Stocks › Biotechnology › OABI

OmniAb OABI

US equityMarket cap rank #3551Biotechnology

$4.56 +$0.21 (+4.83%)

Pre-market · Oct 8, 8:20 am ET · After hours $4.61 +1.10%

Open$4.35

Prev close$4.35

Day range$4.30 – $4.75

Volume1.50M

Market cap$662.98M

P/E (TTM)–

Dividend yield–

Ownership & positioning

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

Institutional ownership47.4%-0.12 pts vs. prior quarter

Institutions holding171-2 vs. prior quarter

Insider trades (recent)37 buys / 13 sellsNet buying

Short interest4.90% of floatDays to cover 4.1 · as of 15 Sep 2026

Short-sale volume share17.9%5-day average of daily volume

Short-sale volume as % of daily volume

Large-order net flow, last 20 sessions

Net of large-order buying minus selling, in USD. Over this window: +$377.7K (9 inflow days, 11 outflow days).

Net flow by order size, last 20 sessions

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 25.1% of shares outstanding.

Largest holders

Whitefort Capital Management, LP7.05%
BlackRock6.12%
Robert Goldstein5.20%
Nomura Holdings, Inc.3.46%
Gotham Asset Management, LLC3.26%
Vanguard Capital Management, LLC3.17%
Cadian Capital Management, LP2.90%
Matthew Foehr2.77%

By investor type

Mutual Fund23.55%
Hedge Fund16.85%
Individual/Insider11.62%
Public Company3.92%
VC/PE Fund2.70%
Insurance Company0.14%
Family Office/Trust0.13%
Private Company0.12%

Reported short interest has risen from 3.28% to 4.90% of float over the last 6 biweekly reports (30 Jun 2026 to 15 Sep 2026).

Recent institutional activity

Holder	Type	Period	Share change	New stake
Nuveen Asset Management LLC	Insurance Company	2026/Q3	+199,954	0.1%
Nomura Holdings, Inc.	Public Company	2026/Q3	+4,323,112	3.5%
BlackRock	Mutual Fund	2026/Q3	+790,609	6.1%
Mackenzie Financial Corporation	Mutual Fund	2026/Q3	+489,134	0.3%
Renaissance Technologies Corp.	Hedge Fund	2026/Q3	+330,750	0.4%
ADAR1 Capital Management, LLC	Hedge Fund	2026/Q3	+242,222	0.7%
TowerView LLC	Hedge Fund	2026/Q3	+180,000	0.8%
D. E. Shaw & Co., L.P.	Hedge Fund	2026/Q3	+179,150	0.4%
Palumbo Wealth Management LLC	Family Office/Trust	2026/Q3	+161,975	0.1%
Arrowstreet Capital, Limited Partnership	Mutual Fund	2026/Q3	+159,621	0.1%
Two Sigma Investments, LP	Hedge Fund	2026/Q3	+144,691	0.5%
Walleye Capital LLC	Hedge Fund	2026/Q3	+144,427	0.1%
Acadian Asset Management LLC	Mutual Fund	2026/Q3	+132,385	0.1%
Vanguard Portfolio Management, LLC	Mutual Fund	2026/Q3	+76,617	0.7%
Northern Trust Global Investments	Mutual Fund	2026/Q3	+67,399	0.7%

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

Insider transactions

Date	Insider	Title	Transaction	Shares	Price	Held after
31 Jul 2026	Amechi Nwachuku	Executive VP & Chief Operating Officer	Other Derivative Acquisition	+800,000	$1.98	800,000
16 Jun 2026	John Higgins	Chairperson	Other Derivative Acquisition	+20,000	–	20,000
16 Jun 2026	John Higgins	Chairperson	Other Derivative Acquisition	+40,000	$2.03	40,000
16 Jun 2026	John Higgins	Chairperson	Derivative Exercise and Retained	+20,000	–	2,962,320
16 Jun 2026	Carolyn Bertozzi	Independent Director	Other Derivative Acquisition	+20,000	–	20,000
16 Jun 2026	Carolyn Bertozzi	Independent Director	Other Derivative Acquisition	+40,000	$2.03	40,000
16 Jun 2026	Carolyn Bertozzi	Independent Director	Derivative Exercise and Retained	+20,000	–	113,308
16 Jun 2026	Steven Love	Independent Director	Other Derivative Acquisition	+20,000	–	33,334
16 Jun 2026	Steven Love	Independent Director	Other Derivative Acquisition	+40,000	$2.03	40,000
16 Jun 2026	Steven Love	Independent Director	Derivative Exercise and Retained	+20,000	–	91,666
16 Jun 2026	Philip Gotwals	Director	Other Derivative Acquisition	+20,000	–	46,667
16 Jun 2026	Philip Gotwals	Director	Other Derivative Acquisition	+40,000	$2.03	40,000
16 Jun 2026	Philip Gotwals	Director	Derivative Exercise and Retained	+20,000	–	33,333
16 Jun 2026	Steven Crouse	Director	Other Derivative Acquisition	+20,000	–	46,667
16 Jun 2026	Steven Crouse	Director	Other Derivative Acquisition	+40,000	$2.03	40,000
16 Jun 2026	Steven Crouse	Director	Derivative Exercise and Retained	+20,000	–	33,333
16 Jun 2026	Jennifer Cochran	Independent Director	Other Derivative Acquisition	+20,000	–	20,000
16 Jun 2026	Jennifer Cochran	Independent Director	Other Derivative Acquisition	+40,000	$2.03	40,000
16 Jun 2026	Jennifer Cochran	Independent Director	Derivative Exercise and Retained	+20,000	–	174,198
20 Apr 2026	Philip Gotwals	Director	Derivative Exercise and Retained	+13,333	–	13,333

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 date	Shares short	% of float	Days to cover
15 Sep 2026	7,125,743	4.9%	4.1
31 Aug 2026	5,983,139	4.1%	1.9
14 Aug 2026	6,245,027	4.3%	6.5
31 Jul 2026	5,997,131	4.1%	17.7
15 Jul 2026	5,877,116	4.1%	10.3
30 Jun 2026	4,754,413	3.3%	6.4

Discussion

No comments yet — be the first to weigh in on OABI.