Cytosorbents CTSO Insider Ownership

NASDAQ CTSO

$5.45 +0.13 (+2.44%)

As of: Oct 21, 2026 · 3:35 PM EDT

Insider Holdings by Owner

256.47K Shares

Insider Ownership Statistics

as of 30 Sep, 2026

Insider Ownership

7.09%

▲+0.587% pp QoQ

Shares Held by Insiders

222.82K

filed for Sep 2026

▲+9.03% QoQ

Shares Outstanding

3.14Mn

3,142,137 shares

Direct Holdings

222.72K

Indirect: 100

Net Shares Traded (QoQ)

+18.45K

net buying in Sep 2026

Insiders Holding Shares

with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Insiders

Bought Sold

Latest quarter —

Net over range —

Buying quarters —

Insider Ownership Summary

Updated Oct 10, 2026

Over the trailing 12 months, CTSO insiders bought $269,332 worth of shares in open-market trades, with no open-market sales.

Cytosorbents' open-market purchases in the past 12 months came from 4 insiders; no insider sold.
Among Cytosorbents' insiders, Phillip P. Chan (Chief Executive Officer) was the largest open-market buyer over the past 12 months, purchasing $197,542 of stock, most recently on September 15, 2026.
Per Business Quant, CTSO insiders together hold 222.82K shares based on their latest Form 4 filings, up 9.03% from 204.38K shares (split-adjusted) at the end of Q2 2026 and up 5.95% from 210.3K shares (split-adjusted) at the end of Q3 2025.
Direct holdings account for 222.72K shares (99.96%) of CTSO's insider total, and indirect holdings through trusts, partnerships and family members for 100 shares (0.04%).
The insider holdings in Cytosorbents belong to 8 insiders who have reported on Form 4 within the past two years.
Cytosorbents' three biggest insider holders are Phillip P. Chan (Chief Executive Officer, 101K shares), Vincent Capponi (President and COO, 40.39K shares) and Peter J. Mariani (Chief Financial Officer, 31.91K shares), based on their latest Form 4 filings.
Phillip P. Chan alone accounts for 45.33% of the shares held by Cytosorbents insiders.
Institutions held 24.77% of Cytosorbents' outstanding shares in their Q2 2026 13F filings, insiders about 7.09% based on their latest Form 4 filings, and other investors, including the public, the remaining 68.14%.
Over the trailing 12 months, 4 insiders reported transactions in CTSO stock across 7 Form 4 filings.
The insider holdings and trades above for Cytosorbents reflect Form 4 filings through September 16, 2026.

Form 4 Holdings

Insiders Holding CTSO

Insiders 10

Shares held 256.47K

Of outstanding 8.16%

#	Insider	Position	Direct	Total	Share of Insiders	Last Filed
1	Phillip P. Chan	Chief Executive Officer	100,996	100,996	39.4%	16 Sep, 2026
2	Vincent Capponi	President And Coo	40,387	40,387	15.7%	16 Sep, 2026
3	Peter J Mariani	Chief Financial Officer	31,906	31,906	12.4%	16 Jun, 2026
4	Kathleen P. Bloch	Chief Financial Officer	26,647	26,647	10.4%	04 Apr, 2024
5	Efthymios Deliargyris	Chief Medical Officer	23,651	23,651	9.2%	08 Aug, 2025
6	Alan D. Sobel	Director	9,887	9,887	3.9%	16 Sep, 2026
7	Michael G. Bator	Director	7,564	7,564	2.9%	04 Mar, 2025
8	Al Kraus	Director	7,102	7,102	2.8%	08 Feb, 2023
9	Edward Raymond Jones	Director	4,442	4,442	1.7%	15 Dec, 2023
10	Jiny Kim	Director	3,891	3,891	1.5%	15 Dec, 2023

Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.

Form 4 Filings

704 Insider Transactions

Source SEC Form 4

Latest quarter Sep 2026

Date	Insider	Position	Transaction	Shares	Price	Value	Shares Held After	Ownership
15 Sep, 2026	Alan D. Sobel	Director	Acquired P	1,900	$6.12	$11.63K	9,287	Direct
15 Sep, 2026	Phillip P. Chan	Chief Executive Officer	Acquired P	3,774	$6.00	$22.64K	100,996	Direct
14 Sep, 2026	Vincent Capponi	President And Coo	Acquired P	1,800	$6.07	$10.93K	40,114	Direct
15 Sep, 2026	Alan D. Sobel	Director	Acquired P	500	$6.05	$3.03K	9,787	Direct
14 Sep, 2026	Vincent Capponi	President And Coo	Acquired P	273	$5.90	$1.61K	40,387	Direct
15 Sep, 2026	Alan D. Sobel	Director	Acquired P	100	$6.01	$601	9,887	Direct
04 Sep, 2026	Phillip P. Chan	Chief Executive Officer	Acquired P	200,000	$7.00	$1.40Mn	97,222	Direct
15 Jun, 2026	Peter J Mariani	Chief Financial Officer	Acquired P	100,000	$8.80	$880.00K	31,906	Direct
12 Jun, 2026	Phillip P. Chan	Chief Executive Officer	Acquired P	251,136	$8.00	$2.01Mn	86,705	Direct
15 Jun, 2026	Phillip P. Chan	Chief Executive Officer	Acquired P	10,333	$8.60	$88.86K	87,222	Direct
18 Nov, 2025	Phillip P. Chan	Chief Executive Officer	Acquired A	100,000	$12.80	$1.28Mn	74,148	Direct
08 Aug, 2025	Efthymios Deliargyris	Chief Medical Officer	Acquired A	70,000	$0.00	$0	23,651	Direct
08 Aug, 2025	Peter J Mariani	Chief Financial Officer	Acquired A	71,500	$0.00	$0	26,906	Direct
08 Aug, 2025	Phillip P. Chan	Chief Executive Officer	Acquired A	105,600	$0.00	$0	69,148	Direct
08 Aug, 2025	Vincent Capponi	President And Coo	Acquired A	89,100	$0.00	$0	38,313	Direct
08 Aug, 2025	Peter J Mariani	Chief Financial Officer	Acquired A	90,000	$0.00	$0	4,500	Direct
08 Aug, 2025	Efthymios Deliargyris	Chief Medical Officer	Acquired A	95,000	$0.00	$0	4,750	Direct
08 Aug, 2025	Vincent Capponi	President And Coo	Acquired A	111,100	$0.00	$0	5,555	Direct
08 Aug, 2025	Jiny Kim	Director	Acquired A	22,000	$0.00	$0	1,100	Direct
08 Aug, 2025	Edward Raymond Jones	Director	Acquired A	22,000	$0.00	$0	1,100	Direct

Showing 1 to 20 of 704 transactions