Trinseo (TSE) SVP Schewe reports tax-withholding share disposition

Rhea-AI Filing Summary

Trinseo PLC senior vice president of supply chain and manufacturing services Rainer Schewe reported a tax-related share disposition. On February 27, 4,028 ordinary shares were withheld by the company at a price of $0.23 per share to cover taxes on vesting restricted stock units. After this withholding, Schewe directly owned 103,415 ordinary shares.

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^*

Schewe Rainer

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	SVP, SUPPLY CHAIN & MFG SVCS

3. Date of Earliest Transaction (Month/Day/Year)
02/27/2026

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	02/27/2026		F		4,028(1)	D	$0.23	103,415	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 previously granted restricted stock units.

	/s/ Angelo Chaclas, Attorney-in-Fact	03/03/2026
	** 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).
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FAQ

What insider transaction did Trinseo (TSE) report for Rainer Schewe?

Trinseo reported a tax-related share disposition for Rainer Schewe. The company withheld 4,028 ordinary shares to cover taxes due when previously granted restricted stock units vested, rather than Schewe selling shares in the open market.

How many Trinseo (TSE) shares were withheld for Rainer Schewes taxes?

A total of 4,028 Trinseo ordinary shares were withheld for taxes. These shares covered the tax liability arising from the vesting of earlier restricted stock unit awards granted to Rainer Schewe, according to the Form 4 footnote disclosure.

At what price were Rainer Schewes Trinseo (TSE) shares withheld for taxes?

The shares withheld for Rainer Schewes taxes were valued at $0.23 per Trinseo ordinary share. This price is used solely for reporting the tax-withholding disposition associated with the vesting of restricted stock units, not an open-market sale price.

How many Trinseo (TSE) shares does Rainer Schewe own after the tax withholding?

After the tax-withholding transaction, Rainer Schewe directly owned 103,415 Trinseo ordinary shares. This figure reflects his reported direct beneficial ownership following the 4,028 shares withheld by the company to satisfy the related tax obligation.

Was Rainer Schewes Trinseo (TSE) Form 4 transaction an open-market sale?

The transaction was not an open-market sale. Shares were withheld by Trinseo to pay taxes owed when restricted stock units vested, classified as a tax-withholding disposition rather than Schewe choosing to sell shares on the open market.

What role does Rainer Schewe hold at Trinseo (TSE) in this Form 4?

In this Form 4, Rainer Schewe is identified as an officer of Trinseo, serving as senior vice president for supply chain and manufacturing services. The reported transaction relates to his equity compensation and associated tax obligations.