Trinseo (TSE) CEO logs tax-withholding share disposition on RSU vest

Rhea-AI Filing Summary

Trinseo PLC CEO and president Frank A. Bozich reported a tax-related share disposition tied to equity compensation. On this Form 4, the company withheld 32,602 Ordinary Shares at $0.3276 per share to cover taxes due upon vesting of restricted stock units. After this withholding, Bozich’s directly held stake is shown as 688,369 Ordinary Shares, and the filing characterizes the event as a tax-withholding disposition rather than an open-market trade.

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

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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^*

BOZICH FRANK A

(Last) (First) (Middle)

C/O TRINSEO PLC

440 EAST SWEDESFORD ROAD, SUITE 301

(Street)

WAYNE PA 19087

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Trinseo PLC [ TSE ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

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

3. Date of Earliest Transaction (Month/Day/Year)
02/22/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

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

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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
Ordinary Shares	02/22/2026		F		32,602(1)	D	$0.3276	688,369	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. Shares withheld by the Company to pay taxes due following the vesting of restricted stock units.

	/s/ Angelo Chaclas, Attorney-in-Fact	02/24/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did Trinseo (TSE) report for CEO Frank Bozich?

Trinseo reported a tax-withholding disposition for CEO Frank Bozich. The company withheld 32,602 Ordinary Shares to cover taxes due on vesting restricted stock units, rather than Bozich selling shares in an open-market transaction.

How many Trinseo (TSE) shares were withheld for CEO tax obligations?

The filing shows 32,602 Ordinary Shares were withheld to satisfy tax obligations. These shares were retained by the company following the vesting of restricted stock units, consistent with a Form 4 code F tax-withholding disposition.

At what price per share were Trinseo (TSE) shares valued for the tax withholding?

The withheld shares were valued at $0.3276 per Ordinary Share. This price is used solely for the tax-withholding calculation related to vested restricted stock units, not as an open-market sale price or broader valuation signal.

How many Trinseo (TSE) shares does CEO Frank Bozich hold after this Form 4?

After the tax-withholding disposition, Frank Bozich directly holds 688,369 Ordinary Shares. This post-transaction balance reflects the shares remaining in his direct ownership after 32,602 shares were withheld by the company for tax purposes.

Does the Trinseo (TSE) Form 4 indicate an open-market sale by the CEO?

No, the Form 4 reflects a tax-withholding disposition, not an open-market sale. Shares were withheld by the company to pay taxes after restricted stock units vested, which is a common administrative step in equity compensation programs.