UPB Short Interest (May 29, 2026 Update)
Short interest for UPB was 3.6M as of May 29, 2026, +7.2% from the prior report.
This page tracks UPB short interest over time, including historical values, changes between reports, and days to cover.
Upstream Bio, Inc. Common Stoc | UPB | Nasdaq | Latest report: May 29, 2026
At the latest settlement date of May 29, 2026, Upstream Bio, Inc. Common Stoc (UPB) showed reported short interest of 3,640,867 shares. That compared with 3,397,759 shares in the prior report, a change of 243.1K shares, or +7.2%. The latest reported days to cover was 6.81, based on average daily volume of 534.4K.
The historical data currently tracked for UPB includes 38 reported entries from October 15, 2024 to May 29, 2026. Over that span, reported short interest has ranged from 230.7K to 4.8M shares.
Extreme edge-case readings may reflect unusually low reported average volume.
| Settlement Date | Short Interest | Prior Short Interest | Change Shares | Change % | Average Daily Volume | Days to Cover |
|---|---|---|---|---|---|---|
| May 29, 2026 | 3,640,867 | 3,397,759 | 243.1K | +7.2% | 534.4K | 6.81 |
| May 15, 2026 | 3,397,759 | 3,223,622 | 174.1K | +5.4% | 507.8K | 6.69 |
| April 30, 2026 | 3,223,622 | 3,022,894 | 200.7K | +6.6% | 564.2K | 5.71 |
| April 15, 2026 | 3,022,894 | 3,435,261 | -412.4K | -12.0% | 576.9K | 5.24 |
| March 31, 2026 | 3,435,261 | 4,752,354 | -1.3M | -27.7% | 991.8K | 3.46 |
| March 13, 2026 | 4,752,354 | 4,086,377 | 666.0K | +16.3% | 1.1M | 4.44 |
| February 27, 2026 | 4,086,377 | 3,529,797 | 556.6K | +15.8% | 2.2M | 1.83 |
| February 13, 2026 | 3,529,797 | 3,183,884 | 345.9K | +10.9% | 2.3M | 1.52 |
| January 30, 2026 | 3,183,884 | 3,451,544 | -267.7K | -7.8% | 574.4K | 5.54 |
| January 15, 2026 | 3,451,544 | 3,486,600 | -35.1K | -1.0% | 652.3K | 5.29 |
| December 31, 2025 | 3,486,600 | 2,983,568 | 503.0K | +16.9% | 606.0K | 5.75 |
| December 15, 2025 | 2,983,568 | 2,773,635 | 209.9K | +7.6% | 534.4K | 5.58 |
| November 28, 2025 | 2,773,635 | 2,994,056 | -220.4K | -7.4% | 541.3K | 5.12 |
| November 14, 2025 | 2,994,056 | 2,929,476 | 64.6K | +2.2% | 383.3K | 7.81 |
| October 31, 2025 | 2,929,476 | 3,336,913 | -407.4K | -12.2% | 371.5K | 7.88 |
| October 15, 2025 | 3,336,913 | 3,564,217 | -227.3K | -6.4% | 324.8K | 10.27 |
| September 15, 2025 | 3,011,653 | 3,097,969 | -86.3K | -2.8% | 662.7K | 4.54 |
| August 29, 2025 | 3,097,969 | 3,160,080 | -62.1K | -2.0% | 352.9K | 8.78 |
| August 15, 2025 | 3,160,080 | 3,080,800 | 79.3K | +2.6% | 491.4K | 6.43 |
| July 31, 2025 | 3,080,800 | 3,781,146 | -700.3K | -18.5% | 536.1K | 5.75 |
| July 15, 2025 | 3,781,146 | 4,109,973 | -328.8K | -8.0% | 267.7K | 14.13 |
| June 30, 2025 | 4,109,973 | 3,610,360 | 499.6K | +13.8% | 718.7K | 5.72 |
| June 13, 2025 | 3,610,360 | 3,685,383 | -75.0K | -2.0% | 358.8K | 10.06 |
| May 30, 2025 | 3,685,383 | 3,746,059 | -60.7K | -1.6% | 386.0K | 9.55 |
| May 15, 2025 | 3,746,059 | 3,940,057 | -194.0K | -4.9% | 362.9K | 10.32 |
| April 30, 2025 | 3,940,057 | 4,067,418 | -127.4K | -3.1% | 296.8K | 13.28 |
| April 15, 2025 | 4,067,418 | 3,895,476 | 171.9K | +4.4% | 299.9K | 13.56 |
| March 31, 2025 | 3,895,476 | 3,712,999 | 182.5K | +4.9% | 251.0K | 15.52 |
| February 28, 2025 | 3,702,588 | 3,462,980 | 239.6K | +6.9% | 212.4K | 17.43 |
| February 14, 2025 | 3,462,980 | 2,717,049 | 745.9K | +27.5% | 292.6K | 11.83 |
| January 31, 2025 | 2,717,049 | 2,392,790 | 324.3K | +13.6% | 240.7K | 11.29 |
| January 15, 2025 | 2,392,790 | 2,302,003 | 90.8K | +3.9% | 254.4K | 9.4 |
| December 31, 2024 | 2,302,003 | 1,217,828 | 1.1M | +89.0% | 645.7K | 3.57 |
| December 13, 2024 | 1,217,828 | 1,205,876 | 12.0K | +1.0% | 231.8K | 5.25 |
| November 29, 2024 | 1,205,876 | 1,039,477 | 166.4K | +16.0% | 246.9K | 4.88 |
| November 15, 2024 | 1,039,477 | 647,123 | 392.4K | +60.6% | 241.4K | 4.31 |
| October 31, 2024 | 647,123 | 230,692 | 416.4K | +180.5% | 343.0K | 1.89 |
| October 15, 2024 | 230,692 | 0 | 230.7K | +100.0% | 379.1K | 1 |