Cytosorbents (CTSO) CFO Peter Mariani buys 100,000 shares in open market

Filing Impact

(Neutral)

Filing Sentiment

(Positive)

Form Type

Rhea-AI Filing Summary

Cytosorbents Corp Chief Financial Officer Peter J. Mariani reported an open-market purchase of 100,000 shares of Common Stock at a weighted average price of $0.44 per share on June 15, 2026. Following this transaction, he directly holds 638,113 shares, which include a mix of common shares and restricted stock units that vest over time or upon a defined change in control, subject to his continued service.

Insights

CFO made a sizable open-market share purchase and increased his direct stake.

The filing shows Cytosorbents Corp CFO Peter J. Mariani bought 100,000 Common Stock shares in an open-market transaction at a weighted average price of $0.44 per share. This is a discretionary purchase coded as an open-market transaction.

After the trade, his direct holdings total 638,113 shares, combining common stock with several tranches of restricted stock units (RSUs) that vest based on time or a Change In Control as defined in his employment agreement. No derivative exercises or sales appear in this filing.

The footnotes explain that the shares were bought in multiple trades between $0.40 and $0.45, and detail the RSU structure, including awards that vest through August 14, 2028 or upon a change in control. Subsequent filings may update how these RSUs vest over time.

Insider Trade Summary

Net Buyer: 100,000 shares ($44,000)

Net Buy 1 txn

Insider MARIANI PETER J

Role Chief Financial Officer

Bought 100,000 shs ($44K)

Type	Security	Shares	Price	Value
Purchase	Common Stock	100,000	$0.44	$44K

Holdings After Transaction: Common Stock — 638,113 shares (Direct, null)

Footnotes (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 $0.40 to $0.45, 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 this footnote (1) to this Form 4. Includes (a) 110,000 restricted stock units ("RSUs"), which will be settled into the Issuer's common stock, par value $0.001 per share (the "Common Stock"), upon vesting upon the earlier of (i) a "Change In Control" of the Issuer, as defined in the Reporting Person's employment agreement (the "Employment Agreement"), or (ii) the fourth anniversary from the date of grant, or August 14, 2028, subject to the Reporting Person's continued service as of the applicable vesting date; (continued from footnote 2) (b) 65,000 RSUs, of which 32,500 remain unvested as of the date hereof, and which shall vest as to one-half of the award on each of the first and second anniversaries of the date of grant, subject to the Reporting Person's continued service as of the applicable vesting date and will be settled into Common Stock upon vesting; (continued from footnote 3) (c) 175,000 RSUs, which will be settled into Common Stock upon a "Change In Control" of the Issuer, as defined in the Reporting Person's Employment Agreement, subject to the Reporting Person's continued service as of the applicable vesting date; (d) 71,500 RSUs, which shall vest as to one-half of the award on each of the first and second anniversaries of the date of grant, subject to the Reporting Person's continued service as of the applicable vesting date and will be settled into Common Stock upon vesting; and (continued from footnote 4) (e) 216,613 shares of Common Stock owned by the Reporting Person.

Key Figures

Shares purchased: 100,000 shares Purchase price: $0.44 per share Shares after transaction: 638,113 shares +4 more

7 metrics

Shares purchased 100,000 shares Open-market purchase on June 15, 2026

Purchase price $0.44 per share Weighted average price across multiple trades

Shares after transaction 638,113 shares Total direct holdings following the purchase

RSU grant A 110,000 RSUs Vests by August 14, 2028 or upon Change In Control

RSU grant B unvested portion 32,500 RSUs Remain unvested from a 65,000-unit award

RSU grant C 175,000 RSUs Settle into Common Stock upon Change In Control

Common Stock owned 216,613 shares Common Stock directly owned by the reporting person

Key Terms

open market purchase, weighted average price, restricted stock units ("RSUs"), Change In Control, +1 more

5 terms

open market purchase financial

"The transaction reported on this Form 4 reflects an open market purchase made by the Reporting Person."

An open market purchase is when a company buys its own shares on public stock exchanges the same way any investor would, rather than through a private deal. Investors care because these purchases reduce the number of shares available, can boost earnings per share and share price, signal that management thinks the stock is undervalued, and use company cash that might otherwise go to reinvestment or dividends — like a business quietly buying back its own tickets at the box office.

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.

restricted stock units ("RSUs") financial

"Includes (a) 110,000 restricted stock units ("RSUs"), which will be settled into the Issuer's common stock..."

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

"upon the earlier of (i) a "Change In Control" of the Issuer, as defined in the Reporting Person's employment agreement..."

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.

employment agreement financial

"as defined in the Reporting Person's employment agreement (the "Employment Agreement")"

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Form 4 Insider Transactions: What Each Field Means →

06/16/2026 - 07:00 AM

SEC Form 4

FORM 4

UNITED 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^*

MARIANI PETER J

(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)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Chief Financial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/15/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form 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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	06/15/2026		P		100,000⁽¹⁾	A	$0.44	638,113⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

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 $0.40 to $0.45, 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 this footnote (1) to this Form 4.

2. Includes (a) 110,000 restricted stock units ("RSUs"), which will be settled into the Issuer's common stock, par value $0.001 per share (the "Common Stock"), upon vesting upon the earlier of (i) a "Change In Control" of the Issuer, as defined in the Reporting Person's employment agreement (the "Employment Agreement"), or (ii) the fourth anniversary from the date of grant, or August 14, 2028, subject to the Reporting Person's continued service as of the applicable vesting date;

3. (continued from footnote 2) (b) 65,000 RSUs, of which 32,500 remain unvested as of the date hereof, and which shall vest as to one-half of the award on each of the first and second anniversaries of the date of grant, subject to the Reporting Person's continued service as of the applicable vesting date and will be settled into Common Stock upon vesting;

4. (continued from footnote 3) (c) 175,000 RSUs, which will be settled into Common Stock upon a "Change In Control" of the Issuer, as defined in the Reporting Person's Employment Agreement, subject to the Reporting Person's continued service as of the applicable vesting date; (d) 71,500 RSUs, which shall vest as to one-half of the award on each of the first and second anniversaries of the date of grant, subject to the Reporting Person's continued service as of the applicable vesting date and will be settled into Common Stock upon vesting; and

5. (continued from footnote 4) (e) 216,613 shares of Common Stock owned by the Reporting Person.

	/s/ Peter J. Mariani	06/16/2026
	** Signature of Reporting Person	Date
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 transaction did Cytosorbents (CTSO) report for CFO Peter J. Mariani?

Cytosorbents reported that CFO Peter J. Mariani bought 100,000 Common Stock shares. He made an open-market purchase at a weighted average price of $0.44 per share, increasing his direct holdings to 638,113 shares after the transaction, according to the Form 4 filing.

At what price did the Cytosorbents (CTSO) CFO buy his shares?

The CFO’s shares were purchased at a weighted average price of $0.44. The filing notes multiple trades between $0.40 and $0.45 per share, with $0.44 reported as the average price in Column 4, reflecting the overall cost of the 100,000-share purchase.

How many Cytosorbents (CTSO) shares does the CFO hold after this Form 4 transaction?

After the transaction, the CFO directly holds 638,113 Cytosorbents shares. This total includes common stock and several restricted stock unit grants that will settle into common shares over time or upon specific conditions such as a defined change in control event.

What restricted stock units (RSUs) are included in the Cytosorbents (CTSO) CFO’s holdings?

The CFO’s position includes multiple RSU grants with different vesting conditions. Footnotes describe 110,000 RSUs vesting by August 14, 2028 or upon a change in control, plus additional RSU awards with time-based vesting and a separate 175,000-unit grant tied to a change in control.

Was the Cytosorbents (CTSO) CFO’s Form 4 transaction a market purchase or another type of acquisition?

The Form 4 identifies the transaction as an open-market purchase. It is coded as a “P” transaction with the description “Purchase in open market or private transaction,” confirming that the CFO bought 100,000 Common Stock shares rather than receiving them as a grant or via option exercise.