Cytosorbents CTSO Insider Ownership

NASDAQ CTSO
$6.33 -0.52 (-7.59%)
At close: Sep 9, 2026 · 4:00 PM EDT

Insider Holdings by Owner

4.76Mn Shares

Insider Ownership Statistics

as of 30 Sep, 2026
Insider Ownership
6.27%
0% pp QoQ
Shares Held by Insiders
3.93Mn
filed for Sep 2026
0.00% QoQ
Shares Outstanding
62.75Mn
62,753,959 shares
Direct Holdings
3.84Mn
Indirect: 90.70K
Net Shares Traded (QoQ)
0
no net change in Sep 2026
Insiders Holding Shares
10
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

Quarter ending 30 Sep, 2026

As of September 09, 2026, the three largest insider holders of CTSO are Phillip P. Chan (Chief Executive Officer, 1.74Mn shares), Phillip P. Chan (Chief Executive Officer, 1.48Mn shares), Vincent Capponi (President And Coo, 766.27K shares).

Form 4 Holdings

Insiders Holding CTSO

Insiders 10
Shares held 4.76Mn
Of outstanding 7.59%
# Insider Position Direct Indirect Total Share of Insiders Last Filed
1 Phillip P. Chan Chief Executive Officer 1,744,432 0 1,744,432 36.6% 15 Jun, 2026
2 Vincent Capponi President And Coo 766,268 0 766,268 16.1% 08 Aug, 2025
3 Peter J Mariani Chief Financial Officer 638,113 0 638,113 13.4% 16 Jun, 2026
4 Kathleen P. Bloch Chief Financial Officer 532,941 0 532,941 11.2% 04 Apr, 2024
5 Efthymios Deliargyris Chief Medical Officer 473,025 0 473,025 9.9% 08 Aug, 2025
6 Michael G. Bator Director 151,273 0 151,273 3.2% 04 Mar, 2025
7 Alan D. Sobel Director 145,757 0 145,757 3.1% 26 Feb, 2025
8 Al Kraus Director 142,046 0 142,046 3.0% 08 Feb, 2023
9 Edward Raymond Jones Director 88,834 0 88,834 1.9% 15 Dec, 2023
10 Jiny Kim Director 77,819 0 77,819 1.6% 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

937 Insider Transactions

Source SEC Form 4
Latest quarter Sep 2026
Download Data
Date Insider Position Transaction Shares Price Value Shares Held After Ownership
15 Jun, 2026 Peter J Mariani Chief Financial Officer Acquired P 100,000 $0.44 $44.00K 638,113 Direct
12 Jun, 2026 Phillip P. Chan Chief Executive Officer Acquired P 251,136 $0.40 $100.45K 1,734,099 Direct
15 Jun, 2026 Phillip P. Chan Chief Executive Officer Acquired P 10,333 $0.43 $4.44K 1,744,432 Direct
18 Nov, 2025 Phillip P. Chan Chief Executive Officer Acquired A 100,000 $0.64 $64.00K 1,482,963 Direct
08 Aug, 2025 Peter J Mariani Chief Financial Officer Acquired A 71,500 $0.00 $0 538,113 Direct
08 Aug, 2025 Efthymios Deliargyris Chief Medical Officer Acquired A 70,000 $0.00 $0 473,025 Direct
08 Aug, 2025 Phillip P. Chan Chief Executive Officer Acquired A 105,600 $0.00 $0 1,382,963 Direct
08 Aug, 2025 Efthymios Deliargyris Chief Medical Officer Acquired A 70,000 $0.00 $0 473,025 Direct
08 Aug, 2025 Peter J Mariani Chief Financial Officer Acquired A 71,500 $0.00 $0 538,113 Direct
08 Aug, 2025 Peter J Mariani Chief Financial Officer Acquired A 71,500 $0.00 $0 538,113 Direct
08 Aug, 2025 Peter J Mariani Chief Financial Officer Acquired A 71,500 $0.00 $0 538,113 Direct
08 Aug, 2025 Vincent Capponi President And Coo Acquired A 89,100 $0.00 $0 766,268 Direct
08 Aug, 2025 Peter J Mariani Chief Financial Officer Acquired A 90,000 $0.00 $0 90,000 Direct
08 Aug, 2025 Efthymios Deliargyris Chief Medical Officer Acquired A 95,000 $0.00 $0 95,000 Direct
08 Aug, 2025 Peter J Mariani Chief Financial Officer Acquired A 90,000 $0.00 $0 90,000 Direct
08 Aug, 2025 Jiny Kim Director Acquired A 22,000 $0.00 $0 22,000 Direct
08 Aug, 2025 Jiny Kim Director Acquired A 22,000 $0.00 $0 22,000 Direct
08 Aug, 2025 Peter J Mariani Chief Financial Officer Acquired A 90,000 $0.00 $0 90,000 Direct
08 Aug, 2025 Vincent Capponi President And Coo Acquired A 111,100 $0.00 $0 111,100 Direct
08 Aug, 2025 Jiny Kim Director Acquired A 22,000 $0.00 $0 22,000 Direct