Cytosorbents director buys 2,500 shares at $6.12

A Cytosorbents Corp director made open-market purchases totaling 2,500 shares at around $6 per share, outside any Rule 10b5-1 trading plan.

Rhea-AI Filing Summary

Cytosorbents Corp (CTSO) director Alan D. Sobel reported open-market purchases of company common stock on September 15, 2026. He bought a total of 2,500 shares in three transactions at prices between $6.01 and $6.12 per share. No Rule 10b5-1 trading plan is reported for these purchases. His equity interests also include restricted stock units that vest upon a Change in Control under the company’s 2014 Long-Term Incentive Plan and 6,422 shares of common stock owned directly, all reflecting a previously effected 1-for-20 reverse stock split.

Insider Trade Summary

Net Buyer: 2,500 shares

Net Buy 3 txns

Insider Sobel Alan D.

Role Director

Bought 2,500 shs ($15K)

Type	Security	Shares	Price	Value
Purchase	Common Stock F1, F2, F3	1,900	$6.12	$12K
Purchase	Common Stock F1, F2, F3	500	$6.05	$3K
Purchase	Common Stock F1, F2, F3	100	$6.01	$601.00

Holdings After Transaction: Common Stock — 9,887 shares (Direct)

Footnotes (3)

1. F1. These transactions reported on this Form 4 reflect open market purchases made by the Reporting Person.
2. F2. Includes (i) the following restricted stock units ("RSUs") that will be settled into Common Stock upon vesting upon a "Change in Control" of CytoSorbents Corporation (the "Issuer"), as defined in the CytoSorbents Corporation 2014 Long-Term Incentive Plan (the "Plan"): (a) 165 RSUs granted on March 15, 2018, (b) 300 RSUs granted on February 24, 2017, (c) 250 RSUs granted on June 7, 2016, and (d) 2,750 RSUs granted on April 8, 2015 and (ii) 6,422 shares of Common Stock owned directly by the Reporting Person.
3. F3. Reflects the 1-for-20 reverse stock split effected by the Issuer on September 8, 2026.

Key Figures

Shares purchased (total): 2,500 shares Shares purchased at $6.12: 1,900 shares Shares purchased at $6.05: 500 shares +4 more

7 metrics

Shares purchased (total) 2,500 shares Open-market purchases of Cytosorbents Corp common stock on September 15, 2026

Shares purchased at $6.12 1,900 shares Open-market purchase on September 15, 2026

Shares purchased at $6.05 500 shares Open-market purchase on September 15, 2026

Shares purchased at $6.01 100 shares Open-market purchase on September 15, 2026

Restricted Stock Units (RSUs) 3,465 RSUs RSUs that settle into common stock upon a Change in Control, from 2015–2018 grants

Common shares owned directly 6,422 shares Common stock owned directly by the reporting person, post reverse split

Reverse stock split ratio 1-for-20 Reverse stock split effected by Cytosorbents Corp on September 8, 2026

Key Terms

restricted stock units, Change in Control, Long-Term Incentive Plan, reverse stock split

4 terms

restricted stock units financial

"Includes (i) the following restricted stock units ("RSUs") that will be settled into Common Stock"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Change in Control financial

"RSUs that will be settled into Common Stock upon vesting upon a "Change in Control" of CytoSorbents"

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.

Long-Term Incentive Plan financial

"as defined in the CytoSorbents Corporation 2014 Long-Term Incentive Plan (the "Plan")"

A long-term incentive plan is a company program that pays executives or employees with stock, options, or cash tied to multi-year performance goals, where the rewards become theirs only after meeting conditions over time. Think of it as a delayed bonus or retirement-style reward that aligns employees’ interests with shareholders by encouraging them to boost long-term value; investors watch these plans because they affect pay costs, share dilution and management incentives.

reverse stock split financial

"Reflects the 1-for-20 reverse stock split effected by the Issuer on September 8, 2026"

A reverse stock split reduces a company's number of outstanding shares while raising the price per share proportionally, so the total value of each investor's holding is unchanged; a 1-for-10 split turns 100 shares worth $1 each into 10 shares worth $10 each. Companies often do this to regain compliance with an exchange's minimum price rule or to attract investors who avoid very low-priced stocks.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did CTSO director Alan D. Sobel report?

Alan D. Sobel reported open-market purchases of Cytosorbents Corp common stock totaling 2,500 shares on September 15, 2026, in three separate transactions, as disclosed in the Form 4.

At what prices were the CTSO shares purchased in this Form 4?

The reported Cytosorbents Corp share purchases were made at prices of $6.12, $6.05, and $6.01 per share, each described as a purchase in an open market or private transaction.

How many Cytosorbents (CTSO) shares did the director buy in each trade?

On September 15, 2026, the director bought 1,900 shares at $6.12, 500 shares at $6.05, and 100 shares at $6.01 of Cytosorbents Corp common stock, for a total of 2,500 shares.

Were the CTSO insider purchases made under a Rule 10b5-1 trading plan?

No. The filing’s Rule 10b5-1 checkbox is not marked as affirming a plan, and a footnote states these Form 4 transactions reflect open market purchases by the reporting person.

What other CTSO equity does the director hold according to the Form 4?

The Form 4 notes the director holds RSUs that settle into common stock upon a Change in Control (165, 300, 250, and 2,750 RSUs from grants in 2015–2018) and 6,422 shares of Cytosorbents common stock owned directly, all adjusted for the 1-for-20 reverse split.

What reverse stock split of CTSO is referenced in the Form 4?

A footnote states the holdings reflect a 1-for-20 reverse stock split effected by Cytosorbents Corp on September 8, 2026, meaning every 20 pre-split shares became 1 post-split share.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/16/2026 - 04:06 PM Accepted by SEC EDGAR 09/16/2026 - 04:05 PM Learn about SEC filing dates

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^*

Sobel Alan D.

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/15/2026

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/15/2026		P		1,900	A	$6.12	9,287(1)(2)(3)	D
Common Stock	09/15/2026		P		500	A	$6.05	9,787(1)(2)(3)	D
Common Stock	09/15/2026		P		100	A	$6.01	9,887(1)(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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. These transactions reported on this Form 4 reflect open market purchases made by the Reporting Person.

2. Includes (i) the following restricted stock units ("RSUs") that will be settled into Common Stock upon vesting upon a "Change in Control" of CytoSorbents Corporation (the "Issuer"), as defined in the CytoSorbents Corporation 2014 Long-Term Incentive Plan (the "Plan"): (a) 165 RSUs granted on March 15, 2018, (b) 300 RSUs granted on February 24, 2017, (c) 250 RSUs granted on June 7, 2016, and (d) 2,750 RSUs granted on April 8, 2015 and (ii) 6,422 shares of Common Stock owned directly by the Reporting Person.

3. Reflects the 1-for-20 reverse stock split effected by the Issuer on September 8, 2026.

	/s/ Peter J. Mariani attorney-in-fact Alan D. Sobel	09/16/2026
	** 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)