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Puma Biotechnology PBYI

US equityMarket cap rank #3746Biotechnology
$9.60 −$0.22 (-2.19%)
Market open · Oct 8, 10:00 am ET · After hours $9.81 0.00%
Open$9.75
Prev close$9.81
Day range$9.59 – $9.75
Volume19.4K
Market cap$495.29M
P/E (TTM)18.8
Dividend yield–

Ownership & positioning

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

Institutional ownership75.5%-1.22 pts vs. prior quarter
Institutions holding194+1 vs. prior quarter
Insider trades (recent)13 buys / 37 sellsNet selling
Short interest8.37% of floatDays to cover 13.8 · as of 15 Sep 2026
Short-sale volume share27.6%5-day average of daily volume

Short-sale volume as % of daily volume

18%23%29%34%Sep '26Sep '26Oct '26

Large-order net flow, last 20 sessions

Net of large-order buying minus selling, in USD. Over this window: −$682.6K (8 inflow days, 12 outflow days).

Net flow by order size, last 20 sessions

−$458.1KSuper−$224.5KBig−$146.4KMid−$563.5KSmall

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 37.7% of shares outstanding.

Largest holders

  • Alan Auerbach13.74%
  • Acorn Bioventures8.00%
  • BlackRock7.37%
  • American Century Investment Management4.49%
  • Vanguard Capital Management, LLC4.08%
  • Acadian Asset Management LLC3.98%
  • Renaissance Technologies Corp.3.56%
  • Vanguard Portfolio Management, LLC3.54%

By investor type

  • Mutual Fund56.76%
  • Individual/Insider15.18%
  • VC/PE Fund8.00%
  • Hedge Fund7.38%
  • Government Pension Fund1.32%
  • Public Company1.03%
  • Private Company0.47%
  • Family Office/Trust0.32%

Reported short interest has risen from 7.13% to 8.37% of float over the last 6 biweekly reports (30 Jun 2026 to 15 Sep 2026).

Insider transactions

DateInsiderTitleTransactionSharesPriceHeld after
13 Sep 2026 Troy Wilson Independent Director Open Market Disposition -5,000 $9.10 28,300
13 Sep 2026 Alessandra Cesano Director Open Market Disposition -12,150 $9.12 29,700
13 Sep 2026 Alessandra Cesano Director Derivative Exercise and Sale -50,000 $9.12 29,700
5 Jul 2026 Alan Auerbach Founder, Chairman, President, CEO & Secretary Automatic Disposition -44,058 $8.26 7,092,238
5 Jul 2026 Douglas Hunt Senior Vice President of Regulatory Affairs, Pharmacovigilance, Medical Affairs & Law Automatic Disposition -8,460 $8.26 147,766
5 Jul 2026 Maximo Nougues Chief Financial Officer Automatic Disposition -9,386 $8.26 180,219
11 Jun 2026 Jay Moyes Lead Independent Director Automatic Disposition -22,000 $7.22 31,322
11 Jun 2026 Troy Wilson Independent Director Automatic Disposition -10,800 $7.20 33,300
11 Jun 2026 Adrian Senderowicz Independent Director Automatic Disposition -27,000 $7.20 –
11 Jun 2026 Allison Dorval Independent Director Automatic Disposition -11,610 $7.20 63,780
11 Jun 2026 Brian Stuglik Independent Director Automatic Disposition -8,100 $7.20 86,858
10 Jun 2026 Jay Moyes Lead Independent Director Other Acquisition +27,000 – 27,000
10 Jun 2026 Michael Miller Independent Director Other Acquisition +27,000 – 27,000
10 Jun 2026 Troy Wilson Independent Director Other Acquisition +27,000 – 27,000
10 Jun 2026 Alessandra Cesano Director Other Acquisition +27,000 – 27,000
10 Jun 2026 Adrian Senderowicz Independent Director Other Acquisition +27,000 – 27,000
10 Jun 2026 Allison Dorval Independent Director Other Acquisition +27,000 – 27,000
10 Jun 2026 Brian Stuglik Independent Director Other Acquisition +27,000 – 27,000
17 Feb 2026 Alan Auerbach Founder, Chairman, President, CEO & Secretary Other Acquisition +159,778 – 258,978
17 Feb 2026 Alan Auerbach Founder, Chairman, President, CEO & Secretary Other Derivative Acquisition +227,474 $6.68 227,474

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 4,319,663 8.4% 13.8
31 Aug 2026 4,274,524 8.3% 15.6
14 Aug 2026 4,167,830 8.1% 11.4
31 Jul 2026 4,126,395 8.1% 13.9
15 Jul 2026 3,909,380 7.7% 10.7
30 Jun 2026 3,628,478 7.1% 8.5

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