Masimo Corporation Common Stoc | MASI | Nasdaq | Latest report: February 27, 2026
Masimo Corporation Common Stoc (MASI) reported short interest of 3,828,135 shares for the settlement date of February 27, 2026. The prior report showed 3,982,220 shares. That was a change of -154.1K shares, while the latest days-to-cover reading came in at 1 using reported average daily volume of 3.9M.
This page tracks 111 reported short interest entries for MASI from June 15, 2021 through February 27, 2026. Over that period, reported short interest ranged from 728.1K to 6.8M shares.
Reported short interest can change for many reasons, including shifts in sentiment, trading activity, and company-specific events.
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 |
|---|---|---|---|---|---|---|
| February 27, 2026 | 3,828,135 | 3,982,220 | -154.1K | -3.9% | 3.9M | 1 |
| February 13, 2026 | 3,982,220 | 4,112,256 | -130.0K | -3.2% | 647.5K | 6.15 |
| January 30, 2026 | 4,112,256 | 4,129,092 | -16.8K | -0.4% | 796.5K | 5.16 |
| January 15, 2026 | 4,129,092 | 3,926,750 | 202.3K | +5.2% | 751.3K | 5.5 |
| December 31, 2025 | 3,926,750 | 3,968,788 | -42.0K | -1.1% | 711.1K | 5.52 |
| December 15, 2025 | 3,968,788 | 3,821,390 | 147.4K | +3.9% | 821.6K | 4.83 |
| November 28, 2025 | 3,821,390 | 3,823,446 | -2.1K | -0.1% | 710.8K | 5.38 |
| November 14, 2025 | 3,823,446 | 3,815,879 | 7.6K | +0.2% | 1.0M | 3.75 |
| October 31, 2025 | 3,815,879 | 3,849,851 | -34.0K | -0.9% | 538.9K | 7.08 |
| October 15, 2025 | 3,849,851 | 3,809,794 | 40.1K | +1.1% | 679.2K | 5.67 |
| September 15, 2025 | 3,718,952 | 3,535,853 | 183.1K | +5.2% | 592.4K | 6.28 |
| August 29, 2025 | 3,535,853 | 4,107,239 | -571.4K | -13.9% | 623.4K | 5.67 |
| August 15, 2025 | 4,107,239 | 3,268,896 | 838.3K | +25.6% | 1.1M | 3.83 |
| July 31, 2025 | 3,268,896 | 3,249,459 | 19.4K | +0.6% | 540.4K | 6.05 |
| July 15, 2025 | 3,249,459 | 3,030,221 | 219.2K | +7.2% | 531.7K | 6.11 |
| June 30, 2025 | 3,030,221 | 3,280,399 | -250.2K | -7.6% | 589.8K | 5.14 |
| June 13, 2025 | 3,280,399 | 3,125,829 | 154.6K | +4.9% | 657.5K | 4.99 |
| May 30, 2025 | 3,125,829 | 3,029,007 | 96.8K | +3.2% | 610.7K | 5.12 |
| May 15, 2025 | 3,029,007 | 2,582,031 | 447.0K | +17.3% | 861.6K | 3.52 |
| April 30, 2025 | 2,582,031 | 2,793,713 | -211.7K | -7.6% | 409.7K | 6.3 |
| April 15, 2025 | 2,793,713 | 2,900,586 | -106.9K | -3.7% | 817.2K | 3.42 |
| March 31, 2025 | 2,900,586 | 3,354,208 | -453.6K | -13.5% | 510.3K | 5.68 |
| February 28, 2025 | 3,372,513 | 3,005,740 | 366.8K | +12.2% | 750.6K | 4.49 |
| February 14, 2025 | 3,005,740 | 2,911,305 | 94.4K | +3.2% | 326.9K | 9.2 |
| January 31, 2025 | 2,911,305 | 2,820,812 | 90.5K | +3.2% | 541.2K | 5.38 |
| January 15, 2025 | 2,820,812 | 2,741,790 | 79.0K | +2.9% | 479.2K | 5.89 |
| December 31, 2024 | 2,741,790 | 3,449,976 | -708.2K | -20.5% | 471.7K | 5.81 |
| December 13, 2024 | 3,449,976 | 3,203,684 | 246.3K | +7.7% | 410.6K | 8.4 |
| November 29, 2024 | 3,203,684 | 3,339,087 | -135.4K | -4.1% | 563.9K | 5.68 |
| November 15, 2024 | 3,339,087 | 3,348,013 | -8.9K | -0.3% | 779.7K | 4.28 |
| October 31, 2024 | 3,348,013 | 3,580,057 | -232.0K | -6.5% | 511.7K | 6.54 |
| October 15, 2024 | 3,580,057 | 3,469,524 | 110.5K | +3.2% | 1.0M | 3.58 |
| September 30, 2024 | 3,469,524 | 2,924,483 | 545.0K | +18.6% | 937.3K | 3.7 |
| September 13, 2024 | 2,924,483 | 3,932,894 | -1.0M | -25.6% | 461.4K | 6.34 |
| August 30, 2024 | 3,932,894 | 6,754,874 | -2.8M | -41.8% | 352.6K | 11.15 |
| August 15, 2024 | 6,754,874 | 4,711,623 | 2.0M | +43.4% | 899.6K | 7.51 |
| July 31, 2024 | 4,711,623 | 2,583,584 | 2.1M | +82.4% | 865.9K | 5.44 |
| July 15, 2024 | 2,583,584 | 2,667,436 | -83.9K | -3.1% | 606.4K | 4.26 |
| June 28, 2024 | 2,667,436 | 6,495,433 | -3.8M | -58.9% | 617.6K | 4.32 |
| June 14, 2024 | 6,495,433 | 4,881,417 | 1.6M | +33.1% | 818.0K | 7.94 |
| May 31, 2024 | 4,881,417 | 3,081,495 | 1.8M | +58.4% | 837.7K | 5.83 |
| May 15, 2024 | 3,081,495 | 3,891,658 | -810.2K | -20.8% | 971.3K | 3.17 |
| April 30, 2024 | 3,891,658 | 4,041,399 | -149.7K | -3.7% | 289.3K | 13.45 |
| April 15, 2024 | 4,041,399 | 4,230,124 | -188.7K | -4.5% | 453.9K | 8.9 |
| March 28, 2024 | 4,230,124 | 4,653,720 | -423.6K | -9.1% | 596.0K | 7.1 |
| March 15, 2024 | 4,653,720 | 4,750,117 | -96.4K | -2.0% | 574.2K | 8.1 |
| February 29, 2024 | 4,750,117 | 5,112,378 | -362.3K | -7.1% | 621.0K | 7.65 |
| February 15, 2024 | 5,112,378 | 4,941,489 | 170.9K | +3.5% | 476.3K | 10.73 |
| January 31, 2024 | 4,941,489 | 4,558,851 | 382.6K | +8.4% | 679.9K | 7.27 |
| December 29, 2023 | 4,381,324 | 4,453,814 | -72.5K | -1.6% | 813.9K | 5.38 |
| December 15, 2023 | 4,453,814 | 4,498,487 | -44.7K | -1.0% | 918.6K | 4.85 |
| November 30, 2023 | 4,498,487 | 4,154,545 | 343.9K | +8.3% | 779.1K | 5.77 |
| November 15, 2023 | 4,154,545 | 3,864,061 | 290.5K | +7.5% | 1.1M | 3.71 |
| October 31, 2023 | 3,884,074 | 3,991,445 | -107.4K | -2.7% | 1.1M | 3.65 |
| October 13, 2023 | 3,991,445 | 3,990,264 | 1.2K | +0.0% | 798.5K | 5 |
| September 29, 2023 | 3,990,264 | 3,913,336 | 76.9K | +2.0% | 1.0M | 3.88 |
| September 15, 2023 | 3,913,336 | 3,508,706 | 404.6K | +11.5% | 1.2M | 3.38 |
| August 31, 2023 | 3,508,706 | 3,679,130 | -170.4K | -4.6% | 835.8K | 4.2 |
| August 15, 2023 | 3,679,130 | 3,446,780 | 232.3K | +6.7% | 988.2K | 3.72 |
| July 31, 2023 | 3,446,780 | 2,564,988 | 881.8K | +34.4% | 1.8M | 1.95 |
| July 14, 2023 | 2,564,988 | 2,545,267 | 19.7K | +0.8% | 546.5K | 4.69 |
| June 30, 2023 | 2,545,267 | 2,491,429 | 53.8K | +2.2% | 443.9K | 5.73 |
| June 15, 2023 | 2,491,429 | 1,882,950 | 608.5K | +32.3% | 457.2K | 5.45 |
| May 31, 2023 | 1,882,950 | 1,066,725 | 816.2K | +76.5% | 517.4K | 3.64 |
| May 15, 2023 | 1,066,600 | 865,584 | 201.0K | +23.2% | 526.7K | 2.02 |
| April 28, 2023 | 865,584 | 854,735 | 10.8K | +1.3% | 292.5K | 2.96 |
| April 14, 2023 | 854,735 | 734,169 | 120.6K | +16.4% | 316.7K | 2.7 |
| March 31, 2023 | 734,169 | 893,965 | -159.8K | -17.9% | 264.8K | 2.77 |
| March 15, 2023 | 893,965 | 887,521 | 6.4K | +0.7% | 350.9K | 2.55 |
| February 28, 2023 | 887,521 | 950,528 | -63.0K | -6.6% | 315.3K | 2.81 |
| February 15, 2023 | 950,528 | 1,128,812 | -178.3K | -15.8% | 275.3K | 3.45 |
| January 31, 2023 | 1,128,812 | 1,464,532 | -335.7K | -22.9% | 420.9K | 2.68 |
| January 13, 2023 | 1,464,532 | 1,536,675 | -72.1K | -4.7% | 439.6K | 3.33 |
| December 30, 2022 | 1,536,675 | 1,949,183 | -412.5K | -21.2% | 402.8K | 3.81 |
| December 15, 2022 | 1,949,183 | 2,241,458 | -292.3K | -13.0% | 525.3K | 3.71 |
| November 30, 2022 | 2,241,458 | 2,633,138 | -391.7K | -14.9% | 603.3K | 3.72 |
| November 15, 2022 | 2,633,138 | 2,914,649 | -281.5K | -9.7% | 768.7K | 3.43 |
| October 31, 2022 | 2,914,649 | 3,081,656 | -167.0K | -5.4% | 699.8K | 4.16 |
| October 14, 2022 | 3,081,656 | 3,430,762 | -349.1K | -10.2% | 742.6K | 4.15 |
| September 30, 2022 | 3,430,762 | 3,288,942 | 141.8K | +4.3% | 705.9K | 4.86 |
| September 15, 2022 | 3,288,942 | 3,446,655 | -157.7K | -4.6% | 889.0K | 3.7 |
| August 31, 2022 | 3,446,655 | 4,103,992 | -657.3K | -16.0% | 971.4K | 3.55 |
| August 15, 2022 | 4,103,992 | 3,530,587 | 573.4K | +16.2% | 1.4M | 2.85 |
| July 29, 2022 | 3,530,587 | 2,892,301 | 638.3K | +22.1% | 860.5K | 4.1 |
| July 15, 2022 | 2,892,301 | 2,699,871 | 192.4K | +7.1% | 450.1K | 6.43 |
| June 30, 2022 | 2,699,871 | 2,780,085 | -80.2K | -2.9% | 634.8K | 4.25 |
| June 15, 2022 | 2,780,085 | 3,387,656 | -607.6K | -17.9% | 619.2K | 4.49 |
| May 31, 2022 | 3,387,656 | 3,342,917 | 44.7K | +1.3% | 1.2M | 2.85 |
| May 13, 2022 | 3,342,917 | 2,316,903 | 1.0M | +44.3% | 1.5M | 2.28 |
| April 29, 2022 | 2,316,903 | 2,204,825 | 112.1K | +5.1% | 718.7K | 3.22 |
| April 14, 2022 | 2,204,825 | 1,504,298 | 700.5K | +46.6% | 1.0M | 2.19 |
| March 31, 2022 | 1,504,298 | 915,768 | 588.5K | +64.3% | 927.1K | 1.62 |
| March 15, 2022 | 915,768 | 728,142 | 187.6K | +25.8% | 968.3K | 1 |
| February 28, 2022 | 728,142 | 1,344,804 | -616.7K | -45.9% | 2.5M | 1 |
| February 15, 2022 | 1,344,804 | 1,319,151 | 25.7K | +1.9% | 363.7K | 3.7 |
| January 31, 2022 | 1,319,151 | 1,560,225 | -241.1K | -15.4% | 543.8K | 2.43 |
| January 14, 2022 | 1,560,225 | 1,338,345 | 221.9K | +16.6% | 393.7K | 3.96 |
| December 31, 2021 | 1,338,345 | 1,483,972 | -145.6K | -9.8% | 224.4K | 5.97 |
| December 15, 2021 | 1,483,972 | 1,582,940 | -99.0K | -6.2% | 231.5K | 6.41 |
| November 30, 2021 | 1,582,940 | 1,619,748 | -36.8K | -2.3% | 256.1K | 6.18 |
| November 15, 2021 | 1,619,748 | 1,467,560 | 152.2K | +10.4% | 215.5K | 7.52 |
| October 29, 2021 | 1,467,560 | 1,584,481 | -116.9K | -7.4% | 295.4K | 4.97 |
| October 15, 2021 | 1,584,481 | 1,605,675 | -21.2K | -1.3% | 200.5K | 7.9 |
| September 30, 2021 | 1,605,675 | 1,434,842 | 170.8K | +11.9% | 266.3K | 6.03 |
| September 15, 2021 | 1,434,842 | 1,569,214 | -134.4K | -8.6% | 218.6K | 6.56 |
| August 31, 2021 | 1,569,214 | 1,642,462 | -73.2K | -4.5% | 208.5K | 7.53 |
| August 13, 2021 | 1,642,462 | 1,635,816 | 6.6K | +0.4% | 167.6K | 9.8 |
| July 30, 2021 | 1,635,816 | 1,495,959 | 139.9K | +9.3% | 317.8K | 5.15 |
| July 15, 2021 | 1,495,959 | 1,349,210 | 146.7K | +10.9% | 289.5K | 5.17 |
| June 30, 2021 | 1,349,210 | 1,254,678 | 94.5K | +7.5% | 429.0K | 3.15 |
| June 15, 2021 | 1,254,678 | 1,294,300 | -39.6K | -3.1% | 341.5K | 3.67 |