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Arch Capital Group Ltd.

ACGLO
Exchange
Nasdaq
Industry
Fire, Marine & Casualty Insurance
SEC CIK
0000947484

In the last 90 days, Arch Capital Group Ltd. insiders filed 0 open-market purchases and 2 sales; 2 institutions reported holding it in 13F filings for Q2 2026, worth $28.9K in total; no superinvestor holds it.

Other share classesACGLACGLN

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
88.7K
Shares, settlement Oct 30, 2026
Change
−57.7K
−39.4% vs. Oct 15, 2026
Days to cover
2.23
Short interest ÷ average daily volume
Average daily volume
39.8K
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 13,268 sharesNov 15, 2024: 5,404 sharesNov 29, 2024: 1,961 sharesDec 13, 2024: 22,562 sharesDec 31, 2024: 23,243 sharesJan 15, 2025: 17,409 sharesJan 31, 2025: 25,829 sharesFeb 14, 2025: 18,156 sharesFeb 28, 2025: 14,967 sharesMar 14, 2025: 21,404 sharesMar 31, 2025: 45,422 sharesApr 15, 2025: 96,446 sharesApr 30, 2025: 65,399 sharesMay 15, 2025: 68,751 sharesMay 30, 2025: 59,963 sharesJun 13, 2025: 65,750 sharesJun 30, 2025: 81,464 sharesJul 15, 2025: 84,362 sharesJul 31, 2025: 103,297 sharesAug 15, 2025: 75,419 sharesAug 29, 2025: 96,699 sharesSep 15, 2025: 98,671 sharesSep 30, 2025: 57,833 sharesOct 15, 2025: 62,892 sharesOct 31, 2025: 59,304 sharesNov 14, 2025: 24,132 sharesNov 28, 2025: 22,719 sharesDec 15, 2025: 40,366 sharesDec 31, 2025: 11,048 sharesJan 15, 2026: 16,491 sharesJan 30, 2026: 17,346 sharesFeb 13, 2026: 22,729 sharesFeb 27, 2026: 31,851 sharesMar 13, 2026: 23,588 sharesMar 31, 2026: 23,140 sharesApr 15, 2026: 14,986 sharesApr 30, 2026: 12,196 sharesMay 15, 2026: 28,778 sharesMay 29, 2026: 19,754 sharesJun 15, 2026: 8,496 sharesJun 30, 2026: 24,748 sharesJul 15, 2026: 34,220 sharesJul 31, 2026: 64,808 sharesAug 14, 2026: 46,190 sharesAug 31, 2026: 44,742 sharesSep 15, 2026: 33,019 sharesSep 30, 2026: 138,946 sharesOct 15, 2026: 146,421 sharesOct 30, 2026: 88,738 shares
Short interest in ACGLO by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 202688.7K−57.7K−39.4%39.8K2.23
Oct 15, 2026146.4K+7.47K+5.4%37.2K3.94
Sep 30, 2026138.9K+105.9K+320.8%51.3K2.71
Sep 15, 202633.0K−11.7K−26.2%34.3K1.00
Aug 31, 202644.7K−1.45K−3.1%23.9K1.87
Aug 14, 202646.2K−18.6K−28.7%21.1K2.19
Jul 31, 202664.8K+30.6K+89.4%31.7K2.04
Jul 15, 202634.2K+9.47K+38.3%40.0K1.00
Jun 30, 202624.7K+16.3K+191.3%50.3K1.00
Jun 15, 20268.50K−11.3K−57.0%24.4K1.00
May 29, 202619.8K−9.02K−31.4%19.1K1.03
May 15, 202628.8K+16.6K+136.0%15.6K1.85
Apr 30, 202612.2K−2.79K−18.6%17.3K1.00
Apr 15, 202615.0K−8.15K−35.2%29.2K1.00
Mar 31, 202623.1K−448−1.9%28.8K1.00
Mar 13, 202623.6K−8.26K−25.9%17.6K1.34
Feb 27, 202631.9K+9.12K+40.1%21.0K1.52
Feb 13, 202622.7K+5.38K+31.0%21.1K1.08
Jan 30, 202617.3K+855+5.2%29.7K1.00
Jan 15, 202616.5K+5.44K+49.3%26.9K1.00
Dec 31, 202511.0K−29.3K−72.6%40.0K1.00
Dec 15, 202540.4K+17.6K+77.7%25.8K1.56
Nov 28, 202522.7K−1.41K−5.9%19.9K1.14
Nov 14, 202524.1K−35.2K−59.3%16.5K1.46
Oct 31, 202559.3K−3.59K−5.7%17.2K3.45
Oct 15, 202562.9K+5.06K+8.8%11.4K5.50
Sep 30, 202557.8K−40.8K−41.4%13.9K4.15
Sep 15, 202598.7K+1.97K+2.0%18.5K5.33
Aug 29, 202596.7K+21.3K+28.2%19.0K5.09
Aug 15, 202575.4K−27.9K−27.0%15.9K4.75
Jul 31, 2025103.3K+18.9K+22.4%19.7K5.25
Jul 15, 202584.4K+2.90K+3.6%19.3K4.37
Jun 30, 202581.5K+15.7K+23.9%27.0K3.02
Jun 13, 202565.8K+5.79K+9.7%17.6K3.74
May 30, 202560.0K−8.79K−12.8%20.1K2.99
May 15, 202568.8K+3.35K+5.1%19.0K3.62
Apr 30, 202565.4K−31.0K−32.2%25.6K2.56
Apr 15, 202596.4K+51.0K+112.3%34.5K2.79
Mar 31, 202545.4K+24.0K+112.2%34.9K1.30
Mar 14, 202521.4K+6.44K+43.0%17.8K1.20
Feb 28, 202515.0K−3.19K−17.6%17.7K1.00
Feb 14, 202518.2K−7.67K−29.7%16.4K1.11
Jan 31, 202525.8K+8.42K+48.4%27.4K1.00
Jan 15, 202517.4K−5.83K−25.1%28.5K1.00
Dec 31, 202423.2K+681+3.0%62.4K1.00
Dec 13, 202422.6K+20.6K+1,050.5%29.5K1.00
Nov 29, 20241.96K−3.44K−63.7%20.6K1.00
Nov 15, 20245.40K−7.86K−59.3%15.8K1.00
Oct 31, 202413.3K+8.15K+159.4%20.9K1.00

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 ACGLO by settlement date
Settlement dateSharesPriceValue
Oct 13, 20266,830$18.27$124.8K
Oct 9, 2026729$18.20$13.3K
Oct 5, 202624$18.48$443.52
Oct 1, 2026148$18.13$2.68K
Sep 30, 2026210$18.52$3.89K
Sep 29, 2026117$18.56$2.17K
Sep 28, 20269,067$18.83$170.7K
Sep 24, 20263,780$18.76$70.9K
Sep 23, 2026789$18.79$14.8K
Sep 22, 2026643$18.71$12.0K
Sep 21, 20267,710$18.34$141.4K
Sep 10, 202678$18.81$1.47K
Sep 3, 2026449$18.94$8.50K
Sep 1, 2026231$18.95$4.38K
Aug 13, 2026292$19.31$5.64K
Aug 7, 20261,247$19.32$24.1K
Jul 15, 20262,917$19.30$56.3K
Jul 14, 20262,026$19.00$38.5K
Jul 13, 2026494$18.95$9.36K
Jul 1, 20262,066$19.13$39.5K
Jun 30, 20262,486$19.12$47.5K
Jun 16, 20261,351$19.21$26.0K
Apr 29, 202678$20.41$1.59K
Apr 1, 202667$19.48$1.31K
Mar 18, 202620$20.22$404.4
Mar 12, 2026215$20.49$4.41K
Mar 11, 202693$20.54$1.91K
Feb 18, 20261,279$21.08$27.0K
Jan 23, 20264$21.04$84.16
Dec 17, 20251,299$20.72$26.9K

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 ACGLO by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 13, 20265,695023,97323.8%
Nov 12, 20265,8522121,68927.0%
Nov 11, 20265,463415,32435.6%
Nov 10, 202618,742029,14964.3%
Nov 9, 202612,7652824,89151.3%
Nov 6, 20264,54435014,86630.6%
Nov 5, 20265,232019,46526.9%
Nov 4, 20267,18251721,55133.3%
Nov 3, 202610,932023,10647.3%
Nov 2, 202613,45872131,88142.2%
Oct 30, 202621,032033,37363.0%
Oct 29, 20266,66944923,21828.7%
Oct 28, 202616,41510840,87240.2%
Oct 27, 202613,54347327,44049.4%
Oct 26, 202612,482032,05938.9%
Oct 23, 20264,658015,64029.8%
Oct 22, 202613,542022,15861.1%
Oct 21, 20264,099015,79925.9%
Oct 20, 20266,436015,34841.9%
Oct 19, 202613,518023,29858.0%
Oct 16, 202640,769049,41382.5%
Oct 15, 202610,25932721,03448.8%
Oct 14, 202616,081026,04761.7%
Oct 13, 202613,880019,70070.5%
Oct 12, 202617,087023,95471.3%
Oct 9, 20265,230013,00340.2%
Oct 8, 202618,40850039,46346.6%
Oct 7, 202630,725041,09474.8%
Oct 6, 20269,261020,31145.6%
Oct 5, 202611,540022,39451.5%

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 ACGLO
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 5, 2026T25,36598131,2038773.9%
Sep 28, 2026T26,653466112,9057355.6%
Sep 21, 2026T219,999211132,94189613.1%
Sep 14, 2026T226,808331171,69091713.5%
Sep 7, 2026T25,20813565,5487737.4%
Aug 31, 2026T29,76725676,95758911.3%
Aug 24, 2026T26,72514479,3116147.8%
Aug 17, 2026T22,8687464,2416804.3%
Aug 10, 2026T22,9887854,1696965.2%
Aug 3, 2026T26,5518870,6057678.5%
Jul 27, 2026T28,87326480,4336209.9%
Jul 20, 2026T29,112185119,3599147.1%