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Cytosorbents (CTSO) CEO boosts stake with 261,469-share open-market buy

Filing Impact
(High)
Filing Sentiment
(Positive)
Form Type
4

Rhea-AI Filing Summary

Cytosorbents Corp CEO Phillip P. Chan reported open-market purchases of company common stock. On June 12, 2026, he bought 251,136 shares at a weighted average price of $0.40 per share. On June 15, 2026, he bought another 10,333 shares at a weighted average price of $0.43 per share.

Following these transactions, Chan directly holds 1,744,432 shares reported as common stock, a figure that includes several grants of restricted stock units that vest upon a Change In Control or over time, plus 1,422,832 shares of currently owned common stock.

Positive

  • None.

Negative

  • None.
Insider Chan Phillip P.
Role Chief Executive Officer
Bought 261,469 shs ($105K)
Type Security Shares Price Value
Purchase Common Stock 10,333 $0.43 $4K
Purchase Common Stock 251,136 $0.40 $100K
Holdings After Transaction: Common Stock — 1,744,432 shares (Direct, null)
Footnotes (1)
  1. The transaction reported on this Form 4 reflects an open market purchase made by the Reporting Person. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.3885 to $0.40, inclusive. The Reporting Person undertakes to provide to CytoSorbents Corporation (the "Issuer"), any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (1) and (4) to this Form 4. Includes: (i) the following restricted stock units ("RSUs") that will be settled into shares of Common Stock upon vesting upon a "Change In Control" of the Company as defined in the Amended and Restated CytoSorbents Corporation 2014 Long-Term Incentive Plan (the "Plan"): (a) 10,300 RSUs granted on March 15, 2018, (b) 18,700 RSUs granted on February 24, 2017, (c) 57,000 RSUs granted on June 7, 2016 and (d) 130,000 RSUs granted on April 8, 2015; (continued from footnote 2) (iii) 105,600 RSUs granted on August 8, 2025, which shall vest in equal parts at the first and second year anniversaries of the date of grant, subject to the Reporting Person's continued service as of the applicable vesting date, and (iv) 1,422,832 shares of Common Stock owned by the Reporting Person. The transaction reported on this Form 4 reflects an open market purchase made by the reporting person. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.4307 to $0.4388, inclusive.
Total shares bought 261,469 shares Open-market purchases on June 12 and 15, 2026
June 12 purchase size 251,136 shares at $0.40/share Common Stock, weighted average price
June 15 purchase size 10,333 shares at $0.43/share Common Stock, weighted average price
Post-transaction holdings 1,744,432 shares Total common stock reported following transactions
Common shares owned 1,422,832 shares Shares of Common Stock owned by the reporting person
Largest RSU grant 130,000 RSUs Granted April 8, 2015, settles upon Change In Control
Recent RSU grant 105,600 RSUs Granted August 8, 2025, vests over two years
restricted stock units ("RSUs") financial
"Includes: (i) the following restricted stock units ("RSUs") that will be settled into shares of Common Stock upon vesting..."
Restricted stock units (RSUs) are a company promise to give an employee shares of stock (or cash equivalent) in the future, but only after certain conditions—usually staying with the company for a set time or hitting performance goals—are met. Investors watch RSUs because when they vest they increase the number of shares outstanding and can lead insiders to sell shares, affecting share price, company dilution and the true cost of employee pay.
Change In Control financial
"RSUs that will be settled into shares of Common Stock upon vesting upon a "Change In Control" of the Company..."
A "change in control" occurs when the ownership or management of a company shifts significantly, such as through a merger, acquisition, or sale of a large part of its assets. This change can impact how the company is run and may influence its future direction. For investors, it matters because it can affect the company's stability, strategy, and value, often signaling potential changes in investment risk or opportunity.
Amended and Restated CytoSorbents Corporation 2014 Long-Term Incentive Plan financial
"...as defined in the Amended and Restated CytoSorbents Corporation 2014 Long-Term Incentive Plan (the "Plan")"
weighted average price financial
"The price reported in Column 4 is a weighted average price."
Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.
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Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Chan Phillip P.
(Last)(First)(Middle)
C/O CYTOSORBENTS CORPORATION
305 COLLEGE ROAD EAST
(Street)
PRINCETON NEW JERSEY 08540
(City)(State)(Zip)
UNITED STATES
(Country)		2. Issuer Name and Ticker or Trading Symbol
Cytosorbents Corp [ CTSO ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
Chief Executive Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/12/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Common Stock06/12/2026P251,136(1)A$0.41,734,099(2)(3)D
Common Stock06/15/2026P10,333(4)A$0.431,744,432(2)(3)D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. The transaction reported on this Form 4 reflects an open market purchase made by the Reporting Person. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.3885 to $0.40, inclusive. The Reporting Person undertakes to provide to CytoSorbents Corporation (the "Issuer"), any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (1) and (4) to this Form 4.
2. Includes: (i) the following restricted stock units ("RSUs") that will be settled into shares of Common Stock upon vesting upon a "Change In Control" of the Company as defined in the Amended and Restated CytoSorbents Corporation 2014 Long-Term Incentive Plan (the "Plan"): (a) 10,300 RSUs granted on March 15, 2018, (b) 18,700 RSUs granted on February 24, 2017, (c) 57,000 RSUs granted on June 7, 2016 and (d) 130,000 RSUs granted on April 8, 2015;
3. (continued from footnote 2) (iii) 105,600 RSUs granted on August 8, 2025, which shall vest in equal parts at the first and second year anniversaries of the date of grant, subject to the Reporting Person's continued service as of the applicable vesting date, and (iv) 1,422,832 shares of Common Stock owned by the Reporting Person.
4. The transaction reported on this Form 4 reflects an open market purchase made by the reporting person. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.4307 to $0.4388, inclusive.
/s/ Phillip P. Chan06/15/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider stock purchases did Cytosorbents (CTSO) CEO Phillip Chan report?

Cytosorbents CEO Phillip Chan reported buying 261,469 CTSO shares in the open market. He acquired 251,136 shares at $0.40 on June 12, 2026 and 10,333 shares at $0.43 on June 15, 2026, increasing his direct holdings.

At what prices did the Cytosorbents (CTSO) CEO buy recent shares?

Phillip Chan bought Cytosorbents common stock at weighted average prices of $0.40 and $0.43 per share. The June 12, 2026 purchase averaged $0.40 across multiple trades, while the June 15, 2026 purchase averaged $0.43 within a reported price range.

How many Cytosorbents (CTSO) shares does the CEO hold after these transactions?

After the June 2026 purchases, CEO Phillip Chan is reported holding 1,744,432 shares of Cytosorbents common stock. This figure includes multiple restricted stock unit awards and 1,422,832 currently owned common shares, providing significant direct equity exposure to the company.

What are the recent RSU grants reported for the Cytosorbents (CTSO) CEO?

Phillip Chan’s holdings include several restricted stock unit (RSU) grants, such as 130,000 RSUs from April 8, 2015 and 105,600 RSUs from August 8, 2025. Some RSUs vest upon a Change In Control, others vest over time with continued service.

Were the Cytosorbents (CTSO) CEO share purchases single trades or multiple transactions?

Both reported purchases were executed as multiple transactions at different prices. For example, June 12, 2026 trades ranged from $0.3885 to $0.40, and June 15, 2026 trades ranged from $0.4307 to $0.4388, disclosed as weighted average prices.