[Form 4] Trinseo PLC Insider Trading Activity

Rhea-AI Filing Summary

Key facts from the Form 4 filing: On 06/25/2025 Trinseo PLC (ticker: TSE) reported that non-executive director Henri Steinmetz received 42,484 ordinary shares of the company under a restricted stock unit (RSU) award, recorded under transaction code “A” (grant without cash payment). The RSUs carry an acquisition price of $0 and will vest in full one year after the grant date, as noted in the explanatory footnote.

After the grant, Steinmetz’s total directly held stake rises to 95,937 shares. No derivative securities or additional transactions were disclosed, and the filing was made individually by Steinmetz (Form filed by one reporting person).

Investor take-aways:

• The transaction is a routine equity-based compensation grant for a board member, not an open-market purchase or sale. As such, it does not reflect active buying or selling sentiment.
• The incremental share issuance is de-minimis relative to Trinseo’s total shares outstanding and therefore has immaterial dilution impact on existing shareholders.
• Because the award vests after 12 months, it encourages continued board service and further aligns the director’s incentives with long-term shareholder value.

No financial results, guidance updates, or strategic developments accompanied the filing. Overall, the disclosure is administrative in nature and is unlikely to affect Trinseo’s near-term valuation or risk profile.

Insights

Equity Research Analyst

TL;DR: Routine RSU grant to director; negligible dilution; neutral for valuation.

The 42,484-share RSU grant to Director Steinmetz equates to well under 0.1% of Trinseo’s basic share count, implying virtually no EPS impact. Because the grant is cost-free and vests in a year, cash flow and near-term share supply remain unaffected. While the additional ownership can marginally strengthen alignment with investors, it does not signal insider conviction through open-market buying. From a valuation standpoint, the event is non-material; my impact rating is neutral.

Corporate Governance Specialist

TL;DR: Governance-friendly equity award; aligns incentives but not market-moving.

The filing shows Trinseo adhering to standard board compensation practice—annual RSUs that vest after 12 months. Such awards encourage director retention and emphasize long-term performance, both positives from a governance lens. However, investors should not read this as an active bullish signal because no personal capital was committed. The scale is too small to alter ownership dynamics at the board level. Overall effect on shareholder rights and control is negligible, hence a neutral impact score.

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)
06/25/2025

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	06/25/2025		A		42,484(1)	A	$0	95,937	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. Represents ordinary shares issuable pursuant to a restricted stock unit award that will vest in full on the first anniversary of the grant date.

	/s/ Angelo Chaclas, Attorney-in-Fact	06/27/2025
	** 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

How many Trinseo (TSE) shares did Director Henri Steinmetz acquire?

He was awarded 42,484 ordinary shares through an RSU grant.

Was any cash paid for the 42,484 Trinseo shares?

No. The RSU award was recorded at $0 acquisition price.

What is Henri Steinmetz’s total Trinseo ownership after the transaction?

His direct beneficial ownership increased to 95,937 shares.

When will the newly granted RSUs to Steinmetz vest?

The RSUs vest in full one year after the 06/25/2025 grant date.

Does this Form 4 indicate insider buying or selling in the open market?

No. It reflects a routine equity compensation grant, not an open-market trade.