BIIB short interest
Biogen Inc. · Healthcare · Drug Manufacturers - General · settlement date 2026-09-30
| Shares short | 5,965,892 |
|---|---|
| Change vs prior report | 148,095 (+2.5%) |
| Change over six months | +55.9% |
| Days to cover | 4.87 (sector: 3.78) |
| Average daily volume | 1,225,961 |
| Rank in Healthcare | #429 of 922 by days to cover |
BIIB short interest, last 12 months
| Settlement | Shares short | Change | Days to cover | Avg daily volume |
|---|---|---|---|---|
| 2026-09-30 | 5,965,892 | +2.5% | 4.87 | 1,225,961 |
| 2026-09-15 | 5,817,797 | +1.6% | 7.59 | 766,507 |
| 2026-08-31 | 5,726,631 | +10.3% | 8.66 | 661,593 |
| 2026-08-14 | 5,190,555 | -4.8% | 6.13 | 847,068 |
| 2026-07-31 | 5,453,901 | -9.1% | 4.73 | 1,153,245 |
| 2026-07-15 | 5,999,133 | +4.8% | 3.45 | 1,739,800 |
| 2026-06-30 | 5,723,194 | +10.3% | 4.14 | 1,382,477 |
| 2026-06-15 | 5,188,836 | +8.8% | 5.65 | 918,726 |
| 2026-05-29 | 4,771,495 | +0.9% | 4.49 | 1,063,313 |
| 2026-05-15 | 4,729,958 | +5.7% | 4.21 | 1,122,410 |
| 2026-04-30 | 4,475,470 | +1.4% | 3.59 | 1,247,291 |
| 2026-04-15 | 4,414,958 | +15.4% | 3.07 | 1,439,919 |
| 2026-03-31 | 3,826,441 | -11.7% | 3.47 | 1,104,246 |
| 2026-03-13 | 4,334,795 | +3.1% | 5.15 | 842,122 |
| 2026-02-27 | 4,202,912 | -7.5% | 4.63 | 908,274 |
| 2026-02-13 | 4,545,171 | -3.1% | 2.45 | 1,854,090 |
| 2026-01-30 | 4,692,637 | +0.3% | 3.62 | 1,296,294 |
| 2026-01-15 | 4,678,036 | +4.7% | 2.62 | 1,782,177 |
| 2025-12-31 | 4,466,337 | -32.2% | 1.67 | 2,674,703 |
| 2025-12-15 | 6,590,958 | -2.8% | 3.67 | 1,797,983 |
| 2025-11-28 | 6,777,473 | +10.4% | 3.26 | 2,080,199 |
| 2025-11-14 | 6,140,844 | +8.8% | 3.19 | 1,922,869 |
| 2025-10-31 | 5,644,654 | +8.7% | 3.60 | 1,566,934 |
| 2025-10-15 | 5,191,008 | +6.4% | 2.69 | 1,926,364 |
| 2025-09-30 | 4,880,043 | -4.8% | 2.98 | 1,636,581 |
import finzdata as yf
yf.Ticker("BIIB").short_interest # every report since 2017
yf.Client().short_interest(["BIIB"], start="2018-01-01")Healthcare short interest · BIIB price history · Who owns BIIB · All short interest