Stocks › Biotechnology › RGNX

Regenxbio RGNX

US equityMarket cap rank #3741Biotechnology

$7.56 −$0.04 (-0.53%)

Market open · Oct 8, 10:00 am ET · After hours $7.61 +0.21%

Open$7.50

Prev close$7.60

Day range$7.44 – $7.58

Volume82.9K

Market cap$498.73M

P/E (TTM)–

Dividend yield–

Ownership & positioning

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

Institutional ownership66.1%-13.45 pts vs. prior quarter

Institutions holding206+2 vs. prior quarter

Insider trades (recent)33 buys / 17 sellsNet buying

Short interest12.01% of floatDays to cover 7.7 · as of 15 Sep 2026

Short-sale volume share24.4%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: −$1.15M (10 inflow days, 10 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 29.3% of shares outstanding.

Largest holders

BlackRock9.69%
Redmile Group, LLC6.62%
Allan Fox4.82%
State Street Global Advisors4.50%
Vanguard Capital Management, LLC3.70%
J.P. Morgan Asset Management, Inc.3.24%
Morgan Stanley2.90%
Vanguard Portfolio Management, LLC2.05%

By investor type

Mutual Fund37.71%
Hedge Fund18.35%
Individual/Insider6.69%
Public Company5.93%
Insurance Company1.46%
Private Company1.43%
VC/PE Fund1.12%
Government Pension Fund0.07%

Reported short interest has fallen from 20.23% to 12.01% of float over the last 6 biweekly reports (30 Jun 2026 to 15 Sep 2026).

Insider transactions

Date	Insider	Title	Transaction	Shares	Price	Held after
31 Aug 2026	Mitchell Chan	Chief Financial Officer	Sale to Issuer	-4,902	$9.32	19,632
31 Aug 2026	Craig Malzahn	Executive Vice President, Product Development & CTO	Sale to Issuer	-234	$9.32	81,960
26 Aug 2026	Gregory Ciongoli	Independent Director	Open Market Acquisition	+102,603	$9.36	102,603
24 Aug 2026	Gregory Ciongoli	Independent Director	Other Acquisition	+15,432	–	15,432
24 Aug 2026	Gregory Ciongoli	Independent Director	Other Derivative Acquisition	+69,609	$8.91	69,609
31 Jul 2026	Stephen Pakola	Chief Medical Officer	Sale to Issuer	-7,468	$9.69	52,802
31 Jul 2026	Patrick Christmas	Chief Legal Officer	Sale to Issuer	-4,699	$9.69	97,927
1 Jul 2026	Stephen Pakola	Chief Medical Officer	Derivative Exercise and Sale	-2,161	$13.64	45,673
30 Jun 2026	Curran Simpson	Chief Operating Officer	Sale to Issuer	-6,818	$13.09	54,559
30 Jun 2026	Stephen Pakola	Chief Medical Officer	Derivative Exercise and Sale	-36,725	$12.86	45,673
29 Jun 2026	Curran Simpson	Chief Operating Officer	Other Acquisition	+2,404	$10.18	54,559
28 Jun 2026	Stephen Pakola	Chief Medical Officer	Automatic Disposition	-19,608	$11.04	45,673
28 May 2026	David Stump	Independent Director	Other Acquisition	+9,807	–	9,807
28 May 2026	David Stump	Independent Director	Other Derivative Acquisition	+46,600	$7.01	46,600
28 May 2026	George Migausky	Independent Director	Other Acquisition	+9,807	–	9,807
28 May 2026	George Migausky	Independent Director	Other Derivative Acquisition	+46,600	$7.01	46,600
28 May 2026	Argeris Karabelas	Lead Independent Director	Other Acquisition	+9,807	–	9,807
28 May 2026	Argeris Karabelas	Lead Independent Director	Other Derivative Acquisition	+46,600	$7.01	46,600
28 May 2026	Allan Fox	Chairperson	Other Acquisition	+9,807	–	9,807
28 May 2026	Allan Fox	Chairperson	Other Derivative Acquisition	+46,600	$7.01	46,600

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	7,927,603	12.0%	7.7
31 Aug 2026	7,497,221	11.4%	4.9
14 Aug 2026	8,197,515	12.4%	7.8
31 Jul 2026	7,194,939	11.7%	3.8
15 Jul 2026	8,626,772	16.7%	3.3
30 Jun 2026	10,459,575	20.2%	3.2

Discussion

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