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TransMedics Group, Inc.

TMDX
Exchange
Nasdaq
Industry
Electromedical & Electrotherapeutic Apparatus
SEC CIK
0001756262

In the last 90 days, TransMedics Group, Inc. insiders filed 1 open-market purchase and 1 sale; 378 institutions reported holding it in 13F filings for Q2 2026, worth $2.31B in total; no superinvestor holds 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
8.88M
Shares, settlement Oct 30, 2026
Change
+108.5K
+1.2% vs. Oct 15, 2026
Days to cover
10.22
Short interest ÷ average daily volume
Average daily volume
869.1K
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 8,426,990 sharesNov 15, 2024: 8,975,940 sharesNov 29, 2024: 9,291,382 sharesDec 13, 2024: 8,639,718 sharesDec 31, 2024: 9,153,451 sharesJan 15, 2025: 8,990,700 sharesJan 31, 2025: 11,129,933 sharesFeb 14, 2025: 10,756,834 sharesFeb 28, 2025: 9,330,007 sharesMar 14, 2025: 9,551,242 sharesMar 31, 2025: 9,475,553 sharesApr 15, 2025: 8,782,313 sharesApr 30, 2025: 8,796,878 sharesMay 15, 2025: 8,104,743 sharesMay 30, 2025: 8,081,988 sharesJun 13, 2025: 7,860,937 sharesJun 30, 2025: 8,044,092 sharesJul 15, 2025: 7,995,364 sharesJul 31, 2025: 7,669,931 sharesAug 15, 2025: 7,841,719 sharesAug 29, 2025: 8,269,364 sharesSep 15, 2025: 8,394,299 sharesSep 30, 2025: 8,143,367 sharesOct 15, 2025: 7,971,237 sharesOct 31, 2025: 7,542,390 sharesNov 14, 2025: 6,860,927 sharesNov 28, 2025: 7,716,642 sharesDec 15, 2025: 6,996,469 sharesDec 31, 2025: 7,201,077 sharesJan 15, 2026: 7,280,097 sharesJan 30, 2026: 7,891,400 sharesFeb 13, 2026: 8,225,157 sharesFeb 27, 2026: 8,478,217 sharesMar 13, 2026: 8,330,878 sharesMar 31, 2026: 8,030,292 sharesApr 15, 2026: 7,606,337 sharesApr 30, 2026: 8,319,639 sharesMay 15, 2026: 8,178,039 sharesMay 29, 2026: 7,356,977 sharesJun 15, 2026: 7,680,998 sharesJun 30, 2026: 7,865,697 sharesJul 15, 2026: 7,715,332 sharesJul 31, 2026: 7,672,830 sharesAug 14, 2026: 7,910,244 sharesAug 31, 2026: 8,079,087 sharesSep 15, 2026: 7,977,125 sharesSep 30, 2026: 8,551,869 sharesOct 15, 2026: 8,769,040 sharesOct 30, 2026: 8,877,506 shares
Short interest in TMDX by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 20268.88M+108.5K+1.2%869.1K10.22
Oct 15, 20268.77M+217.2K+2.5%886.9K9.89
Sep 30, 20268.55M+574.7K+7.2%654.6K13.07
Sep 15, 20267.98M−102.0K−1.3%747.1K10.68
Aug 31, 20268.08M+168.8K+2.1%632.3K12.78
Aug 14, 20267.91M+237.4K+3.1%1.18M6.71
Jul 31, 20267.67M−42.5K−0.6%807.9K9.50
Jul 15, 20267.72M−150.4K−1.9%809.1K9.54
Jun 30, 20267.87M+184.7K+2.4%1.30M6.04
Jun 15, 20267.68M+324.0K+4.4%1.07M7.21
May 29, 20267.36M−821.1K−10.0%1.38M5.32
May 15, 20268.18M−141.6K−1.7%2.42M3.38
Apr 30, 20268.32M+713.3K+9.4%965.9K8.61
Apr 15, 20267.61M−424.0K−5.3%740.7K10.27
Mar 31, 20268.03M−300.6K−3.6%1.15M6.95
Mar 13, 20268.33M−147.3K−1.7%890.4K9.36
Feb 27, 20268.48M+253.1K+3.1%872.8K9.71
Feb 13, 20268.23M+333.8K+4.2%582.2K14.13
Jan 30, 20267.89M+611.3K+8.4%854.7K9.23
Jan 15, 20267.28M+79.0K+1.1%709.5K10.26
Dec 31, 20257.20M+204.6K+2.9%632.9K11.38
Dec 15, 20257.00M−720.2K−9.3%772.9K9.05
Nov 28, 20257.72M+855.7K+12.5%960.6K8.03
Nov 14, 20256.86M−681.5K−9.0%786.5K8.72
Oct 31, 20257.54M−428.8K−5.4%1.15M6.54
Oct 15, 20257.97M−172.1K−2.1%865.4K9.21
Sep 30, 20258.14M−250.9K−3.0%886.3K9.19
Sep 15, 20258.39M+124.9K+1.5%1.20M6.97
Aug 29, 20258.27M+427.6K+5.5%718.9K11.50
Aug 15, 20257.84M+171.8K+2.2%1.20M6.52
Jul 31, 20257.67M−325.4K−4.1%1.37M5.58
Jul 15, 20258.00M−48.7K−0.6%905.0K8.83
Jun 30, 20258.04M+183.2K+2.3%918.1K8.76
Jun 13, 20257.86M−221.1K−2.7%777.7K10.11
May 30, 20258.08M−22.8K−0.3%692.3K11.67
May 15, 20258.10M−692.1K−7.9%1.54M5.28
Apr 30, 20258.80M+14.6K+0.2%1.03M8.54
Apr 15, 20258.78M−693.2K−7.3%1.32M6.65
Mar 31, 20259.48M−75.7K−0.8%757.9K12.50
Mar 14, 20259.55M+221.2K+2.4%1.08M8.88
Feb 28, 20259.33M−1.43M−13.3%1.68M5.54
Feb 14, 202510.8M−373.1K−3.4%1.24M8.66
Jan 31, 202511.1M+2.14M+23.8%1.80M6.19
Jan 15, 20258.99M−162.8K−1.8%3.95M2.28
Dec 31, 20249.15M+513.7K+6.0%1.31M7.00
Dec 13, 20248.64M−651.7K−7.0%2.06M4.19
Nov 29, 20249.29M+315.4K+3.5%1.73M5.37
Nov 15, 20248.98M+549.0K+6.5%1.56M5.77
Oct 31, 20248.43M+1.99M+30.9%2.68M3.14

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 TMDX by settlement date
Settlement dateSharesPriceValue
Oct 9, 20264$79.00$316
Oct 2, 2026343$78.64$27.0K
Sep 22, 202646,847$87.29$4.09M
Sep 21, 2026291,098$86.42$25.2M
Sep 11, 202631,021$85.04$2.64M
Sep 8, 20261,736$89.98$156.2K
Sep 4, 20261$86.98$86.98
Sep 2, 202624$82.24$1.97K
Aug 26, 20265$93.60$468
Aug 25, 202698,071$93.60$9.18M
Aug 24, 20264,431$94.77$419.9K
Aug 17, 2026109$88.58$9.66K
Aug 14, 202638$89.64$3.41K
Aug 13, 202639,375$87.02$3.43M
Aug 11, 20262,640$88.41$233.4K
Aug 7, 2026938$80.21$75.2K
Jul 29, 20261,379$76.29$105.2K
Jul 28, 202658,496$74.28$4.35M
Jul 27, 202661,353$72.26$4.43M
Jul 22, 2026192$74.29$14.3K
Jul 20, 20266,827$73.98$505.1K
Jul 16, 202612$75.38$904.56
Jul 14, 20261,096$75.74$83.0K
Jul 13, 2026847$71.23$60.3K
Jul 7, 202615$71.23$1.07K
Jun 26, 2026206$77.75$16.0K
Jun 25, 2026292$77.62$22.7K
Jun 24, 2026161$73.83$11.9K
Jun 23, 2026269$75.51$20.3K
Jun 22, 2026200$78.79$15.8K

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 TMDX by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 12, 2026280,4853,460503,97355.7%
Nov 11, 2026228,788173417,95654.7%
Nov 10, 2026462,6533,862800,37457.8%
Nov 9, 2026414,118140,926967,16642.8%
Nov 6, 2026646,7261,9381,187,08254.5%
Nov 5, 2026279,525127717,91738.9%
Nov 4, 2026357,1764,665656,13454.4%
Nov 3, 2026154,4232280,01755.1%
Nov 2, 2026154,1590261,33959.0%
Oct 30, 2026180,2783,210358,57650.3%
Oct 29, 2026225,1930425,37952.9%
Oct 28, 2026245,4710560,17343.8%
Oct 27, 2026225,763113426,18853.0%
Oct 26, 2026236,8096,103446,64153.0%
Oct 23, 2026183,2472,329308,42259.4%
Oct 22, 2026130,8650268,62848.7%
Oct 21, 202692,66776304,27730.5%
Oct 20, 2026256,97927,179494,39452.0%
Oct 19, 2026166,1030287,12057.9%
Oct 16, 2026335,668291508,71866.0%
Oct 15, 2026255,183850464,59254.9%
Oct 14, 2026214,923413422,52950.9%
Oct 13, 2026146,638101309,08947.4%
Oct 12, 202676,626100180,01042.6%
Oct 9, 2026174,862464317,09655.1%
Oct 8, 2026242,5814400,92460.5%
Oct 7, 2026212,76954,525392,10754.3%
Oct 6, 202684,499138263,77832.0%
Oct 5, 2026201,5651,001369,37954.6%
Oct 2, 2026279,15961567,76049.2%

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 TMDX
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 5, 2026T21,087,95228,752763,11112,82058.8%
Sep 28, 2026T21,026,86630,110672,99213,70360.4%
Sep 21, 2026T21,117,10432,099430,17110,68672.2%
Sep 14, 2026T21,142,55933,100748,25512,17560.4%
Sep 7, 2026T2847,28330,075662,71510,84856.1%
Aug 31, 2026T2998,83433,419649,35011,88160.6%
Aug 24, 2026T2719,06427,742531,30510,86657.5%
Aug 17, 2026T2902,23232,617504,96112,86864.1%
Aug 10, 2026T21,135,66736,973962,29414,95954.1%
Aug 3, 2026T22,186,29653,0701,218,85423,08764.2%
Jul 27, 2026T21,104,60634,645611,47311,93464.4%
Jul 20, 2026T21,224,69630,464812,58212,36060.1%