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Comfort Systems USA Inc

FIX
Exchange
NYSE
Industry
Electrical Work
SEC CIK
0001035983

In the last 90 days, Comfort Systems USA Inc insiders filed 0 open-market purchases and 2 sales; 1,363 institutions reported holding it in 13F filings for Q2 2026, worth $64.6B in total; superinvestors Coatue Management and Markel Group hold 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
864.7K
Shares, settlement Oct 30, 2026
Change
+107.1K
+14.1% vs. Oct 15, 2026
Days to cover
1.26
Short interest ÷ average daily volume
Average daily volume
684.5K
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 536,221 sharesNov 15, 2024: 679,062 sharesNov 29, 2024: 652,618 sharesDec 13, 2024: 634,341 sharesDec 31, 2024: 744,739 sharesJan 15, 2025: 664,762 sharesJan 31, 2025: 723,039 sharesFeb 14, 2025: 741,352 sharesFeb 28, 2025: 1,027,070 sharesMar 14, 2025: 726,707 sharesMar 31, 2025: 862,079 sharesApr 15, 2025: 830,338 sharesApr 30, 2025: 775,494 sharesMay 15, 2025: 1,109,009 sharesMay 30, 2025: 592,614 sharesJun 13, 2025: 671,090 sharesJun 30, 2025: 759,630 sharesJul 15, 2025: 778,081 sharesJul 31, 2025: 690,283 sharesAug 15, 2025: 775,816 sharesAug 29, 2025: 690,937 sharesSep 15, 2025: 732,031 sharesSep 30, 2025: 665,142 sharesOct 15, 2025: 619,281 sharesOct 31, 2025: 558,433 sharesNov 14, 2025: 655,811 sharesNov 28, 2025: 734,974 sharesDec 15, 2025: 796,621 sharesDec 31, 2025: 775,068 sharesJan 15, 2026: 801,544 sharesJan 30, 2026: 732,808 sharesFeb 13, 2026: 646,648 sharesFeb 27, 2026: 652,846 sharesMar 13, 2026: 669,099 sharesMar 31, 2026: 621,334 sharesApr 15, 2026: 760,531 sharesApr 30, 2026: 760,735 sharesMay 15, 2026: 898,803 sharesMay 29, 2026: 825,373 sharesJun 15, 2026: 786,903 sharesJun 30, 2026: 746,501 sharesJul 15, 2026: 839,258 sharesJul 31, 2026: 695,921 sharesAug 14, 2026: 915,049 sharesAug 31, 2026: 910,248 sharesSep 15, 2026: 857,812 sharesSep 30, 2026: 849,979 sharesOct 15, 2026: 757,613 sharesOct 30, 2026: 864,696 shares
Short interest in FIX by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 2026864.7K+107.1K+14.1%684.5K1.26
Oct 15, 2026757.6K−92.4K−10.9%385.9K1.96
Sep 30, 2026850.0K−7.83K−0.9%325.7K2.61
Sep 15, 2026857.8K−52.4K−5.8%304.2K2.82
Aug 31, 2026910.2K−4.80K−0.5%412.1K2.21
Aug 14, 2026915.0K+219.1K+31.5%378.7K2.42
Jul 31, 2026695.9K−143.3K−17.1%621.5K1.12
Jul 15, 2026839.3K+92.8K+12.4%434.8K1.93
Jun 30, 2026746.5K−40.4K−5.1%617.7K1.21
Jun 15, 2026786.9K−38.5K−4.7%462.6K1.70
May 29, 2026825.4K−73.4K−8.2%433.1K1.91
May 15, 2026898.8K+138.1K+18.2%383.9K2.34
Apr 30, 2026760.7K+2040.0%450.8K1.69
Apr 15, 2026760.5K+139.2K+22.4%335.1K2.27
Mar 31, 2026621.3K−47.8K−7.1%454.7K1.37
Mar 13, 2026669.1K+16.3K+2.5%439.7K1.52
Feb 27, 2026652.8K+6.20K+1.0%566.5K1.15
Feb 13, 2026646.6K−86.2K−11.8%398.5K1.62
Jan 30, 2026732.8K−68.7K−8.6%356.5K2.06
Jan 15, 2026801.5K+26.5K+3.4%451.6K1.77
Dec 31, 2025775.1K−21.6K−2.7%1.05M1.00
Dec 15, 2025796.6K+61.6K+8.4%470.2K1.69
Nov 28, 2025735.0K+79.2K+12.1%709.9K1.04
Nov 14, 2025655.8K+97.4K+17.4%380.5K1.72
Oct 31, 2025558.4K−60.8K−9.8%477.9K1.17
Oct 15, 2025619.3K−45.9K−6.9%303.6K2.04
Sep 30, 2025665.1K−66.9K−9.1%400.1K1.66
Sep 15, 2025732.0K+41.1K+6.0%407.7K1.80
Aug 29, 2025690.9K−84.9K−10.9%367.5K1.88
Aug 15, 2025775.8K+85.5K+12.4%399.1K1.94
Jul 31, 2025690.3K−87.8K−11.3%490.0K1.41
Jul 15, 2025778.1K+18.5K+2.4%306.5K2.54
Jun 30, 2025759.6K+88.5K+13.2%385.8K1.97
Jun 13, 2025671.1K+78.5K+13.2%339.0K1.98
May 30, 2025592.6K−516.4K−46.6%312.9K1.89
May 15, 20251.11M+333.5K+43.0%398.7K2.78
Apr 30, 2025775.5K−54.8K−6.6%494.1K1.57
Apr 15, 2025830.3K−31.7K−3.7%558.2K1.49
Mar 31, 2025862.1K+135.4K+18.6%556.5K1.55
Mar 14, 2025726.7K−300.4K−29.2%619.0K1.17
Feb 28, 20251.03M+285.7K+38.5%776.6K1.32
Feb 14, 2025741.4K+18.3K+2.5%495.0K1.50
Jan 31, 2025723.0K+58.3K+8.8%590.7K1.22
Jan 15, 2025664.8K−80.0K−10.7%383.6K1.73
Dec 31, 2024744.7K+110.4K+17.4%302.0K2.47
Dec 13, 2024634.3K−18.3K−2.8%270.4K2.35
Nov 29, 2024652.6K−26.4K−3.9%351.6K1.86
Nov 15, 2024679.1K+142.8K+26.6%350.1K1.94
Oct 31, 2024536.2K+153.9K+40.3%398.4K1.35

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 FIX by settlement date
Settlement dateSharesPriceValue
Sep 24, 2026894$1,625.90$1.45M
Sep 23, 20261$1,625.13$1.63K
Sep 21, 202660$1,651.37$99.1K
Aug 17, 20267$1,774.06$12.4K
Aug 13, 2026121$1,738.82$210.4K
Jul 10, 20268$1,781.42$14.3K
Jul 9, 20265$1,684.94$8.42K
Jul 6, 202615,510$1,741.30$27.0M
Jul 2, 202644$1,865.15$82.1K
Jul 1, 20265$1,981.95$9.91K
Jun 29, 20266$1,854.23$11.1K
Jun 25, 2026615$1,954.47$1.20M
Jun 24, 2026102$1,908.07$194.6K
Jun 22, 202621$1,967.41$41.3K
Jun 16, 20262$1,952.02$3.90K
Jun 15, 202616,637$1,877.61$31.2M
Jun 12, 2026469$1,843.42$864.6K
Jun 9, 202661$1,852.03$113.0K
May 29, 202653$1,855.15$98.3K
May 15, 2026241$2,042.36$492.2K
May 14, 2026649$2,034.63$1.32M
Apr 27, 20262$1,726.12$3.45K
Apr 20, 202655$1,650.47$90.8K
Apr 17, 202619$1,605.97$30.5K
Apr 6, 20264$1,417.19$5.67K
Mar 25, 2026448$1,461.52$654.8K
Mar 24, 20269$1,408.25$12.7K
Mar 23, 20262$1,356.75$2.71K
Mar 19, 202657$1,423.00$81.1K
Feb 23, 20261,047$1,462.23$1.53M

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 FIX by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 10, 2026120,431125225,60053.4%
Nov 9, 2026140,6771,976266,59652.8%
Nov 6, 2026124,7771,873398,37631.3%
Nov 5, 2026210,7096,267710,89329.6%
Nov 4, 2026310,20911,422738,81042.0%
Nov 3, 2026121,567398213,08557.1%
Nov 2, 202695,379189203,15546.9%
Oct 30, 2026144,547424272,05153.1%
Oct 29, 2026113,81757229,09549.7%
Oct 28, 2026174,5310318,49754.8%
Oct 27, 2026116,13562216,98153.5%
Oct 26, 2026167,0568,589327,26951.0%
Oct 23, 2026273,48118,574627,57943.6%
Oct 22, 2026110,8311,961332,57033.3%
Oct 21, 202665,755552209,36931.4%
Oct 20, 202661,38034240,77425.5%
Oct 19, 202676,12784152,60349.9%
Oct 16, 202661,23548143,97842.5%
Oct 15, 2026115,96452349,54133.2%
Oct 14, 2026120,180105185,10664.9%
Oct 13, 202698,908134186,84352.9%
Oct 12, 202667,7229110,09161.5%
Oct 9, 202658,57290297,96059.8%
Oct 8, 202682,2442142,16457.9%
Oct 7, 2026110,1242185,26959.4%
Oct 6, 202689,5750211,63842.3%
Oct 5, 202649,480396102,55848.2%
Oct 2, 202658,40926111,91552.2%
Oct 1, 202673,22121126,29058.0%
Sep 30, 202665,36769100,77864.9%

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 FIX
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 19, 2026T11,079,40590,135581,80652,05765.0%
Oct 12, 2026T1718,13958,438333,61337,33568.3%
Oct 5, 2026T1482,10042,339338,28732,12358.8%
Sep 28, 2026T1385,25939,278358,56126,81651.8%
Sep 21, 2026T1335,46236,979302,73028,12152.6%
Sep 14, 2026T1372,33943,821378,02630,49149.6%
Sep 7, 2026T1285,75034,771297,32823,85549.0%
Aug 31, 2026T1451,03449,606378,77832,48554.4%
Aug 24, 2026T1499,13950,763399,53536,28655.5%
Aug 17, 2026T1537,62949,310469,95336,75453.4%
Aug 10, 2026T1441,38046,744472,51928,39048.3%
Aug 3, 2026T1553,13957,291470,10131,45554.1%