[Form 4] Trinseo PLC Insider Trading Activity

Rhea-AI Filing Summary

Form 4 Overview: Trinseo PLC (ticker: TSE) filed a Form 4 disclosing that board director Victoria Brifo was granted 42,484 ordinary shares in the form of restricted stock units (RSUs) on 25 June 2025. The RSUs will vest in full on the first anniversary of the grant date, subject to continued service.

Following this award, Brifo’s total beneficial ownership rises to 83,225 ordinary shares. The transaction is coded “A” (acquired) at a price of $0, indicating an equity compensation grant rather than an open-market purchase. There were no derivative securities reported and no dispositions.

Key Takeaways for Investors:

• The award increases insider equity alignment but does not represent cash outlay by the director.
• The single-line nature of the filing suggests no other insider trades on the date.
• No indication of 10b5-1 trading plan was checked, implying the grant was standard board compensation.

Positive

• Director’s beneficial ownership increases to 83,225 shares, marginally strengthening insider alignment with shareholders.

Negative

• Shares were awarded at $0 cost; the transaction is compensation-related rather than a voluntary market purchase, thus offers limited valuation signal.

Insights

Financial Analyst

TL;DR: Routine RSU grant; modestly positive alignment, limited market signal.

The filing shows a standard annual equity grant to a non-executive director. Because the shares vest in one year and carry a $0 cost basis, the award improves ownership alignment without requiring a capital commitment. However, the absence of an open-market purchase limits its signaling power regarding management’s short-term view of valuation. Material impact on share float or earnings per share is negligible given Trinseo’s ~35 million share count.

Corporate Governance Expert

TL;DR: Governance-aligned compensation; neutral financial impact.

Granting directors annual RSUs is consistent with best-practice governance, tying board compensation to long-term performance. Vesting after one year encourages at least medium-term oversight. The director now owns 83,225 shares, providing a reasonable stake but not large enough to influence control. Investors should view this as routine and not indicative of strategic change.

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^*

Brifo Victoria

(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	83,225	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 Victoria Brifo acquire according to the Form 4?

The filing reports an acquisition of 42,484 ordinary shares via restricted stock units.

What is Victoria Brifo’s total beneficial ownership in TSE after the transaction?

After the RSU grant, Brifo beneficially owns 83,225 Trinseo shares.

Was the acquisition an open-market purchase?

No. The transaction code “A” and $0 price indicate it was an equity compensation grant, not a market purchase.

When will the restricted stock units granted to Brifo vest?

The RSUs will vest in full on 25 June 2026, one year after the grant date.

Does the Form 4 mention any shares sold or derivative securities involved?

No. The filing lists only the RSU grant; no sales or derivative positions were reported.