Trinseo (NYSE: TSE) CTO covers tax obligations with share dispositions

Rhea-AI Filing Summary

Trinseo PLC senior executive reports tax-related share dispositions. SVP and Chief Technology Officer Han Hendriks reported two Form 4 transactions where Ordinary Shares were withheld by the company to cover taxes owed on vested restricted stock units. On February 21, 2026, 6,331 Ordinary Shares were withheld at $0.3276 per share. On February 22, 2026, a further 2,291 Ordinary Shares were withheld at $0.3276 per share. These code F transactions reflect tax-withholding dispositions rather than open-market purchases or sales.

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

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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^*

Hendriks Han

(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, CHIEF TECHNOLOGY OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
02/21/2026

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	02/21/2026		F		6,331(1)	D	$0.3276	83,360	D
Ordinary Shares	02/22/2026		F		2,291(1)	D	$0.3276	81,069	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 transactions did Trinseo (TSE) report for Han Hendriks?

Trinseo reported two Form 4 transactions for SVP and CTO Han Hendriks. The company withheld 6,331 and 2,291 Ordinary Shares to satisfy tax obligations arising from restricted stock unit vesting.

Were Han Hendriks’ Trinseo (TSE) share transactions open-market sales?

No, the transactions were not open-market sales. The shares were withheld by Trinseo to pay taxes due when restricted stock units vested, coded as tax-withholding dispositions under transaction code F.

How many Trinseo (TSE) shares were withheld for Han Hendriks’ taxes?

A total of 6,331 Ordinary Shares were withheld on February 21, 2026, and 2,291 Ordinary Shares on February 22, 2026, to cover tax liabilities from vested restricted stock units.

What price per share was used in Han Hendriks’ Trinseo (TSE) tax dispositions?

Both tax-withholding dispositions used a price of $0.3276 per Ordinary Share. This price was applied to the 6,331-share and 2,291-share withholdings reported in the Form 4 filing.

What does transaction code F mean in Trinseo (TSE) insider filings?

Transaction code F indicates shares were disposed of to pay an exercise price or tax liability. In this case, Trinseo withheld Ordinary Shares from Han Hendriks to satisfy taxes on restricted stock unit vesting.

Does Han Hendriks still hold Trinseo (TSE) shares after these transactions?

Yes, the Form 4 shows that Han Hendriks continued to hold Ordinary Shares directly after each tax-withholding transaction, with updated post-transaction ownership amounts reported for each date.