest holders (13F)
| Fund | Shares | Value | Change | Quarter |
|---|---|---|---|---|
| GSK | 9,190,606 | $20.3M | unchanged | 2026-06-30 |
| Pfizer | 2,362,348 | $5.3M | unchanged | 2026-06-30 |
| Vanguard Group | 2,083,462 | $4.9M | increase | 2025-12-31 |
| Vanguard Capital Management LLC | 2,036,226 | $4.5M | increase | 2026-06-30 |
| Mackenzie Financial | 1,831,254 | $2.2M | new | 2026-09-30 |
| Renaissance Technologies LLC | 947,904 | $2.1M | decrease | 2026-06-30 |
| Alphabet | 889,979 | $2.0M | unchanged | 2026-06-30 |
| Susquehanna International Group, LLP | 759,290 | $1.7M | increase | 2026-06-30 |
| BlackRock | 594,404 | $1.3M | increase | 2026-06-30 |
| Geode Capital Management, LLC | 566,329 | $1.3M | increase | 2026-06-30 |
| Raymond James Financial | 521,705 | $1.2M | new | 2026-06-30 |
| Two Sigma Investments, LP | 382,814 | $846K | decrease | 2026-06-30 |
| Arrowstreet Capital, Limited Partnership | 332,970 | $736K | new | 2026-06-30 |
| Vanguard Fiduciary Trust | 287,648 | $636K | increase | 2026-06-30 |
| GSA Capital Partners LLP | 285,906 | $632K | increase | 2026-06-30 |
Spero Therapeutics' latest quarter
Spero Therapeutics, Q1 2026: revenue $258K (-96% year over year), net loss $7.2M, operating cash flow $15.9M. The chart follows the revenue to costs, profit and cash.
Questions
Who owns the most SPRO stock?
By the latest 13F filings: GSK ($20.3M); Pfizer ($5.3M); Vanguard Group ($4.9M); Vanguard Capital Management LLC ($4.5M); Mackenzie Financial ($2.2M).
What is the short interest in SPRO?
840,529 shares were sold short at the 2026-10-15 settlement, 5.79% of the float.
Updated Nov 8, 2026. Read automatically from SEC filings and public data; errors are possible. Not investment advice.