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Mirum Pharmaceuticals, Inc.

MIRM
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0001759425

In the last 90 days, Mirum Pharmaceuticals, Inc. insiders filed 0 open-market purchases and 5 sales; 328 institutions reported holding it in 13F filings for Q2 2026, worth $8.36B 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
6.52M
Shares, settlement Oct 30, 2026
Change
−139.3K
−2.1% vs. Oct 15, 2026
Days to cover
11.84
Short interest ÷ average daily volume
Average daily volume
551.1K
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 6,845,267 sharesNov 15, 2024: 6,973,282 sharesNov 29, 2024: 6,717,759 sharesDec 13, 2024: 6,843,628 sharesDec 31, 2024: 6,430,289 sharesJan 15, 2025: 6,649,342 sharesJan 31, 2025: 6,573,423 sharesFeb 14, 2025: 6,608,635 sharesFeb 28, 2025: 6,626,034 sharesMar 14, 2025: 6,282,518 sharesMar 31, 2025: 6,578,301 sharesApr 15, 2025: 6,279,087 sharesApr 30, 2025: 6,225,486 sharesMay 15, 2025: 6,287,171 sharesMay 30, 2025: 6,059,537 sharesJun 13, 2025: 6,218,308 sharesJun 30, 2025: 6,512,657 sharesJul 15, 2025: 6,580,855 sharesJul 31, 2025: 6,634,186 sharesAug 15, 2025: 6,926,980 sharesAug 29, 2025: 6,861,339 sharesSep 15, 2025: 7,501,510 sharesSep 30, 2025: 7,365,570 sharesOct 15, 2025: 7,389,080 sharesOct 31, 2025: 7,027,185 sharesNov 14, 2025: 7,661,323 sharesNov 28, 2025: 7,464,991 sharesDec 15, 2025: 7,374,120 sharesDec 31, 2025: 8,363,319 sharesJan 15, 2026: 7,589,951 sharesJan 30, 2026: 7,795,041 sharesFeb 13, 2026: 8,040,628 sharesFeb 27, 2026: 7,623,019 sharesMar 13, 2026: 7,460,121 sharesMar 31, 2026: 8,050,414 sharesApr 15, 2026: 8,213,781 sharesApr 30, 2026: 8,413,814 sharesMay 15, 2026: 8,196,668 sharesMay 29, 2026: 6,561,290 sharesJun 15, 2026: 6,909,142 sharesJun 30, 2026: 7,483,286 sharesJul 15, 2026: 7,272,892 sharesJul 31, 2026: 6,823,706 sharesAug 14, 2026: 6,489,383 sharesAug 31, 2026: 6,171,979 sharesSep 15, 2026: 6,281,413 sharesSep 30, 2026: 6,985,385 sharesOct 15, 2026: 6,663,045 sharesOct 30, 2026: 6,523,716 shares
Short interest in MIRM by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 20266.52M−139.3K−2.1%551.1K11.84
Oct 15, 20266.66M−322.3K−4.6%912.8K7.30
Sep 30, 20266.99M+704.0K+11.2%910.9K7.67
Sep 15, 20266.28M+109.4K+1.8%523.9K11.99
Aug 31, 20266.17M−317.4K−4.9%467.2K13.21
Aug 14, 20266.49M−334.3K−4.9%892.9K7.27
Jul 31, 20266.82M−449.2K−6.2%566.3K12.05
Jul 15, 20267.27M−210.4K−2.8%686.5K10.59
Jun 30, 20267.48M+574.1K+8.3%1.49M5.02
Jun 15, 20266.91M+347.9K+5.3%614.9K11.24
May 29, 20266.56M−1.64M−20.0%828.3K7.92
May 15, 20268.20M−217.1K−2.6%1.70M4.83
Apr 30, 20268.41M+200.0K+2.4%573.7K14.67
Apr 15, 20268.21M+163.4K+2.0%655.2K12.54
Mar 31, 20268.05M+590.3K+7.9%1.18M6.84
Mar 13, 20267.46M−162.9K−2.1%823.6K9.06
Feb 27, 20267.62M−417.6K−5.2%781.9K9.75
Feb 13, 20268.04M+245.6K+3.2%631.8K12.73
Jan 30, 20267.80M+205.1K+2.7%816.0K9.55
Jan 15, 20267.59M−773.4K−9.3%897.5K8.46
Dec 31, 20258.36M+989.2K+13.4%920.5K9.09
Dec 15, 20257.37M−90.9K−1.2%691.3K10.67
Nov 28, 20257.46M−196.3K−2.6%410.3K18.19
Nov 14, 20257.66M+634.1K+9.0%772.7K9.91
Oct 31, 20257.03M−361.9K−4.9%419.5K16.75
Oct 15, 20257.39M+23.5K+0.3%738.9K10.00
Sep 30, 20257.37M−135.9K−1.8%884.5K8.33
Sep 15, 20257.50M+640.2K+9.3%530.8K14.13
Aug 29, 20256.86M−65.6K−1.0%903.0K7.60
Aug 15, 20256.93M+292.8K+4.4%952.2K7.27
Jul 31, 20256.63M+53.3K+0.8%308.4K21.51
Jul 15, 20256.58M+68.2K+1.1%467.4K14.08
Jun 30, 20256.51M+294.3K+4.7%474.3K13.73
Jun 13, 20256.22M+158.8K+2.6%441.2K14.09
May 30, 20256.06M−227.6K−3.6%304.5K19.90
May 15, 20256.29M+61.7K+1.0%476.4K13.20
Apr 30, 20256.23M−53.6K−0.9%358.8K17.35
Apr 15, 20256.28M−299.2K−4.6%511.9K12.27
Mar 31, 20256.58M+295.8K+4.7%438.0K15.02
Mar 14, 20256.28M−343.5K−5.2%536.5K11.71
Feb 28, 20256.63M+17.4K+0.3%666.0K9.95
Feb 14, 20256.61M+35.2K+0.5%449.8K14.69
Jan 31, 20256.57M−75.9K−1.1%531.3K12.37
Jan 15, 20256.65M+219.1K+3.4%492.6K13.50
Dec 31, 20246.43M−413.3K−6.0%375.5K17.12
Dec 13, 20246.84M+125.9K+1.9%377.5K18.13
Nov 29, 20246.72M−255.5K−3.7%380.9K17.64
Nov 15, 20246.97M+128.0K+1.9%459.8K15.16
Oct 31, 20246.85M−155.4K−2.2%270.6K25.30

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 MIRM by settlement date
Settlement dateSharesPriceValue
Oct 9, 20262$81.35$162.7
Oct 8, 2026748$80.64$60.3K
Oct 7, 2026116$79.25$9.19K
Sep 30, 202626,924$87.54$2.36M
Sep 23, 20268,767$91.39$801.2K
Sep 22, 202644,759$92.00$4.12M
Sep 21, 202632,778$91.83$3.01M
Sep 18, 202637,524$98.82$3.71M
Sep 10, 202627$98.30$2.65K
Sep 9, 202617,137$99.53$1.71M
Aug 24, 202630$96.31$2.89K
Aug 18, 20262$99.83$199.66
Jul 31, 202672$112.59$8.11K
Jul 28, 2026226,091$114.20$25.8M
Jul 27, 2026228,372$113.03$25.8M
Jul 24, 2026241,590$114.36$27.6M
Jul 20, 202658$118.86$6.89K
Jul 16, 202621$121.00$2.54K
Jul 9, 2026899$128.57$115.6K
Jul 7, 20262$121.91$243.82
Jul 1, 20268$117.07$936.56
Jun 30, 20266,236$123.00$767.0K
Jun 29, 202615,591$123.77$1.93M
Jun 16, 2026140$101.00$14.1K
Jun 12, 20268,012$99.54$797.5K
Jun 8, 20268,329$93.48$778.6K
Jun 3, 202670$92.17$6.45K
Jun 2, 202653$96.33$5.11K
May 27, 202650$98.90$4.95K
May 26, 2026298$98.62$29.4K

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 MIRM by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 10, 2026129,3460290,93944.5%
Nov 9, 2026109,115363272,86240.0%
Nov 6, 202685,2456,475343,38324.8%
Nov 5, 2026172,0052,866353,38448.7%
Nov 4, 2026280,16724,176490,06457.2%
Nov 3, 2026160,3041,466292,77354.8%
Nov 2, 2026143,197116216,71466.1%
Oct 30, 2026115,5751328,82735.1%
Oct 29, 202686,162589209,26441.2%
Oct 28, 2026108,82852206,46652.7%
Oct 27, 202685,6540268,62131.9%
Oct 26, 202679,871145141,47156.5%
Oct 23, 2026240,563116,014300,48580.1%
Oct 22, 202678,617174115,65568.0%
Oct 21, 2026194,0960271,65471.4%
Oct 20, 2026185,549620254,04973.0%
Oct 19, 202661,75865127,87148.3%
Oct 16, 202677,1350162,33147.5%
Oct 15, 2026104,86111258,05540.6%
Oct 14, 2026101,04847437,73823.1%
Oct 13, 2026121,843631316,95838.4%
Oct 12, 2026286,2520508,85556.3%
Oct 9, 2026350,8353,000526,85566.6%
Oct 8, 2026114,964220250,53845.9%
Oct 7, 2026116,0105,833384,20930.2%
Oct 6, 2026107,498184466,77423.0%
Oct 5, 2026110,3381,410416,74626.5%
Oct 2, 2026264,85486483,82854.7%
Oct 1, 202694,0113,868270,93434.7%
Sep 30, 2026243,436484416,69558.4%

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 MIRM
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 5, 2026T21,541,29034,275715,1837,48168.3%
Sep 28, 2026T21,366,01728,435844,6747,66461.8%
Sep 21, 2026T21,033,17028,607574,3277,65964.3%
Sep 14, 2026T2918,43027,3761,249,2446,03042.4%
Sep 7, 2026T2701,34520,786288,3974,13570.9%
Aug 31, 2026T2523,71223,801358,1574,61059.4%
Aug 24, 2026T2680,02820,357301,1623,91869.3%
Aug 17, 2026T2769,06826,105371,1335,07467.5%
Aug 10, 2026T21,047,11132,447612,4515,30163.1%
Aug 3, 2026T21,908,32639,279665,4307,16674.1%
Jul 27, 2026T2779,59225,310328,2144,67570.4%
Jul 20, 2026T2897,50727,138576,7174,46760.9%