ATRA · Atara Biotherapeutics, Inc. · Short Interest
Substantial doubt about the company's ability to continue as a going concern.
“Our existing cash, cash equivalents and short-term investments as of June 30, 2026 will not be sufficient to fund our planned operations for at least the next twelve months from the date of issuance of these financial statements. These conditions raise substantial doubt about our ability to continue as a going concern for at least 12 months after the issuance of the accompanying condensed consolidated financial statements.”View the 10-Q filed Aug 12, 2026
Shares sold short and not yet covered, reported twice monthly. Days to cover is the reported short position divided by average daily volume.
ATRA Latest Reported Short Interest
FINRA reported 427,435 ATRA shares sold short as of the August 31, 2026 settlement date, a decrease of 49,833 shares. Days to cover was 11.07 based on FINRA's reported average daily volume.
Official FINRA short-interest data · share counts are restated for subsequent splits of this listing
ATRA Short Interest Forecast
Equibles' model estimates 409,228 shares sold short for the September 15, 2026 settlement, -4.3% versus the latest reported position, with a likely range of 349,325 to 461,899 shares. This model prediction uses FINRA data through September 11, 2026; FINRA's official release is expected September 24, 2026.
Expected Sep 15 short interest
as of Sep 11 High confidence 75% chance it fallsPositioning score 60.7 + catalyst boost 0 (total capped at 100). This is a screening index, not a probability of a squeeze.
Method and coverage limits
Factor percentiles compare eligible primary operating-company stocks reporting short interest at the latest settlement date (2026-08-31). The weighted mean uses short interest 30%, days to cover 20%, price vs VWAP 15%, short-volume trend 15%, short-interest change 10%, and fails-to-deliver 10%. Missing factors redistribute their weight; incomplete coverage is not evidence of low risk. Price, volume, and earnings boosts add 10 each, capped at 20.
Shares outstanding are not free float. Borrow fees, utilization, lendable supply, recalls, and dealer inventory are not measured. Short-sale volume does not measure the change in open shorts; fails to deliver are not a borrow-cost measurement; price vs VWAP does not establish short sellers' entry prices. Earnings can move prices in either direction.
The weights are judgment-based, not calibrated to future squeeze outcomes. The separate options assessment below does not change this universe ranking.
Options positioning & squeeze sensitivity
Nearest expiration after today within 30 calendar days; same-day expirations and later maturities are excluded.
No active listed options were found.
Open interest has both a buyer and a seller; it does not reveal dealer hedge direction. Gross gamma sums both calls and puts without netting and uses a local 1% price-change approximation. It measures sensitivity, not predicted buying or a squeeze probability.
Assessment prepared 2026-09-13 17:36 UTC. Options model values may come from a cached snapshot; their original computation time is not supplied. Open interest has its own effective date.
Short Interest History
| Settlement Date | Current Position | Previous Position | Change | Days to Cover |
|---|---|---|---|---|
|
2026-09-30
Scheduled
FINRA publishes Oct 9
|
— | — | — | — |
|
2026-09-15
Scheduled
FINRA publishes Sep 24
|
— | — | — | — |
| 2026-08-31 | 427,435 | 477,268 | -49,833 | 11.07 |
| 2026-08-14 | 477,268 | 536,897 | -59,629 | 9.21 |
| 2026-07-31 | 536,897 | 577,635 | -40,738 | 9.39 |
| 2026-07-15 | 577,635 | 361,520 | +216,115 | 6.24 |
| 2026-06-30 | 361,520 | 492,405 | -130,885 | 3.95 |
| 2026-06-15 | 492,405 | 484,391 | +8,014 | 6.27 |
| 2026-05-29 | 484,391 | 546,470 | -62,079 | 2.91 |
| 2026-05-15 | 546,470 | 306,093 | +240,377 | 1.00 |
| 2026-04-30 | 306,093 | 317,953 | -11,860 | 6.10 |
| 2026-04-15 | 317,953 | 327,066 | -9,113 | 4.10 |
| 2026-03-31 | 327,066 | 313,290 | +13,776 | 3.01 |
| 2026-03-13 | 313,290 | 330,524 | -17,234 | 1.00 |
| 2026-02-27 | 330,524 | 209,287 | +121,237 | 2.13 |
| 2026-02-13 | 209,287 | 282,525 | -73,238 | 2.40 |
| 2026-01-30 | 282,525 | 1,016,616 | -734,091 | 1.00 |
| 2026-01-15 | 1,016,616 | 169,201 | +847,415 | 1.00 |
| 2025-12-31 | 169,201 | 166,856 | +2,345 | 2.56 |
| 2025-12-15 | 166,856 | 164,713 | +2,143 | 2.01 |
| 2025-11-28 | 164,713 | 176,777 | -12,064 | 2.79 |
| 2025-11-14 | 176,777 | 168,549 | +8,228 | 2.37 |
| 2025-10-31 | 168,549 | 128,849 | +39,700 | 3.72 |
| 2025-10-15 | 128,849 | 149,590 | -20,741 | 2.11 |
| 2025-09-30 | 149,590 | 161,507 | -11,917 | 2.51 |
| 2025-09-15 | 161,507 | 173,825 | -12,318 | 3.51 |
Full FINRA short interest reporting calendar