PRTA
Prothena Corp Public Ltd CoCompany with tickers: PRTA
CIK
1559053
CUSIP
G72800108
Shares Outstanding
52,353,237
13F Activity (30d)
112 filings
109 filers
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
83/100
Short interest 14.8% of shares — P95
Days to cover 13.9 — P94
Short-volume trend +2.0% — P60
Peer-relative percentile rank across all stocks reporting short interest at the latest settlement date (2026-05-29). Equal-weight mean of the available factors.
Short Interest History
| Settlement Date | Current Position | Previous Position | Change | Days to Cover |
|---|---|---|---|---|
| 2026-05-29 | 7,737,902 | 7,097,854 | +640,048 | 13.85 |
| 2026-05-15 | 7,097,854 | 6,871,465 | +226,389 | 12.96 |
| 2026-04-30 | 6,871,465 | 7,076,832 | -205,367 | 18.33 |
| 2026-04-15 | 7,076,832 | 7,016,080 | +60,752 | 15.33 |
| 2026-03-31 | 7,016,080 | 7,044,790 | -28,710 | 12.32 |
| 2026-03-13 | 7,044,790 | 6,854,767 | +190,023 | 11.20 |
| 2026-02-27 | 6,854,767 | 7,083,043 | -228,276 | 17.22 |
| 2026-02-13 | 7,083,043 | 7,063,694 | +19,349 | 18.12 |
| 2026-01-30 | 7,063,694 | 7,069,471 | -5,777 | 13.90 |
| 2026-01-15 | 7,069,471 | 6,584,532 | +484,939 | 14.42 |
| 2025-12-31 | 6,584,532 | 4,699,126 | +1,885,406 | 7.96 |
| 2025-12-15 | 4,699,126 | 4,639,338 | +59,788 | 6.78 |
| 2025-11-28 | 4,639,338 | 4,657,490 | -18,152 | 9.02 |
| 2025-11-14 | 4,657,490 | 4,144,115 | +513,375 | 7.38 |
| 2025-10-31 | 4,144,115 | 3,857,015 | +287,100 | 8.06 |
| 2025-10-15 | 3,857,015 | 3,845,694 | +11,321 | 5.37 |
| 2025-09-30 | 3,845,694 | 3,763,878 | +81,816 | 5.03 |
| 2025-09-15 | 3,763,878 | 4,055,435 | -291,557 | 4.53 |
| 2025-08-29 | 4,055,435 | 4,184,841 | -129,406 | 3.89 |
| 2025-08-15 | 4,184,841 | 4,374,625 | -189,784 | 3.34 |
| 2025-07-31 | 4,374,625 | 4,757,454 | -382,829 | 5.42 |
| 2025-07-15 | 4,757,454 | 4,330,532 | +426,922 | 5.48 |
| 2025-06-30 | 4,330,532 | 4,655,763 | -325,231 | 1.73 |
| 2025-06-13 | 4,655,763 | 4,414,727 | +241,036 | 3.84 |
Showing 1–24 of 24 settlements