Cytosorbents Corp (CTSO) shareholders
CTSONasdaqSurgical & Medical Instruments & ApparatusFiscal year ends December 31
$4.87−0.50 (-9.31%)
Close on Nov 13, 2026Market cap $306.04MP/E –Yield –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
1.3%
1M of 63M shares
Institutional holders
51
8 new, 7 sold out
Net institutional buying
-0M
In Q2 2026
Insider trades, 12 months
10 buys · 0 sales
Net bought $269.33K
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| Avenir Corp Joint filing with James H. Rooney (8.30%) | 5,230,099 | 8.30% | 13G (passive) amendment | Dec 31, 2025 |
| Thomas A. Satterfield, Jr. | 3,998,867 | 6.56% | 13G (passive) | Jan 13, 2025 |
| Avenue Capital Management II, L.P. Joint filing with Marc Lasry (5.70%) | 3,755,273 | 5.70% | 13G (passive) | Jun 26, 2024 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of CTSO | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| Avenir Corp | 259,461 | 0.41% | $1.94M | −1,328 | 0.24% |
| Neuberger Berman Group LLC | 98,435 | 0.16% | $740.52K | +14,285 | 0.00% |
| Vanguard Capital Management LLC | 95,703 | 0.15% | $715.86K | +1,704 | 0.00% |
| CM Management, LLC | 73,825 | 0.12% | $552.21K | – | 0.37% |
| Skylands Capital, LLC | 60,570 | 0.10% | $453.06K | −24,805 | 0.06% |
| BlackRock, Inc. | 31,361 | 0.05% | $234.58K | −7,789 | 0.00% |
| Geode Capital Management, LLC | 30,103 | 0.05% | $225.24K | −5,260 | 0.00% |
| Sargent Investment Group, LLC | 27,788 | 0.04% | $207.85K | +293 | 0.02% |
| Pathstone Holdings, LLC | 24,996 | 0.04% | $186.97K | −2 | 0.00% |
| Vanguard Fiduciary Trust Co | 15,808 | 0.03% | $118.25K | +115 | 0.00% |
| CIBC Bancorp USA Inc. | 8,632 | 0.01% | $64.57K | – | 0.00% |
| State Street Corp | 7,965 | 0.01% | $59.58K | – | 0.00% |
| Osaic Holdings, Inc. | 6,742 | 0.01% | $49.99K | +221 | 0.00% |
| UBS Group AG | 6,551 | 0.01% | $49.00K | +791 | 0.00% |
| Northern Trust Corp | 5,583 | 0.01% | $41.76K | +956 | 0.00% |
| Raymond James Financial Inc | 5,381 | 0.01% | $40.25K | −7 | 0.00% |
| NWF Advisory Services Inc. | 5,207 | 0.01% | $38.95K | – | 0.00% |
| Renaissance Technologies LLC | 5,001 | 0.01% | $37.41K | −35 | 0.00% |
| Morgan Stanley | 4,566 | 0.01% | $34.16K | −443 | 0.00% |
| Key Client Fiduciary Advisors, LLC | 3,923 | 0.01% | $29.34K | – | 0.01% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 51 | 1M | 1.3% | 8 / 11 | 13 / 7 | 0M | 0M |
| Q1 2026 | 50 | 1M | 1.3% | 10 / 9 | 11 / 7 | 0M | 0M |
| Q4 2025 | 51 | 1M | 1.3% | 9 / 13 | 10 / 6 | 0M | 0M |
| Q3 2025 | 49 | 1M | 1.3% | 8 / 13 | 11 / 3 | 0M | 0M |
| Q2 2025 | 45 | 1M | 1.3% | 3 / 8 | 18 / 7 | 0M | 0M |
| Q1 2025 | 49 | 1M | 1.3% | 7 / 18 | 8 / 9 | 0M | 0M |
| Q4 2024 | 51 | 1M | 1.2% | 12 / 13 | 11 / 12 | 0M | 0M |
| Q3 2024 | 53 | 1M | 1.3% | 9 / 9 | 12 / 5 | 0M | 0M |
| Q2 2024 | 50 | 1M | 1.3% | 3 / 8 | 18 / 3 | 0M | 0M |
| Q1 2024 | 50 | 1M | 1.4% | 2 / 15 | 14 / 6 | 0M | 0M |
| Q4 2023 | 54 | 1M | 1.4% | 8 / 16 | 13 / 6 | 0M | 0M |
| Q3 2023 | 53 | 1M | 1.2% | 7 / 12 | 15 / 11 | 0M | 0M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
12 funds held CTSO in Q2 2026, 59% of their shares through ETFs. Each fund counts once per quarter, from its quarter-end report.
| Fund | Shares | % of CTSO | Value | % of fund | As of |
|---|---|---|---|---|---|
| Vanguard Total Stock Market Index Fund | 1,274,363 | 2.03% | $476.61K | 0.00% | Jun 30, 2026 |
| Neuberger Intrinsic Value Fund | 646,511 | 1.03% | $317.37K | 0.02% | May 31, 2026 |
| Vanguard Extended Market Index Fund | 574,463 | 0.91% | $214.85K | 0.00% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 380,268 | 0.61% | $186.67K | 0.00% | May 31, 2026 |
| Fidelity Total Market Index Fund | 94,319 | 0.15% | $46.30K | 0.00% | May 31, 2026 |
| Fidelity Series Total Market Index Fund | 78,580 | 0.13% | $38.57K | 0.00% | May 31, 2026 |
| Vanguard Balanced Index Fund | 35,641 | 0.06% | $13.33K | 0.00% | Jun 30, 2026 |
| Fidelity Nasdaq Composite Index Fund | 32,102 | 0.05% | $15.76K | 0.00% | May 31, 2026 |
| Vanguard Institutional Total Stock Market Index Fund | 29,596 | 0.05% | $11.07K | 0.00% | Jun 30, 2026 |
| Morgan Stanley Pathway Small-Mid Cap Equity ETF | 21,766 | 0.03% | $10.68K | 0.00% | May 31, 2026 |
| Column Small Cap Select Fund | 6,741 | 0.01% | $3.31K | 0.00% | May 31, 2026 |
| Column Small Cap Fund | 2,079 | 0.00% | $1.02K | 0.00% | May 31, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Phillip P. Chan | Chief Executive Officer, Director | 100,996 | 0.16% | Sep 16, 2026 |
| Vincent Capponi | President and COO | 40,114 | 0.06% | Sep 16, 2026 |
| Peter J. Mariani | Chief Financial Officer | 638,113 | 1.02% | Jun 16, 2026 |
| Efthymios Deliargyris | Chief Medical Officer | 473,025 | 0.75% | Aug 8, 2025 |
| Alan D. Sobel | Director | 11,787 | 0.02% | Sep 16, 2026 |
| Jiny Kim | Director | 77,819 | 0.12% | Aug 8, 2025 |
| Edward Raymond Jones | Director | 88,834 | 0.14% | Aug 8, 2025 |
| Michael G. Bator | Director | 151,273 | 0.24% | Aug 8, 2025 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Alan D. Sobel Director | Sep 15, 2026 | Buy | +500 | $6.05 | $3.03K | 9,787 |
| Alan D. Sobel Director | Sep 15, 2026 | Buy | +1,900 | $6.12 | $11.63K | 9,287 |
| Alan D. Sobel Director | Sep 15, 2026 | Buy | +100 | $6.01 | $601 | 9,887 |
| Phillip P. Chan Chief Executive Officer, Director | Sep 15, 2026 | Buy | +3,774 | $6.00 | $22.64K | 100,996 |
| Vincent Capponi President and COO | Sep 14, 2026 | Buy | +1,800 | $6.07 | $10.93K | 40,114 |
| Vincent Capponi President and COO | Sep 14, 2026 | Buy | +273 | $5.90 | $1.61K | 40,387 |
| Phillip P. Chan Chief Executive Officer, Director | Sep 4, 2026 | Buy | +200,000 | $0.35 | $70.00K | 1,944,432 |
| Peter J. Mariani Chief Financial Officer | Jun 15, 2026 | Buy | +100,000 | $0.44 | $44.00K | 638,113 |
| Phillip P. Chan Chief Executive Officer, Director | Jun 15, 2026 | Buy | +10,333 | $0.43 | $4.44K | 1,744,432 |
| Phillip P. Chan Chief Executive Officer, Director | Jun 12, 2026 | Buy | +251,136 | $0.40 | $100.45K | 1,734,099 |
| Phillip P. Chan Chief Executive Officer, Director | Nov 18, 2025 | Award | +100,000 | $0.64 | $64.00K | 1,482,963 |
| Peter J. Mariani Chief Financial Officer | Aug 8, 2025 | Award | +71,500 | – | – | 538,113 |
| Vincent Capponi President and COO | Aug 8, 2025 | Award | +89,100 | – | – | 766,268 |
| Phillip P. Chan Chief Executive Officer, Director | Aug 8, 2025 | Award | +105,600 | – | – | 1,382,963 |
| Efthymios Deliargyris Chief Medical Officer | Aug 8, 2025 | Award | +70,000 | – | – | 473,025 |
| Michael G. Bator Director | Feb 24, 2025 | Exercise | +10,000 | $1.13 | $11.30K | 151,273 |
| Alan D. Sobel Director | Feb 24, 2025 | Exercise | +21,950 | $1.13 | $24.80K | 145,757 |
| Phillip P. Chan Chief Executive Officer, Director | Feb 24, 2025 | Exercise | +34,168 | $1.13 | $38.61K | 1,277,363 |
| Vincent Capponi President and COO | Feb 24, 2025 | Exercise | +12,000 | $1.13 | $13.56K | 677,168 |
| Peter J. Mariani Chief Financial Officer | Feb 24, 2025 | Exercise | +32,625 | $1.13 | $36.87K | 466,613 |
| Michael G. Bator Director | Jan 17, 2025 | Option exercise | +15,879 | $1.00 | $15.88K | 141,273 |
| Vincent Capponi President and COO | Jan 17, 2025 | Option exercise | +31,760 | $1.00 | $31.76K | 665,168 |
| Alan D. Sobel Director | Jan 17, 2025 | Option exercise | +21,950 | $1.00 | $21.95K | 123,807 |
| Peter J. Mariani Chief Financial Officer | Jan 17, 2025 | Option exercise | +32,625 | $1.00 | $32.63K | 433,988 |
| Efthymios Deliargyris Chief Medical Officer | Jan 17, 2025 | Option exercise | +16,233 | $1.00 | $16.23K | 403,025 |
| Phillip P. Chan Chief Executive Officer, Director | Jan 17, 2025 | Option exercise | +90,832 | $1.00 | $90.83K | 1,243,195 |
| Peter J. Mariani Chief Financial Officer | Dec 13, 2024 | Buy | +20,000 | $0.96 | $19.20K | 401,363 |
| Peter J. Mariani Chief Financial Officer | Dec 12, 2024 | Buy | +20,000 | $0.89 | $17.80K | 381,363 |
| Peter J. Mariani Chief Financial Officer | Dec 11, 2024 | Buy | +11,363 | $0.89 | $10.11K | 361,363 |
| Peter J. Mariani Chief Financial Officer | Aug 14, 2024 | Award | +110,000 | – | – | 110,000 |
| Peter J. Mariani Chief Financial Officer | Aug 14, 2024 | Award | +65,000 | – | – | 175,000 |
| Peter J. Mariani Chief Financial Officer | Aug 14, 2024 | Award | +175,000 | – | – | 350,000 |
| Vincent Capponi President and COO | Apr 2, 2024 | Award | +81,000 | – | – | 665,134 |
| Efthymios Deliargyris Chief Medical Officer | Apr 2, 2024 | Award | +61,000 | – | – | 409,433 |
| Phillip P. Chan Chief Executive Officer, Director | Apr 2, 2024 | Award | +96,000 | – | – | 1,164,704 |
| Kathleen P. Bloch Chief Financial Officer | Apr 2, 2024 | Award | +65,000 | – | – | 532,941 |
| Vincent Capponi President & COO | Dec 13, 2023 | Buy | +18,797 | $1.33 | $25.00K | 584,134 |
| Kathleen P. Bloch Chief Financial Officer | Dec 13, 2023 | Buy | +37,594 | $1.33 | $50.00K | 467,941 |
| Edward Raymond Jones Director | Dec 13, 2023 | Buy | +7,519 | $1.33 | $10.00K | 88,834 |
| Jiny Kim Director | Dec 13, 2023 | Buy | +7,519 | $1.33 | $10.00K | 77,819 |
| Michael G. Bator Director | Dec 13, 2023 | Buy | +37,594 | $1.33 | $50.00K | 125,394 |
| Phillip P. Chan Chief Executive Officer, Director | Dec 13, 2023 | Buy | +75,188 | $1.33 | $100.00K | 1,068,704 |
| Efthymios Deliargyris Chief Medical Officer | Dec 13, 2023 | Buy | +22,557 | $1.33 | $30.00K | 348,433 |
| Alan D. Sobel Director | Dec 13, 2023 | Buy | +22,557 | $1.33 | $30.00K | 101,857 |
| Kathleen P. Bloch Chief Financial Officer | Sep 18, 2023 | Award | +45,000 | – | – | 442,347 |
| Michael G. Bator Director | Aug 7, 2023 | Buy | +1,000 | $3.20 | $3.20K | 86,800 |
| Michael G. Bator Director | Aug 7, 2023 | Buy | +1,000 | $3.15 | $3.15K | 87,800 |
| Michael G. Bator Director | Aug 4, 2023 | Buy | +1,000 | $3.23 | $3.23K | 85,800 |
| Phillip P. Chan Chief Executive Officer, Director | Jul 7, 2023 | Award | +87,000 | – | – | 1,006,548 |
| Efthymios Deliargyris Chief Medical Officer | Jul 7, 2023 | Award | +55,000 | – | – | 331,648 |
| Vincent Capponi President & COO | Jul 7, 2023 | Award | +73,000 | – | – | 576,153 |
| Kathleen P. Bloch Interim CFO | May 25, 2023 | Buy | +1,100 | $2.85 | $3.14K | 47,000 |
| Kathleen P. Bloch Interim CFO | May 25, 2023 | Buy | +1,100 | $2.84 | $3.12K | 45,900 |
| Kathleen P. Bloch Interim CFO | May 25, 2023 | Buy | +1,100 | $2.85 | $3.14K | 44,800 |
| Kathleen P. Bloch Interim CFO | May 10, 2023 | Buy | +2,000 | $3.13 | $6.26K | 40,700 |
| Kathleen P. Bloch Interim CFO | May 10, 2023 | Buy | +3,000 | $3.17 | $9.51K | 43,700 |
| Kathleen P. Bloch Interim CFO | May 10, 2023 | Buy | +5,000 | $3.06 | $15.30K | 38,700 |
| Vincent Capponi See Remarks | Apr 4, 2023 | Option exercise | +10,000 | $2.88 | $28.80K | 511,989 |
| Phillip P. Chan Chief Executive Officer | Apr 3, 2023 | Option exercise | +30,500 | $2.88 | $87.84K | 927,779 |
| Alan D. Sobel Director | Feb 27, 2023 | Gift | +2,000 | – | – | 81,300 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Short interest
Shares sold short and not yet bought back, as of Oct 30, 2026 (FINRA, reported twice a month)
Short % of float
0.22%
0M shares short
Days to cover
1.1
At 0M shares a day
Change since last report
+17.9%
From 0M shares
Short volume, 20 days
39.5%
Of volume reported to FINRA
Shares sold short, last 12 months
Short sale volume counts trades marked short on any given day, including market-maker hedging, so it runs far higher than the share of Cytosorbents's stock actually held short. Settlement fails (shares not delivered on time) peaked at 4,859 shares on Sep 14, 2026 over the last 90 days.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| Peter J. Mariani Officer | Aug 19, 2025 | 10,548 | $11.45K | Aug 19, 2025 | Restricted Stock Vesting |
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