TSE Form 4: Sandra Beach Lin Disposes 10.3k Shares, Retains 44.8k

Rhea-AI Filing Summary

Insider transaction overview: Trinseo PLC (ticker: TSE) has filed a Form 4 reporting a routine tax-related share disposition by director Sandra Beach Lin.

• Transaction date: 21 June 2025
• Transaction code: F – shares withheld by the company to satisfy tax obligations upon vesting of previously granted restricted stock units
• Shares disposed: 10,310 ordinary shares
• Price: US $3.73 per share (as stated in the filing)
• Post-transaction ownership: 44,776 ordinary shares held directly

No derivative securities were acquired or disposed of, and no other insiders were included in the filing. Because the sale was coded “F,” it is classified as a non-discretionary transaction strictly for tax-withholding purposes, carrying limited signalling value regarding the insider’s outlook. The filing does, however, confirm Ms. Lin’s continuing equity stake of nearly forty-five thousand shares, aligning her interests with shareholders.

Insights

Corporate Governance Expert

TL;DR: Routine tax-withholding sale; immaterial strategic impact.

The Form 4 documents a code-F transaction in which Director Sandra Beach Lin surrendered 10,310 shares at US $3.73 to cover taxes on vested RSUs. Such dispositions are pre-programmed and do not typically reflect sentiment about Trinseo’s prospects. Post-transaction ownership of 44,776 shares indicates a continued, meaningful stake. No derivative activity was reported, and there is no evidence of open-market selling pressure. From a governance standpoint, disclosure is timely and compliant; from an investment standpoint, the event is neutral.

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^*

LIN SANDRA BEACH

(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		10,310(1)	D	$3.73	44,776	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 21 June 2025?

Director Sandra Beach Lin had 10,310 shares withheld (code F) to pay taxes on vested RSUs.

How many Trinseo shares does Sandra Beach Lin own after the Form 4 transaction?

She holds 44,776 ordinary shares directly after the tax-withholding event.

Was the share disposition a discretionary sale?

No. The transaction code F indicates an automatic, non-discretionary share surrender for tax withholding.

Were any derivative securities involved in this Form 4 filing?

No derivative securities were acquired or disposed of according to the filing’s Table II.

At what price were the 10,310 shares withheld?

The shares were valued at US $3.73 per share as disclosed in the filing.