[Form 4] Trinseo PLC Insider Trading Activity

Rhea-AI Filing Summary

SEC Form 4 snapshot – Trinseo PLC (TSE): Director Henri Steinmetz reported a code “F” transaction on 06/21/2025, indicating shares were withheld by the company to satisfy tax obligations arising from the vesting of restricted stock units.

Key figures

• Shares disposed: 20,001 ordinary shares
• Implied price: $3.73 per share
• Remaining direct holdings: 53,453 shares
• No derivative securities were bought or sold

Because code “F” transactions are administrative rather than discretionary sales, the filing is typically viewed as neutral to sentiment, though it does reduce the director’s stake by roughly 27% and marginally increases the public float.

Positive

• None.

Negative

• Director Henri Steinmetz’s direct stake fell by 20,001 shares (≈27%), incrementally lowering insider ownership, even though the disposal was strictly for tax withholding.

Insights

Securities Analyst

TL;DR: Administrative tax-withholding sale; limited market signal.

The 20,001-share disposal is coded “F,” confirming it was company-withheld to cover taxes on RSU vesting, not an open-market sale. While the director’s position drops to 53,453 shares, the transaction does not reflect a change in conviction. With no derivative activity or multiple insiders involved, the impact on valuation or liquidity is negligible.

Corporate Governance Expert

TL;DR: Routine insider tax event; governance risk unchanged.

Rule 10b5-1 safe-harbor is referenced, and the filing is timely, supporting compliance quality. The 27% reduction in direct ownership warrants monitoring, yet because the shares never entered the open market, governance implications remain neutral. Investors should focus on broader strategic updates, not this administrative share movement.

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
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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^*

STEINMETZ HENRI

(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
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
06/21/2025

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	06/21/2025		F		20,001(1)	D	$3.73	53,453	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	06/24/2025
	** 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 on Form 4?

20,001 ordinary shares were disposed of on 06/21/2025 under code “F,” meaning they were withheld to pay taxes on vested RSUs.

How many Trinseo shares does Henri Steinmetz own after the transaction?

The director now holds 53,453 ordinary shares directly.

What does transaction code "F" indicate on SEC Form 4?

Code “F” signifies shares withheld by the issuer to satisfy an insider’s tax liability from equity award vesting.

Were any derivative securities involved in this filing?

No; the filing shows no derivative security transactions for the period.

At what price were the withheld Trinseo shares valued?

The shares were valued at $3.73 each for tax-withholding purposes.