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FibroBiologics, Inc.

FBLG
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0001958777

No open-market purchases or sales by FibroBiologics, Inc. insiders were filed in the last 90 days; 17 institutions reported holding it in 13F filings for Q2 2026, worth $269.7K 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
334.1K
Shares, settlement Oct 30, 2026
Change
+3.57K
+1.1% vs. Oct 15, 2026
Days to cover
3.12
Short interest ÷ average daily volume
Average daily volume
107.0K
Shares, as reported by FINRA
Short interest by settlement date
Oct 31, 2024: 2,360,164 sharesNov 15, 2024: 2,529,228 sharesNov 29, 2024: 2,699,732 sharesDec 13, 2024: 2,496,704 sharesDec 31, 2024: 2,473,554 sharesJan 15, 2025: 2,501,272 sharesJan 31, 2025: 1,804,615 sharesFeb 14, 2025: 1,950,839 sharesFeb 28, 2025: 2,045,107 sharesMar 14, 2025: 2,213,284 sharesMar 31, 2025: 2,251,750 sharesApr 15, 2025: 1,527,926 sharesApr 30, 2025: 1,589,746 sharesMay 15, 2025: 1,567,091 sharesMay 30, 2025: 1,249,313 sharesJun 13, 2025: 1,347,117 sharesJun 30, 2025: 751,926 sharesJul 15, 2025: 730,581 sharesJul 31, 2025: 1,039,248 sharesAug 15, 2025: 1,098,551 sharesAug 29, 2025: 917,549 sharesSep 15, 2025: 970,560 sharesSep 30, 2025: 965,853 sharesOct 15, 2025: 2,029,942 sharesOct 31, 2025: 1,811,524 sharesNov 14, 2025: 1,410,801 sharesNov 28, 2025: 1,389,641 sharesDec 15, 2025: 795,335 sharesDec 31, 2025: 907,076 sharesJan 15, 2026: 372,855 sharesJan 30, 2026: 851,743 sharesFeb 13, 2026: 630,020 sharesFeb 27, 2026: 671,279 sharesMar 13, 2026: 873,527 sharesMar 31, 2026: 209,586 sharesApr 15, 2026: 99,974 sharesApr 30, 2026: 118,414 sharesMay 15, 2026: 237,640 sharesMay 29, 2026: 135,591 sharesJun 15, 2026: 137,027 sharesJun 30, 2026: 135,794 sharesJul 15, 2026: 70,837 sharesJul 31, 2026: 115,200 sharesAug 14, 2026: 141,714 sharesAug 31, 2026: 413,742 sharesSep 15, 2026: 661,912 sharesSep 30, 2026: 522,114 sharesOct 15, 2026: 330,551 sharesOct 30, 2026: 334,123 shares
Short interest in FBLG by settlement date
Settlement dateShort interestChangeChange %Avg. daily volumeDays to cover
Oct 30, 2026334.1K+3.57K+1.1%107.0K3.12
Oct 15, 2026330.6K−191.6K−36.7%140.5K2.35
Sep 30, 2026522.1K−139.8K−21.1%136.5K3.82
Sep 15, 2026661.9K+248.2K+60.0%357.9K1.85
Aug 31, 2026413.7K+272.0K+192.0%295.0K1.40
Aug 14, 2026141.7K+26.5K+23.0%248.4K1.00
Jul 31, 2026115.2K+44.4K+62.6%90.9K1.27
Jul 15, 202670.8K−65.0K−47.8%59.6K1.19
Jun 30, 2026135.8K−1.23K−0.9%260.5K1.00
Jun 15, 2026137.0K+1.44K+1.1%148.4K1.00
May 29, 2026135.6K−102.0K−42.9%99.8K1.36
May 15, 2026237.6K+119.2K+100.7%563.6K1.00
Apr 30, 2026118.4K+18.4K+18.4%184.8K1.00
Apr 15, 2026100.0K−109.6K−52.3%744.4K1.00
Mar 31, 2026Split209.6K−663.9K−76.0%828.2K1.00
Mar 13, 2026873.5K+202.2K+30.1%1.50M1.00
Feb 27, 2026671.3K+41.3K+6.6%585.3K1.15
Feb 13, 2026630.0K−221.7K−26.0%1.23M1.00
Jan 30, 2026851.7K+478.9K+128.4%689.4K1.24
Jan 15, 2026372.9K−534.2K−58.9%2.49M1.00
Dec 31, 2025907.1K+111.7K+14.1%3.54M1.00
Dec 15, 2025795.3K−594.3K−42.8%1.96M1.00
Nov 28, 20251.39M−21.2K−1.5%1.83M1.00
Nov 14, 20251.41M−400.7K−22.1%1.04M1.36
Oct 31, 20251.81M−218.4K−10.8%983.7K1.84
Oct 15, 20252.03M+1.06M+110.2%1.23M1.64
Sep 30, 2025965.9K−4.71K−0.5%881.6K1.10
Sep 15, 2025970.6K+53.0K+5.8%456.0K2.13
Aug 29, 2025917.5K−181.0K−16.5%419.7K2.19
Aug 15, 20251.10M+59.3K+5.7%482.7K2.28
Jul 31, 20251.04M+308.7K+42.3%498.4K2.09
Jul 15, 2025730.6K−21.3K−2.8%450.4K1.62
Jun 30, 2025751.9K−595.2K−44.2%674.5K1.11
Jun 13, 20251.35M+97.8K+7.8%323.1K4.17
May 30, 20251.25M−317.8K−20.3%181.6K6.88
May 15, 20251.57M−22.7K−1.4%189.7K8.26
Apr 30, 20251.59M+61.8K+4.1%299.0K5.32
Apr 15, 20251.53M−723.8K−32.1%213.2K7.17
Mar 31, 20252.25M+38.5K+1.7%114.6K19.65
Mar 14, 20252.21M+168.2K+8.2%175.7K12.60
Feb 28, 20252.05M+94.3K+4.8%271.0K7.55
Feb 14, 20251.95M+146.2K+8.1%810.0K2.41
Jan 31, 20251.80M−696.7K−27.9%240.0K7.52
Jan 15, 20252.50M+27.7K+1.1%123.6K20.23
Dec 31, 20242.47M−23.1K−0.9%146.0K16.94
Dec 13, 20242.50M−203.0K−7.5%115.4K21.63
Nov 29, 20242.70M+170.5K+6.7%156.8K17.22
Nov 15, 20242.53M+169.1K+7.2%239.3K10.57
Oct 31, 20242.36M+8.58K+0.4%160.4K14.71

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 FBLG by settlement date
Settlement dateSharesPriceValue
Oct 13, 20263,783$1.00$3.78K
Sep 30, 2026778$1.31$1.02K
Sep 28, 2026395$1.39$549.05
Sep 25, 2026339$1.36$461.04
Sep 24, 20268,049$1.33$10.7K
Sep 23, 20261$1.34$1.34
Sep 10, 20261,650$1.76$2.90K
Sep 9, 20261,740$1.71$2.98K
Sep 8, 2026130$1.81$235.3
Sep 4, 202611,462$1.76$20.2K
Sep 3, 20261,102$1.95$2.15K
Sep 2, 202629,056$2.11$61.3K
Sep 1, 20263,201$1.72$5.51K
Aug 31, 2026427$1.44$614.88
Aug 26, 2026400$1.40$560
Aug 24, 202619,845$1.44$28.6K
Aug 20, 2026383$1.19$455.77
Aug 19, 202622,249$1.14$25.4K
Aug 17, 20263,822$1.07$4.09K
Aug 14, 20262$1.15$2.3
Aug 13, 20262$1.11$2.22
Aug 6, 20262,012$0.87$1.75K
Aug 5, 2026342$0.82$280.44
Aug 4, 20264,324$0.79$3.42K
Aug 3, 20261,549$0.70$1.08K
Jul 31, 2026338$0.72$243.36
Jul 30, 2026396$0.65$257.4
Jul 29, 2026364$0.64$232.96
Jul 24, 2026942$0.74$697.08
Jul 23, 20262,114$0.74$1.56K

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 FBLG by trade date
Trade dateShort volumeShort exemptOff-exchange volumeShort volume ratio
Nov 11, 202630,83570037,99881.1%
Nov 10, 202614,845031,21847.6%
Nov 9, 202634,214044,63676.7%
Nov 6, 202613,363018,73071.3%
Nov 5, 202618,024058,92630.6%
Nov 4, 20265,161036,03914.3%
Nov 3, 20268,569014,17060.5%
Nov 2, 202614,896028,09553.0%
Oct 30, 20266,756014,30247.2%
Oct 29, 20262,23309,06324.6%
Oct 28, 20264,956014,41834.4%
Oct 27, 20263,62405,65864.1%
Oct 26, 202655,142090,62860.8%
Oct 23, 20262,754016,96116.2%
Oct 22, 202692,3950222,14641.6%
Oct 21, 20269,391049,71218.9%
Oct 20, 202645,179059,71075.7%
Oct 19, 202641,511068,59460.5%
Oct 16, 20264,087010,12440.4%
Oct 15, 202641,601078,62852.9%
Oct 14, 202617,0105049,01334.7%
Oct 13, 202612,0341,24232,78036.7%
Oct 12, 202611,2362,48076,98514.6%
Oct 9, 202611,189055,38520.2%
Oct 8, 202615,636027,18057.5%
Oct 7, 202627,3370129,81021.1%
Oct 6, 202637,2200118,66031.4%
Oct 5, 202618,155055,18332.9%
Oct 2, 202643,7909,82887,14750.2%
Oct 1, 202635,4703,75263,37756.0%

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 FBLG
Week ofTierATS sharesATS tradesOther OTC sharesOther OTC tradesATS share
Oct 5, 2026T223,244226390,5389315.6%
Sep 28, 2026T248,994527363,0641,13011.9%
Sep 21, 2026T225,529330289,6889168.1%
Sep 14, 2026T227,972574369,1959557.0%
Sep 7, 2026T220,943448304,7687686.4%
Aug 31, 2026T2178,1932,9021,681,5095,5509.6%
Aug 24, 2026T245,324534437,3801,5579.4%
Aug 17, 2026T288,399818943,8002,5158.6%
Aug 10, 2026T258,826704624,5461,6518.6%
Aug 3, 2026T242,071334874,8432,0964.6%
Jul 27, 2026T215,66798350,0271,0364.3%
Jul 20, 2026T210,897463211,6659804.9%