SPRO · Spero Therapeutics, Inc.
$1.22
+0.06 (+4.74%)
Market Cap
$67.17M
Shares
57.90M
Total shares sold short and not yet covered, reported to FINRA by broker-dealers and published twice a month (bi-monthly). Days to cover divides the short position by average daily volume; a high value (above 5) can signal short-squeeze potential.
Short Squeeze Score
58/100
Short interest 4.9% of shares — P73
Days to cover 1.0 — P31
Price vs VWAP -46.1% — P4
Short-volume trend +12.8% — P87
Short interest change +56.4% — P89
Worst FTD 0.08% of shares — P73
Peer-relative percentile rank across all stocks reporting short interest at the latest settlement date (2026-06-30). Weighted mean of the available factors (short interest 30%, days to cover 20%, price vs VWAP 15%, short-volume trend 15%, short-interest change 10%, fails-to-deliver 10%) plus catalyst boosts (price spike, volume surge, earnings within days), capped at +20 and clamped to 100.
Short Interest History
| Settlement Date | Current Position | Previous Position | Change | Days to Cover |
|---|---|---|---|---|
| 2026-06-30 | 2,864,850 | 1,831,713 | +1,033,137 | 1.04 |
| 2026-06-15 | 1,831,713 | 1,706,545 | +125,168 | 2.25 |
| 2026-05-29 | 1,706,545 | 1,647,297 | +59,248 | 1.96 |
| 2026-05-15 | 1,647,297 | 1,179,702 | +467,595 | 2.61 |
| 2026-04-30 | 1,179,702 | 737,720 | +441,982 | 3.06 |
| 2026-04-15 | 737,720 | 605,311 | +132,409 | 1.39 |
| 2026-03-31 | 605,311 | 537,411 | +67,900 | 1.86 |
| 2026-03-13 | 537,411 | 574,027 | -36,616 | 1.72 |
| 2026-02-27 | 574,027 | 715,694 | -141,667 | 2.12 |
| 2026-02-13 | 715,694 | 941,659 | -225,965 | 1.68 |
| 2026-01-30 | 941,659 | 1,039,613 | -97,954 | 4.01 |
| 2026-01-15 | 1,039,613 | 946,767 | +92,846 | 4.43 |
| 2025-12-31 | 946,767 | 1,056,013 | -109,246 | 3.85 |
| 2025-12-15 | 1,056,013 | 825,698 | +230,315 | 3.51 |
| 2025-11-28 | 825,698 | 615,735 | +209,963 | 2.14 |
| 2025-11-14 | 615,735 | 476,137 | +139,598 | 1.05 |
| 2025-10-31 | 476,137 | 315,715 | +160,422 | 1.00 |
| 2025-10-15 | 315,715 | 549,473 | -233,758 | 1.00 |
| 2025-09-30 | 549,473 | 458,620 | +90,853 | 2.06 |
| 2025-09-15 | 458,620 | 503,998 | -45,378 | 1.32 |
| 2025-08-29 | 503,998 | 927,158 | -423,160 | 1.35 |
| 2025-08-15 | 927,158 | 1,379,953 | -452,795 | 1.00 |
| 2025-07-31 | 1,379,953 | 1,217,101 | +162,852 | 2.25 |
Showing 1–23 of 23 settlements