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Personalis, Inc.

PSNL
Exchange
Nasdaq
Industry
Services-Medical Laboratories
SEC CIK
0001527753

In the last 90 days, Personalis, Inc. insiders filed 0 open-market purchases and 5 sales; 160 institutions reported holding it in 13F filings for Q2 2026, worth $1.14B in total; ARK Invest is the only superinvestor holding it.

Four kinds of short-selling data, each measuring something different:

  • Short interest: shares sold short and not yet bought back, as of a settlement date. FINRA publishes it twice a month, about eight business days after the settlement date.
  • Daily short volume: shares sold short each day in off-exchange trades reported to FINRA. It counts trades, not open positions, and is published the next day.
  • Fails-to-deliver: shares not delivered by the settlement date. The SEC publishes them twice a month, about two weeks late.
  • ATS (dark pool) volume: weekly volume on alternative trading systems and other off-exchange venues. FINRA publishes it two to four weeks after the week.

More in the glossary.

Short interest

Shares sold short and not yet bought back, from FINRA, on every settlement date in the last two years.

Short interest
6.75M
Shares, settlement Oct 30, 2026
Change
−45.6K
−0.7% vs. Oct 15, 2026
Days to cover
3.34
Short interest ÷ average daily volume
Average daily volume
2.02M
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 3,235,603 sharesNov 15, 2024: 2,851,636 sharesNov 29, 2024: 3,020,165 sharesDec 13, 2024: 2,971,527 sharesDec 31, 2024: 3,307,917 sharesJan 15, 2025: 3,513,322 sharesJan 31, 2025: 3,527,599 sharesFeb 14, 2025: 3,876,937 sharesFeb 28, 2025: 3,777,329 sharesMar 14, 2025: 4,336,671 sharesMar 31, 2025: 4,337,239 sharesApr 15, 2025: 4,409,569 sharesApr 30, 2025: 3,861,028 sharesMay 15, 2025: 4,252,203 sharesMay 30, 2025: 3,875,344 sharesJun 13, 2025: 3,862,297 sharesJun 30, 2025: 6,137,113 sharesJul 15, 2025: 6,848,626 sharesJul 31, 2025: 7,180,342 sharesAug 15, 2025: 7,526,460 sharesAug 29, 2025: 8,146,585 sharesSep 15, 2025: 7,549,472 sharesSep 30, 2025: 8,317,714 sharesOct 15, 2025: 7,666,934 sharesOct 31, 2025: 7,014,430 sharesNov 14, 2025: 7,736,272 sharesNov 28, 2025: 7,773,493 sharesDec 15, 2025: 8,180,125 sharesDec 31, 2025: 8,208,568 sharesJan 15, 2026: 8,735,238 sharesJan 30, 2026: 8,813,216 sharesFeb 13, 2026: 10,685,978 sharesFeb 27, 2026: 11,206,564 sharesMar 13, 2026: 11,167,937 sharesMar 31, 2026: 11,755,231 sharesApr 15, 2026: 12,394,050 sharesApr 30, 2026: 13,104,403 sharesMay 15, 2026: 13,734,814 sharesMay 29, 2026: 12,825,386 sharesJun 15, 2026: 11,104,630 sharesJun 30, 2026: 11,306,678 sharesJul 15, 2026: 11,097,287 sharesJul 31, 2026: 8,714,008 sharesAug 14, 2026: 8,398,426 sharesAug 31, 2026: 8,384,040 sharesSep 15, 2026: 8,266,193 sharesSep 30, 2026: 8,427,731 sharesOct 15, 2026: 6,793,284 sharesOct 30, 2026: 6,747,693 shares
Short interest in PSNL by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 20266.75M−45.6K−0.7%2.02M3.34
Oct 15, 20266.79M−1.63M−19.4%2.57M2.64
Sep 30, 20268.43M+161.5K+2.0%1.95M4.33
Sep 15, 20268.27M−117.8K−1.4%2.33M3.55
Aug 31, 20268.38M−14.4K−0.2%4.67M1.80
Aug 14, 20268.40M−315.6K−3.6%2.33M3.61
Jul 31, 20268.71M−2.38M−21.5%5.15M1.69
Jul 15, 202611.1M−209.4K−1.9%4.75M2.34
Jun 30, 202611.3M+202.0K+1.8%4.07M2.78
Jun 15, 202611.1M−1.72M−13.4%3.09M3.60
May 29, 202612.8M−909.4K−6.6%2.98M4.30
May 15, 202613.7M+630.4K+4.8%2.43M5.64
Apr 30, 202613.1M+710.4K+5.7%2.26M5.80
Apr 15, 202612.4M+638.8K+5.4%1.31M9.48
Mar 31, 202611.8M+587.3K+5.3%1.59M7.40
Mar 13, 202611.2M−38.6K−0.3%1.74M6.43
Feb 27, 202611.2M+520.6K+4.9%1.28M8.75
Feb 13, 202610.7M+1.87M+21.3%1.25M8.56
Jan 30, 20268.81M+78.0K+0.9%1.52M5.81
Jan 15, 20268.74M+526.7K+6.4%1.17M7.49
Dec 31, 20258.21M+28.4K+0.4%1.35M6.10
Dec 15, 20258.18M+406.6K+5.2%1.46M5.61
Nov 28, 20257.77M+37.2K+0.5%1.73M4.51
Nov 14, 20257.74M+721.8K+10.3%1.91M4.04
Oct 31, 20257.01M−652.5K−8.5%1.39M5.04
Oct 15, 20257.67M−650.8K−7.8%1.05M7.30
Sep 30, 20258.32M+768.2K+10.2%855.8K9.72
Sep 15, 20257.55M−597.1K−7.3%904.2K8.35
Aug 29, 20258.15M+620.1K+8.2%803.1K10.14
Aug 15, 20257.53M+346.1K+4.8%1.26M5.96
Jul 31, 20257.18M+331.7K+4.8%880.2K8.16
Jul 15, 20256.85M+711.5K+11.6%1.44M4.76
Jun 30, 20256.14M+2.27M+58.9%2.25M2.73
Jun 13, 20253.86M−13.0K−0.3%908.9K4.25
May 30, 20253.88M−376.9K−8.9%519.7K7.46
May 15, 20254.25M+391.2K+10.1%903.8K4.70
Apr 30, 20253.86M−548.5K−12.4%573.5K6.73
Apr 15, 20254.41M+72.3K+1.7%695.5K6.34
Mar 31, 20254.34M+5680.0%807.6K5.37
Mar 14, 20254.34M+559.3K+14.8%1.14M3.80
Feb 28, 20253.78M−99.6K−2.6%1.31M2.88
Feb 14, 20253.88M+349.3K+9.9%985.2K3.94
Jan 31, 20253.53M+14.3K+0.4%1.30M2.72
Jan 15, 20253.51M+205.4K+6.2%1.01M3.48
Dec 31, 20243.31M+336.4K+11.3%1.97M1.68
Dec 13, 20242.97M−48.6K−1.6%512.1K5.80
Nov 29, 20243.02M+168.5K+5.9%732.8K4.12
Nov 15, 20242.85M−384.0K−11.9%1.17M2.44
Oct 31, 20243.24M+116.9K+3.8%419.4K7.72

Fails-to-deliver

Shares that weren't delivered by the settlement date, from the SEC, for the last 30 dates with fails. The price is the previous day's closing price published by the SEC.

Fails-to-deliver in PSNL by settlement date
Settlement dateSharesPriceValue
Oct 7, 20261,805$16.03$28.9K
Oct 5, 202652,274$16.28$851.0K
Sep 30, 20263,003$16.35$49.1K
Sep 23, 20263,560$16.36$58.2K
Sep 18, 2026737$16.23$12.0K
Sep 8, 2026134,956$17.20$2.32M
Aug 31, 2026300$17.07$5.12K
Aug 25, 202618$17.06$307.08
Aug 12, 2026107,359$14.02$1.51M
Aug 6, 20261,178$13.52$15.9K
Aug 4, 202674,598$13.20$984.7K
Aug 3, 202678,408$12.66$992.6K
Jul 22, 2026519,585$13.44$6.98M
Jul 17, 2026496$15.58$7.73K
Jul 16, 20264,850$15.79$76.6K
Jul 14, 20261,934$15.04$29.1K
Jul 8, 2026367$13.98$5.13K
Jul 7, 202610,378$14.34$148.8K
Jul 1, 2026757$13.40$10.1K
Jun 30, 202625,614$13.75$352.2K
Jun 26, 202615,844$12.59$199.5K
Jun 25, 202622,178$11.36$251.9K
Jun 22, 20261,150$10.54$12.1K
Jun 17, 202613,164$9.69$127.6K
Jun 16, 20262,592$9.79$25.4K
Jun 15, 20262,910$9.59$27.9K
Jun 12, 2026515$9.42$4.85K
Jun 11, 20263,424$9.61$32.9K
Jun 10, 2026280,024$9.75$2.73M
Jun 5, 2026341$12.10$4.13K

Daily short volume

Off-exchange short-sale volume, not short interest: shares sold short each day in trades reported to FINRA, for the last 30 trading days.

The short volume ratio isn't a sentiment gauge: market makers sell short to fill buy orders and to hedge, so short sales are usually about half of off-exchange volume.

Off-exchange short volume in PSNL by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 11, 2026173,765300411,92842.2%
Nov 10, 2026129,60910553,85823.4%
Nov 9, 2026304,74512,741710,92642.9%
Nov 6, 2026358,9355,3591,083,40333.1%
Nov 5, 2026659,8442,1471,147,82157.5%
Nov 4, 2026347,36901,045,11333.2%
Nov 3, 2026363,4012331,227,25229.6%
Nov 2, 2026313,174769818,72838.3%
Oct 30, 2026624,118215897,30669.6%
Oct 29, 2026159,0290261,70660.8%
Oct 28, 2026263,8550435,16260.6%
Oct 27, 2026404,3860648,27762.4%
Oct 26, 2026129,091315237,42754.4%
Oct 23, 2026179,002273331,20454.0%
Oct 22, 2026705,1670959,14973.5%
Oct 21, 2026561,19501,059,10853.0%
Oct 20, 2026542,03101,049,97451.6%
Oct 19, 2026653,2231,4001,484,05244.0%
Oct 16, 2026588,0581991,612,16736.5%
Oct 15, 2026325,0352,111863,77637.6%
Oct 14, 2026472,9936001,619,08929.2%
Oct 13, 2026436,02201,969,25722.1%
Oct 12, 2026278,76701,228,25422.7%
Oct 9, 2026156,0670671,27423.2%
Oct 8, 2026265,1840556,79047.6%
Oct 7, 2026700,3617,2901,725,52540.6%
Oct 6, 2026873,6093183,356,80126.0%
Oct 5, 2026105,7020266,29739.7%
Oct 2, 2026265,282100444,46859.7%
Oct 1, 2026265,7760693,35838.3%

ATS (dark pool) volume

Weekly volume on alternative trading systems (ATS) and other off-exchange (OTC) venues, from FINRA, for the last 12 weeks. ATS share is ATS volume ÷ (ATS + OTC volume), not a share of all trading.

Weekly ATS and OTC volume in PSNL
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 5, 2026T23,162,96332,1303,617,7046,84646.6%
Sep 28, 2026T21,266,92520,4881,503,8155,07545.7%
Sep 21, 2026T21,510,98824,0621,092,6265,40958.0%
Sep 14, 2026T23,907,39237,2203,340,1837,19153.9%
Sep 7, 2026T21,818,07420,3342,418,5175,22942.9%
Aug 31, 2026T24,294,81839,0142,263,1218,05265.5%
Aug 24, 2026T24,693,43837,7391,946,7418,18170.7%
Aug 17, 2026T27,924,54964,7738,037,51215,76449.6%
Aug 10, 2026T22,943,10732,1001,924,3695,43560.5%
Aug 3, 2026T22,168,67233,3342,688,4205,80144.6%
Jul 27, 2026T23,142,72935,9182,297,6077,95557.8%
Jul 20, 2026T26,203,35167,8655,841,32318,28451.5%