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LB Pharmaceuticals LBRX

US equityMarket cap rank #3171
$34.16 −$0.10 (-0.29%)
Pre-market · Oct 8, 7:30 am ET · After hours $34.16 0.00%
Open$34.02
Prev close$34.26
Day range$34.00 – $36.57
Volume385.0K
Market cap$1.10B
P/E (TTM)–
Dividend yield–

Ownership & positioning

Who holds it, who is betting against it, and where the big money is moving

Institutional ownership100.5%-12.64 pts vs. prior quarter
Institutions holding146+0 vs. prior quarter
Insider trades (recent)26 buys / 9 sellsNet buying
Short interest17.41% of floatDays to cover 21.5 · as of 15 Sep 2026
Short-sale volume share18.2%5-day average of daily volume

Short-sale volume as % of daily volume

11%18%25%33%Sep '26Sep '26Oct '26

Large-order net flow, last 20 sessions

Net of large-order buying minus selling, in USD. Over this window: −$1.91M (8 inflow days, 12 outflow days).

Net flow by order size, last 20 sessions

−$675.6KSuper−$1.2MBig−$1.2MMid−$4.6MSmall

Super/Big orders approximate institutional-size trades; Mid/Small approximate retail-size trades. Net buy minus sell value in each bucket, summed over the window.

The five largest holders on file together own 35.1% of shares outstanding.

Largest holders

  • Deep Track Capital, LP10.39%
  • BlackRock8.48%
  • RA Capital Management, L.P.6.85%
  • Trails Edge Capital Partners, LP4.72%
  • Commodore Capital LP4.65%
  • J.P. Morgan Asset Management, Inc.4.53%
  • TCG Crossover Management, LLC4.49%
  • Caligan Partners, LP4.46%

By investor type

  • Hedge Fund34.31%
  • VC/PE Fund34.26%
  • Mutual Fund27.99%
  • Public Company2.73%
  • Individual/Insider0.73%
  • Sovereign Wealth Fund0.50%
  • Private Company0.48%
  • Insurance Company0.14%

Reported short interest has risen from 15.87% to 17.41% of float over the last 6 biweekly reports (30 Jun 2026 to 15 Sep 2026).

Recent institutional activity

HolderTypePeriodShare changeNew stake
Nuveen Asset Management LLC Insurance Company 2026/Q3 +45,220 0.1%
Boothbay Fund Management, LLC Hedge Fund 2026/Q3 +275,675 0.9%
BlackRock Mutual Fund 2026/Q3 +263,460 8.5%
Trails Edge Capital Partners, LP Hedge Fund 2026/Q3 +203,660 4.7%
The Goldman Sachs Group, Inc. Public Company 2026/Q3 +201,423 1.8%
Millennium Management LLC Hedge Fund 2026/Q3 +122,253 0.8%
Columbia Management Investment Advisers, LLC Mutual Fund 2026/Q3 +119,178 0.7%
State Street Global Advisors Mutual Fund 2026/Q3 +97,655 1.9%
Geode Capital Management, LLC Mutual Fund 2026/Q3 +94,565 1.9%
Raymond James Financial, Inc. Public Company 2026/Q3 +91,656 0.3%
Eversept Partners, L.P. Hedge Fund 2026/Q3 +83,465 0.6%
Longbow Finance SA Mutual Fund 2026/Q3 +82,336 0.3%
BNP Paribas Financial Markets SNC Private Company 2026/Q3 +82,319 0.3%
Vanguard Capital Management, LLC Mutual Fund 2026/Q3 +81,887 3.5%
J.P. Morgan Asset Management, Inc. Mutual Fund 2026/Q3 +70,819 4.5%

Institutional buy/sell activity by reporting period, largest moves first.

Insider transactions

DateInsiderTitleTransactionSharesPriceHeld after
29 Jul 2026 David Kroin Open Market Derivative Acquisiti +286,205 $0.00 664,649
8 Jun 2026 Zachary Prensky Intent to Sell (Form 144) -16,500 $29.49 –
2 Jun 2026 Robert Richard Ruffolo Independent Director Other Derivative Acquisition +10,000 $27.95 10,000
2 Jun 2026 Ran Nussbaum Independent Director Other Derivative Acquisition +10,000 $27.95 10,000
2 Jun 2026 William Kane Former Independent Director Other Derivative Acquisition +10,000 $27.95 10,000
2 Jun 2026 Scott Garland Independent Chairman of Board Other Derivative Acquisition +10,000 $27.95 10,000
2 Jun 2026 Rebecca Luse Independent Director Other Derivative Acquisition +10,000 $27.95 10,000
2 Jun 2026 Rekha Hemrajani Former Independent Director Other Derivative Acquisition +10,000 $27.95 10,000
2 Jun 2026 Robert Lenz Director Other Derivative Acquisition +12,500 $27.95 12,500
5 Mar 2026 Robert Lenz Director Other Derivative Acquisition +20,000 $23.78 20,000
5 Feb 2026 Deep Track Capital, LP Open Market Derivative Acquisiti +472,369 $0.00 93,925
9 Dec 2025 Kaya Pai Panandiker Chief Commercial Officer Other Derivative Acquisition +195,000 $21.36 195,000
11 Sep 2025 Pontifax Venture Capital Private Acquisition +1,000,000 $15.00 1,000,000
11 Sep 2025 Pontifax Venture Capital Derivative Exercise and Retained +411,681 – 1,000,000
11 Sep 2025 Deep Track Capital, LP Private Acquisition +2,666,666 $15.00 666,666
11 Sep 2025 Deep Track Capital, LP Derivative Exercise and Retained +686,138 – 666,666
11 Sep 2025 Deep Track Capital, LP Initial Statement of Beneficial +0 – 666,666
9 Sep 2025 Robert Richard Ruffolo Independent Director Derivative Sale to Issuer -13,266 – –
9 Sep 2025 Robert Richard Ruffolo Independent Director Other Derivative Acquisition +35,715 $15.00 22,449
9 Sep 2025 Robert Richard Ruffolo Independent Director Initial Statement of Beneficial +0 – 13,266

From Form 4/Form 144 filings. Negative share counts are disposals (sales, gifts, or shares withheld for taxes); positive are acquisitions.

Short interest, by report

Report dateShares short% of floatDays to cover
15 Sep 2026 5,617,182 17.4% 21.5
31 Aug 2026 5,278,529 16.4% 19.9
14 Aug 2026 5,156,413 16.0% 12.4
31 Jul 2026 4,746,857 16.6% 12.8
15 Jul 2026 4,260,793 14.9% 17.6
30 Jun 2026 4,550,288 15.9% 9.8

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