Trinseo PLC

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Date	Name	Title	Shares	Value	Transaction
May 12, 2026	ALVARADO JOSEPH	Director	42,484Ordinary Shares	—	Other
May 12, 2026	FARRELL MATTHEW	Director	42,484Ordinary Shares	—	Other
May 12, 2026	COTE JEFFREY J	Director	42,484Ordinary Shares	—	Other
May 12, 2026	STEINMETZ HENRI	Director	42,484Ordinary Shares	—	Other
May 12, 2026	LIN SANDRA BEACH	Director	42,484Ordinary Shares	—	Other
May 12, 2026	Johnson KLynne	Director	42,484Ordinary Shares	—	Other
May 12, 2026	Desmond Jeanmarie F.	Director	42,484Ordinary Shares	—	Other
May 12, 2026	Brifo Victoria	Director	42,484Ordinary Shares	—	Other
Feb 27, 2026	Stasse David Phillip	EVP AND CFO	10,366Ordinary Shares	—	Tax withholding
Feb 27, 2026	Chaclas Angelo N.	SVP, CLO, CCO & CORP. SEC.	7,607Ordinary Shares	—	Tax withholding