Trinseo (TSE) director Victoria Brifo forfeits 42,484 unvested RSUs, holds 40,741 shares

Rhea-AI Filing Summary

Trinseo PLC director Victoria Brifo reported a compensation-related change in equity awards. The filing shows a voluntary forfeiture of 42,484 restricted stock units that had been granted on June 25, 2025 and had not yet vested or been settled. These units were given up without any share price involved. After this adjustment, Brifo directly holds 40,741 Ordinary Shares, indicating she retains a meaningful equity stake in the company despite the forfeiture.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Brifo Victoria

Role null

Type	Security	Shares	Price	Value
Other	Ordinary Shares	42,484	$0.00	--

Holdings After Transaction: Ordinary Shares — 40,741 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

RSUs forfeited: 42,484 units Shares after transaction: 40,741 shares Transaction price: 0.0000 per share +1 more

4 metrics

RSUs forfeited 42,484 units Voluntary forfeiture of unvested restricted stock units

Shares after transaction 40,741 shares Ordinary Shares directly held following Form 4 event

Transaction price 0.0000 per share Indicates no cash consideration for forfeited units

Transaction shares 42,484 shares Non-derivative entry tied to RSU forfeiture

Key Terms

restricted stock units ("RSUs"), voluntary forfeiture, vested or settled, Ordinary Shares

4 terms

restricted stock units ("RSUs") financial

"Reflects a voluntary forfeiture by the Reporting Person of restricted stock units ("RSUs")"

Restricted stock units (RSUs) are a company promise to give an employee shares of stock (or cash equivalent) in the future, but only after certain conditions—usually staying with the company for a set time or hitting performance goals—are met. Investors watch RSUs because when they vest they increase the number of shares outstanding and can lead insiders to sell shares, affecting share price, company dilution and the true cost of employee pay.

voluntary forfeiture financial

"Reflects a voluntary forfeiture by the Reporting Person of restricted stock units"

vested or settled financial

"At the time of forfeiture, the RSU award was not vested or settled, in full or in part."

Ordinary Shares financial

"security_title: "Ordinary Shares""

Ordinary shares are a type of ownership stake in a company, giving shareholders a right to participate in the company’s profits and decision-making through voting. They are similar to owning a piece of a business, and their value can rise or fall based on the company's performance. Investors buy ordinary shares to potentially earn dividends and benefit from the company's growth over time.

Form 4 Insider Transactions: What Each Field Means →

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
Estimated average burden
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 PENNSYLVANIA 19087

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/12/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	05/12/2026		J(1)		42,484	D	(1)	40,741	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. Reflects a voluntary forfeiture by the Reporting Person of restricted stock units ("RSUs") that were previously granted on June 25, 2025. At the time of forfeiture, the RSU award was not vested or settled, in full or in part.

	/s/ Angelo Chaclas, Attorney-in-Fact	05/14/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Trinseo (TSE) director Victoria Brifo report?

Victoria Brifo reported a voluntary forfeiture of 42,484 restricted stock units. These RSUs had been previously granted but were not yet vested or settled, and were surrendered without any share price involved, reflecting a compensation-related adjustment rather than a market trade.

How many Trinseo (TSE) shares does Victoria Brifo hold after the Form 4 transaction?

After the reported transaction, Victoria Brifo directly holds 40,741 Ordinary Shares of Trinseo PLC. This amount reflects her remaining equity position following the voluntary forfeiture of unvested restricted stock units described in the Form 4 filing.

Was the Trinseo (TSE) insider transaction a market buy or sell of shares?

The transaction was not a market buy or sell. It was a voluntary forfeiture of 42,484 unvested restricted stock units, recorded at a price of 0.0000 per share, indicating no open-market trading or cash consideration was involved in this adjustment.

What does the forfeiture of Trinseo (TSE) restricted stock units mean for shareholders?

The forfeiture represents a change in one director’s unvested equity awards, not a cash sale or purchase. It adjusts Victoria Brifo’s potential future share-based compensation while leaving her with 40,741 Ordinary Shares directly held in Trinseo PLC after the transaction.

How is the Trinseo (TSE) Form 4 transaction classified by the SEC code?

The transaction is coded as “J,” meaning “Other acquisition or disposition.” In this case, it reflects a restructuring-type event, where 42,484 unvested restricted stock units were voluntarily forfeited rather than exercised, sold, or transferred in an open-market trade.