Trinseo (TSE) SVP reports 7,670-share tax-withholding disposition

Rhea-AI Filing Summary

Trinseo PLC executive reports routine tax-related share disposition. SVP and CHRO Paula M. Cooney had 7,670 Ordinary Shares withheld by the company at a price of $0.23 per share to cover taxes due on vested restricted stock units. After this tax-withholding event, she directly owned 118,318 Ordinary Shares.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Cooney Paula M.

Role SVP, CHRO

Type	Security	Shares	Price	Value
Tax Withholding	Ordinary Shares	7,670	$0.23	$2K

Holdings After Transaction: Ordinary Shares — 118,318 shares (Direct)

Footnotes (1)

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Form 4 Insider Transactions: What Each Field Means →

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^*

Cooney Paula M.

(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, CHRO

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		7,670(1)	D	$0.23	118,318	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	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).
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.

FAQ

What insider transaction did Trinseo (TSE) report for Paula M. Cooney?

Trinseo reported that SVP and CHRO Paula M. Cooney had shares withheld for taxes. The company withheld 7,670 Ordinary Shares to satisfy tax obligations arising from the vesting of restricted stock units, a common administrative transaction for equity compensation.

Was the Trinseo (TSE) insider transaction an open-market sale of shares?

No, the transaction was not an open-market sale. The filing shows a tax-withholding disposition, where 7,670 Ordinary Shares were retained by the company to cover taxes due upon restricted stock unit vesting, rather than a discretionary sale in the open market.

How many Trinseo (TSE) shares were involved in Paula M. Cooney’s tax-withholding event?

The tax-withholding transaction involved 7,670 Ordinary Shares. These shares were withheld by Trinseo to pay taxes owed when her restricted stock units vested, according to the Form 4 footnote describing the nature of the disposition.

What price per share was used in the Trinseo (TSE) tax-withholding disposition?

The shares in the tax-withholding disposition were valued at $0.23 per Ordinary Share. This price is disclosed in the Form 4 transaction details and is used solely to report the value of the shares applied toward Ms. Cooney’s tax liability.

How many Trinseo (TSE) shares does Paula M. Cooney hold after the reported transaction?

After the tax-withholding transaction, Paula M. Cooney directly owns 118,318 Ordinary Shares of Trinseo. This post-transaction ownership figure is reported in the Form 4 and reflects her holdings after the company withheld shares for taxes.

What does transaction code "F" mean in the Trinseo (TSE) Form 4 filing?

Transaction code “F” designates a tax-withholding disposition. In this case, it indicates Trinseo withheld 7,670 Ordinary Shares from Paula M. Cooney to satisfy tax liabilities resulting from restricted stock units vesting, rather than her selling shares on the market.