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Ardelyx ARDX

US equityMarket cap rank #3373Biotechnology

$3.26 −$0.05 (-1.51%)

Market closed · Oct 8, 7:10 am ET · Last extended-hours $3.28 +0.61%

Open$3.26

Prev close$3.31

Day range$3.22 – $3.35

Volume5.39M

Market cap$841.69M

P/E (TTM)–

Dividend yield–

Ownership & positioning

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

Institutional ownership72.6%+0.05 pts vs. prior quarter

Institutions holding290+1 vs. prior quarter

Insider trades (recent)16 buys / 32 sellsNet selling

Short interest9.92% of floatDays to cover 6.3 · as of 15 Sep 2026

Short-sale volume share26.8%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: +$4.23M (16 inflow days, 4 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 31.8% of shares outstanding.

Largest holders

BlackRock9.43%
Rubric Capital Management LP6.50%
Millennium Management LLC5.58%
State Street Global Advisors5.36%
Vanguard Capital Management, LLC4.91%
Macquarie Investment Management Business Trust3.83%
Vanguard Portfolio Management, LLC3.22%
Geode Capital Management, LLC2.57%

By investor type

Mutual Fund45.51%
Hedge Fund21.45%
Individual/Insider3.38%
Public Company2.95%
Insurance Company1.07%
Private Company1.06%
Government Pension Fund0.39%
Family Office/Trust0.16%

Reported short interest has fallen from 10.27% to 9.92% 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
Rubric Capital Management LP	Hedge Fund	2026/Q3	+14,341,804	6.5%
Aigh Capital Management, LLC	Hedge Fund	2026/Q3	+3,200,000	1.3%
BlackRock	Mutual Fund	2026/Q3	+2,340,498	9.4%
Macquarie Investment Management Business Trust	Mutual Fund	2026/Q3	+1,377,363	3.8%
Vanguard Portfolio Management, LLC	Mutual Fund	2026/Q3	+1,365,081	3.2%
Invesco Capital Management LLC	Mutual Fund	2026/Q3	+1,045,994	0.5%
Two Sigma Investments, LP	Hedge Fund	2026/Q3	+935,780	2.1%
PanAgora Asset Management, Inc.	Mutual Fund	2026/Q3	+890,944	0.4%
Goldman Sachs Asset Management, L.P.	Mutual Fund	2026/Q3	+832,093	0.6%
ExodusPoint Capital Management, LP	Hedge Fund	2026/Q3	+752,923	0.3%
Schroder Investment Management Limited	Mutual Fund	2026/Q3	+741,470	0.5%
Morgan Stanley	Public Company	2026/Q3	+672,916	0.9%
Leap Investments LP	Mutual Fund	2026/Q3	+529,118	0.2%
Hussman Strategic Advisors Inc	Mutual Fund	2026/Q3	+420,000	0.2%
Geode Capital Management, LLC	Mutual Fund	2026/Q3	+394,281	2.6%

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

Insider transactions

Date	Insider	Title	Transaction	Shares	Price	Held after
20 Aug 2026	Michael Raab	Chief Executive Officer	Private Disposition	-58,574	$3.86	1,645,156
20 Aug 2026	John Bishop		Private Disposition	-19,750	$3.86	317,095
20 Aug 2026	James Brady	Chief Human Resources Officer	Private Disposition	-15,136	$3.86	245,930
20 Aug 2026	Laura Williams	Chief Medical Officer	Private Disposition	-10,739	$3.86	367,456
20 Aug 2026	Eric Foster	Chief Commercial Officer	Private Disposition	-8,562	$3.86	409,410
20 Aug 2026	Mike Kelliher	Executive Vice President of Corporate Development & Strategy	Private Disposition	-7,758	$3.86	349,660
20 Aug 2026	Joseph Reilly	Senior VP of Finance & Principal Accounting Officer	Private Disposition	-3,982	$3.86	145,854
20 Aug 2026	Sue Hohenleitner	Chief Financial Officer	Private Disposition	-1,558	$3.86	227,520
14 Jul 2026	Michael Raab	Chief Executive Officer	Automatic Disposition	-20,834	$5.06	1,703,730
14 Jul 2026	Michael Raab	Chief Executive Officer	Derivative Exercise and Sale	-20,834	$5.06	1,703,730
17 Jun 2026	Laura Williams	Chief Medical Officer	Automatic Disposition	-50,898	$5.99	378,195
17 Jun 2026	Laura Williams	Chief Medical Officer	Derivative Exercise and Sale	-31,000	$5.99	378,195
15 Jun 2026	David Mott	Independent Chairperson	Other Acquisition	+20,282	–	3,312,812
15 Jun 2026	David Mott	Independent Chairperson	Other Acquisition	+26,455	–	36,843
15 Jun 2026	David Mott	Independent Chairperson	Other Derivative Acquisition	+39,715	$5.67	39,715
15 Jun 2026	Robert Bazemore	Independent Director	Other Acquisition	+26,455	–	36,842
15 Jun 2026	Robert Bazemore	Independent Director	Other Derivative Acquisition	+39,715	$5.67	39,715
15 Jun 2026	William Charles Bertrand	Independent Director	Other Acquisition	+12,345	–	292,664
15 Jun 2026	William Charles Bertrand	Independent Director	Other Acquisition	+26,455	–	36,843
15 Jun 2026	William Charles Bertrand	Independent Director	Other Derivative Acquisition	+39,715	$5.67	39,715

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	25,602,541	9.9%	6.3
31 Aug 2026	22,716,201	8.8%	6.1
14 Aug 2026	22,433,157	8.7%	3.3
31 Jul 2026	26,239,226	10.6%	11.0
15 Jul 2026	26,248,733	10.6%	8.1
30 Jun 2026	25,366,491	10.3%	4.0

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