Cytosorbents Corporation (CTSO) Ownership
CTSO ownership summary
as of October 18, 2026- Institutions
- 25.5% of shares outstanding
- Insiders
- 16.25% of shares outstanding
- Shares outstanding
- 3.2M
- Float
- 2.8M shares available to trade
- Short interest
- 4.27% 124K shares short
- Days to cover
- 4.71 short interest up 2.7% vs prior month
- Institutions 25.50%
- Insiders 16.25%
- Other investors 58.24%
CTSO top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Avenir Corporation | 8.23% | 5.2M | $21.3M | −26,558 (−0.5%) | June 30, 2026 |
| 2 | Neuberger Berman Group LLC | 3.12% | 2.0M | $8.1M | +285,684 (+17.0%) | June 30, 2026 |
| 3 | Vanguard Capital Management, LLC | 3.04% | 1.9M | $7.9M | +34,074 (+1.8%) | June 30, 2026 |
| 4 | CM Management, LLC | 2.34% | 1.5M | $6.1M | — | June 30, 2026 |
| 5 | Skylands Capital, LLC | 1.92% | 1.2M | $5.0M | −496,098 (−29.1%) | June 30, 2026 |
| 6 | BlackRock Inc | 1.00% | 627K | $2.6M | −155,781 (−19.9%) | June 30, 2026 |
| 7 | Geode Capital Management, LLC | 0.96% | 602K | $2.5M | −105,203 (−14.9%) | June 30, 2026 |
| 8 | Sargent Investment Group, LLC | 0.88% | 556K | $2.3M | +5,857 (+1.1%) | June 30, 2026 |
| 9 | Pathstone Holdings LLC | 0.79% | 500K | $2.1M | −45 (−0.0%) | June 30, 2026 |
| 10 | Vanguard Fiduciary Trust Co | 0.50% | 316K | $1.3M | +2,311 (+0.7%) | June 30, 2026 |
| 11 | CIBC Bancorp USA Inc. | 0.27% | 173K | $709,587 | — | June 30, 2026 |
| 12 | State Street Corp | 0.25% | 159K | $654,694 | — | June 30, 2026 |
| 13 | Advisor Group Holdings, Inc. | 0.21% | 135K | $554,188 | +4,420 (+3.4%) | June 30, 2026 |
| 14 | UBS Group AG | 0.21% | 131K | $538,488 | +15,819 (+13.7%) | June 30, 2026 |
| 15 | Northern Trust Corp | 0.18% | 112K | $458,923 | +19,120 (+20.7%) | June 30, 2026 |
| 16 | Nwf Advisory Services Inc | 0.17% | 104K | $428,011 | — | June 30, 2026 |
| 17 | Renaissance Technologies Corp | 0.16% | 100K | $411,082 | −700 (−0.7%) | June 30, 2026 |
| 18 | Morgan Stanley - Brokerage Accounts | 0.14% | 91K | $375,399 | −8,831 (−8.8%) | June 30, 2026 |
| 19 | Key Client Fiduciary Advisors, LLC | 0.12% | 78K | $322,458 | — | June 30, 2026 |
| 20 | Virtu Financial LLC | 0.11% | 72K | $293,898 | +71,508 (0.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 8 holders added 439K shares and 7 cut 793K.
CTSO top mutual fund and ETF holders
14 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 2.02% | 1.3M | $5.2M | — | August 31, 2026 |
| 2 | Fidelity Extended Market Index | 0.46% | 291K | $1.2M | −1,562 (−0.5%) | August 31, 2026 |
| 3 | Fidelity Total Market Index | 0.15% | 94K | $387,651 | — | August 31, 2026 |
| 4 | Neuberger US Sm Cp Intrs Val USD I Acc | 0.14% | 89K | $364,430 | — | June 30, 2026 |
| 5 | Fidelity Series Total Market Index | 0.12% | 79K | $322,964 | — | August 31, 2026 |
| 6 | Vanguard Balanced Index Inv | 0.06% | 36K | $146,485 | — | August 31, 2026 |
| 7 | Neuberger Intrinsic Value I | 1.03% | 32K | $132,856 | −1 (−0.0%) | September 30, 2026 |
| 8 | Vanguard MStar Inst Ttl StkMktIdxInstlPl | 0.05% | 30K | $121,640 | — | August 31, 2026 |
| 9 | Fidelity Nasdaq Composite Index | 0.04% | 22K | $91,419 | — | August 31, 2026 |
| 10 | Vanguard U.S. Eq Idx £ Acc | 0.02% | 14K | $56,985 | — | August 31, 2026 |
| 11 | Morgan Stanley Pathway Sm-Md Cp Eq ETF | 0.03% | 1,031 | $4,237 | — | September 30, 2026 |
| 12 | Guggenheim Active Allocation Fund | <0.01% | 490 | $2,014 | +245 (+100.0%) | May 31, 2026 |
| 13 | Column Small Cap Select | 0.01% | 338 | $1,389 | +1 (+0.3%) | September 30, 2026 |
| 14 | Column Small Cap | <0.01% | 91 | $374 | — | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
CTSO insider transactions
latest 7| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2024-12-13 | Peter J Mariani | Buy | $0.96 | 20,000 | $19,200 |
| 2024-12-11 | Peter J Mariani | Buy | $0.89 | 11,363 | $10,113 |
| 2023-12-13 | Alan D Sobel | Buy | $1.33 | 22,557 | $30,001 |
| 2023-08-07 | Michael G Bator | Buy | $3.17 | 2,000 | $6,340 |
| 2023-08-04 | Michael G Bator | Buy | $3.23 | 1,000 | $3,230 |
| 2023-05-25 | Kathleen P Bloch | Buy | $2.85 | 3,300 | $9,405 |
| 2023-05-10 | Kathleen P Bloch | Buy | $3.11 | 10,000 | $31,100 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
CTSO shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns CTSO
Institutional investors own 25.5% of Cytosorbents's shares and insiders 16.25%. The largest holder is Avenir Corporation with 8.23% of the shares (5.2M), as of June 30, 2026. Among the top 20 institutions, 8 added shares and 7 reduced their stake in the latest filings. Short interest is 4.27% of the float, or 4.71 days of average trading volume. The share count rose 157.5% since 2014.
Related: CTSO analyst forecast, CTSO key metrics. See the CTSO stock overview for the latest quote and news.
CTSO ownership FAQ
Who owns the most Cytosorbents stock?
The largest shareholders of Cytosorbents are Avenir Corporation (8.23%), Neuberger Berman Group LLC (3.12%), Vanguard Capital Management, LLC (3.04%), CM Management, LLC (2.34%), Skylands Capital, LLC (1.92%).
What percentage of Cytosorbents is owned by institutions?
Institutions hold 25.5% of Cytosorbents's shares outstanding; insiders hold 16.25%.
Which funds own Cytosorbents?
The largest fund holders of Cytosorbents are Vanguard MStar Total Stk Mkt Idx Invest (2.02%), Fidelity Extended Market Index (0.46%), Fidelity Total Market Index (0.15%), Neuberger US Sm Cp Intrs Val USD I Acc (0.14%), Fidelity Series Total Market Index (0.12%).
What is Cytosorbents's short interest?
124K shares of Cytosorbents were sold short, 4.27% of the float; at the average daily volume it would take 4.71 days to cover.
Are insiders buying or selling Cytosorbents?
Of the latest 7 reported insider transactions in Cytosorbents (since May 10, 2023), 7 were purchases and 0 were sales.
How many shares of Cytosorbents are outstanding?
Cytosorbents has 3.2M shares outstanding, of which 2.8M are in the public float.