Insider Transactions Reported by 33 Insiders of Trinseo PLC

Symbol: TSEOF on OTC
Location: Wayne, PA

Quick Takeaways

TSEOF - Trinseo PLC has 33 insiders with reported activity on this page.
Net insider value flow over the last year: +$240,028.
Recent transaction rows are available for direct filing-level review.

What Changed

Buy value: $240,028; sell value: $0.
Net share flow: +100,000.

Why This Matters

This page gives a plain-language issuer insider context before you inspect transaction-level evidence.
Use the filing links below to verify timestamps, codes, and ownership impacts directly from SEC forms.

Source Evidence

Filed on Form 4

Issuer insider activity is sourced from SEC Forms 3, 4, and 5.

See Original Filing

Insider trading overview

Last 12 months

Net insider flow leans to buying over the last 12 months. Net value: +$240,028.

Buys

$240,028

Shares: 100,000

Insiders: 1

Sells

Shares: 0

Insiders: 0

Net

+$240,028

Shares: +100,000

Insiders: 1

Window (months)	Buy shares	Buy $	Sell $	Net $
0-3	0	$0	$0	$0
3-6	0	$0	$0	$0
6-9	48,609	$118,120	$0	+$118,120
9-12	51,391	$121,908	$0	+$121,908

Trinseo PLC executives and other stock owners filed with the SEC include:

Name	Relationship	Holdings Value	Past Year Net Change	Change %	Valuation	Report Date
M&G INVESTMENT MANAGEMENT LTD	10%+ Owner	$54,976,567			Mixed	19 Jul 2022
Jeffrey J. Cote	Director	$721,733			Mixed	25 Jun 2025
Matthew Farrell	Director	$608,046	+$240,028	+65%	Filing P/S	12 Aug 2025
Henri Steinmetz	Director	$267,664			Mixed	25 Jun 2025
Joseph Alvarado	Director	$264,132			Mixed	25 Jun 2025
Klynne Johnson	Director	$253,647			Mixed	25 Jun 2025
Jeanmarie F. Desmond	Director	$248,410			Mixed	25 Jun 2025
Sandra Beach Lin	Director	$243,455			Mixed	25 Jun 2025
Victoria Brifo	Director	$232,197			Mixed	25 Jun 2025
Frank A. Bozich	CEO AND PRESIDENT, Director	$152,878			Mixed	27 Feb 2026
Misheff Donald T.	Director	$141,705			Mixed	14 Jun 2023
Mark E. Tomkins	Director	$136,588			Mixed	21 Jun 2025
Pierre-Marie de Leener	Director	$134,929			Mixed	21 Jun 2025
Andre Lanning	Svp & Cco	$130,825			Mixed	25 Feb 2023
Nicolas Joly	SVP, Styrenics	$107,631			Mixed	25 Feb 2023
Bernard M. Skeete	VP, CAO & Global Controller	$92,447			Mixed	25 Feb 2023
Timothy J. Thomas	Svp, Mfctg & Oper Excellence	$84,783			Mixed	17 Feb 2024
Alice Heezen	SVP - Human Resources	$72,684			Mixed	12 Nov 2021
Philip R. Martens	Director	$67,875			Mixed	14 Jun 2023
Jean-Luc Beal	SVP, Engineered Materials	$66,721			Mixed	22 Feb 2023
Angelo N. Chaclas	Svp, Clo, Cco & Corp. Sec.	$63,203			Mixed	27 Feb 2026
David Phillip Stasse	Evp And Cfo	$58,601			Mixed	27 Feb 2026
Johanna Frisch	Vp And Treasurer	$37,360			Mixed	30 Sep 2025
Francesca Reverberi	SVP, EM and Polymer Solutions	$37,087			Mixed	27 Feb 2026
James Mingyu Ni	Svp, Latex Binders	$33,001			Mixed	17 Feb 2024
Paula M. Cooney	Svp, Chro	$27,213			Mixed	27 Feb 2026
Rainer Schewe	Svp, Supply Chain & Mfg Svcs	$23,785			Mixed	27 Feb 2026
Bregje van Kessel	SVP, Corporate Finance & IR	$22,608			Mixed	27 Feb 2026
Han Hendriks	Svp, Chief Technology Officer	$16,873			Mixed	27 Feb 2026
Arthas Bing Yang	SVP, Latex Binders	$11,375			Mixed	27 Feb 2026
Roger Greene	Vp, Global Controller & Pao	$10,373			Mixed	27 Feb 2026
Carol Flaton	Director				Mixed	16 Jan 2026
Jill Kathleen Frizzley	Director				Mixed	16 Jan 2026

Top shareholders of Trinseo PLC (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Ownership % is shown only when it is directly reported or safely comparable across share classes.

Methodology: rows are grouped by holder and ranked by the holder's primary source value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

Holder	Source	Role / Reporting	Ownership %	Shares	Holdings Value	12M Net Δ	As of	Details
M&G INVESTMENT MANAGEMENT LTD	3/4/5	10%+ Owner	— class O/S missing	7,625,044	$54,976,567	—	19 Jul 2022	3/4/5
BlackRock, Inc.	13D/G 13F	Company	6.3%	2,255,125	$8,456,719	$0	30 Jun 2025	13D/G 13F
M&G Plc	13F	Company	21%	7,625,044	$3,789,647	—	31 Dec 2025	13F
CHARLES SCHWAB INVESTMENT MANAGEMENT INC	13D/G 13F	Company	5.8%	2,091,125	$1,693,811	$0	31 Dec 2025	13D/G 13F
Owl Creek Asset Management, L.P.	13F	Company	4.5%	1,669,952	$829,966	—	31 Dec 2025	13F
Jeffrey J. Cote	3/4/5	Director	0.7%	258,686	$721,733	—	25 Jun 2025	3/4/5
Matthew Farrell	3/4/5	Director	0.68%	250,225	$608,046	+$240,028	12 Aug 2025	3/4/5
ICON ADVISERS INC/CO	13F	Company	2.7%	1,000,000	$497,000	—	31 Dec 2025	13F
CastleKnight Master Fund LP	13D/G	—	1.4%	516,826	$418,629	-$1,822,014	31 Dec 2025	13D/G
GEODE CAPITAL MANAGEMENT, LLC	13F	Company	2.3%	841,720	$418,419	—	31 Dec 2025	13F
VANGUARD GROUP INC	13F	Company	2.1%	762,828	$379,126	—	31 Dec 2025	13F
GOLDMAN SACHS GROUP INC	13F	Company	1.6%	580,623	$288,569	—	31 Dec 2025	13F
Henri Steinmetz	3/4/5	Director	0.26%	95,937	$267,664	—	25 Jun 2025	3/4/5
MORGAN STANLEY	13F	Company	1.5%	536,422	$266,601	—	31 Dec 2025	13F
Joseph Alvarado	3/4/5	Director	0.26%	94,671	$264,132	—	25 Jun 2025	3/4/5
CastleKnight Management LP	13F	Company	1.4%	516,826	$256,863	—	31 Dec 2025	13F
GSA CAPITAL PARTNERS LLP	13F	Company	1.4%	511,342	$254,000	—	31 Dec 2025	13F
Klynne Johnson	3/4/5	Director	0.25%	90,913	$253,647	—	25 Jun 2025	3/4/5
Jeanmarie F. Desmond	3/4/5	Director	0.24%	89,036	$248,410	—	25 Jun 2025	3/4/5
Sandra Beach Lin	3/4/5	Director	0.24%	87,260	$243,455	—	25 Jun 2025	3/4/5
STATE STREET CORP	13F	Company	1.3%	478,033	$237,582	—	31 Dec 2025	13F
Victoria Brifo	3/4/5	Director	0.23%	83,225	$232,197	—	25 Jun 2025	3/4/5
Frank A. Bozich	3/4/5	CEO AND PRESIDENT, Director	1.8%	664,689	$152,878	—	27 Feb 2026	3/4/5
Misheff Donald T.	3/4/5	Director	— class O/S missing	19,654	$141,705	—	14 Jun 2023	3/4/5
LAKEWOOD CAPITAL MANAGEMENT, LP	13F	Company	0.76%	281,279	$139,796	—	31 Dec 2025	13F
RENAISSANCE TECHNOLOGIES LLC	13F	Company	0.75%	276,100	$137,222	—	31 Dec 2025	13F
Mark E. Tomkins	3/4/5	Director	0.1%	36,619	$136,588	—	21 Jun 2025	3/4/5
Pierre-Marie de Leener	3/4/5	Director	0.1%	36,174	$134,929	—	21 Jun 2025	3/4/5
Andre Lanning	3/4/5	SVP & CCO	— mixed-class rows	38,440 mixed-class rows	$130,825	—	25 Feb 2023	3/4/5
NORTHERN TRUST CORP	13F	Company	0.67%	245,801	$122,163	—	31 Dec 2025	13F
Nicolas Joly	3/4/5	SVP, Styrenics	— mixed-class rows	24,018 mixed-class rows	$107,631	—	25 Feb 2023	3/4/5
Bernard M. Skeete	3/4/5	VP, CAO & Global Controller	— mixed-class rows	17,672 mixed-class rows	$92,447	—	25 Feb 2023	3/4/5
UBS Group AG	13F	Company	0.5%	184,497	$91,695	—	31 Dec 2025	13F
Timothy J. Thomas	3/4/5	SVP, MFCTG & OPER EXCELLENCE	— class O/S missing	17,737	$84,783	—	17 Feb 2024	3/4/5
Alta Fundamental Advisers LLC	13F	Company	0.41%	152,974	$76,028	—	31 Dec 2025	13F
Alice Heezen	3/4/5	SVP - Human Resources	— mixed-class rows	12,763 mixed-class rows	$72,684	—	12 Nov 2021	3/4/5
Philip R. Martens	3/4/5	Director	— class O/S missing	9,414	$67,875	—	14 Jun 2023	3/4/5
Jean-Luc Beal	3/4/5	SVP, Engineered Materials	— mixed-class rows	18,133 mixed-class rows	$66,721	—	22 Feb 2023	3/4/5
Angelo N. Chaclas	3/4/5	SVP, CLO, CCO & CORP. SEC.	0.74%	274,798	$63,203	—	27 Feb 2026	3/4/5
DEUTSCHE BANK AG\	13F	Company	0.34%	125,610	$62,805	—	31 Dec 2025	13F
David Phillip Stasse	3/4/5	EVP AND CFO	0.69%	254,788	$58,601	—	27 Feb 2026	3/4/5
DIMENSIONAL FUND ADVISORS LP	13F	Company	0.27%	98,606	$49,071	—	31 Dec 2025	13F
Bank of New York Mellon Corp	13F	Company	0.22%	80,741	$40,129	—	31 Dec 2025	13F
Johanna Frisch	3/4/5	VP AND TREASURER	0.04%	15,898	$37,360	—	30 Sep 2025	3/4/5
Francesca Reverberi	3/4/5	SVP, EM and Polymer Solutions	0.44%	161,250	$37,087	—	27 Feb 2026	3/4/5
Invesco Ltd.	13F	Company	0.19%	70,320	$34,949	—	31 Dec 2025	13F
FMR LLC	13F	Company	0.18%	67,624	$33,609	—	31 Dec 2025	13F
James Mingyu Ni	3/4/5	SVP, LATEX BINDERS	— mixed-class rows	15,818 mixed-class rows	$33,001	—	17 Feb 2024	3/4/5
Paula M. Cooney	3/4/5	SVP, CHRO	0.32%	118,318	$27,213	—	27 Feb 2026	3/4/5
BARCLAYS PLC	13F	Company	0.14%	53,255	$26,467	—	31 Dec 2025	13F

Recent Insider Transactions by Companies or Individuals for Trinseo PLC

Showing up to 300 most recent insider transactions from the last 12 months.

Insider	Symbol	Class	Transaction	%	Value $	* Price $	Shares	Shares Owned	Date	Ownership
Arthas Bing Yang	TSE	Ordinary Shares	Tax liability	-4.9%			-2,548	49,457	27 Feb 2026	Direct
Bregje van Kessel	TSE	Ordinary Shares	Tax liability	-5.81%			-6,064	98,296	27 Feb 2026	Direct
Rainer Schewe	TSE	Ordinary Shares	Tax liability	-3.75%			-4,028	103,415	27 Feb 2026	Direct
Francesca Reverberi	TSE	Ordinary Shares	Tax liability	-0.85%			-1,385	161,250	27 Feb 2026	Direct
Han Hendriks	TSE	Ordinary Shares	Tax liability	-9.51%			-7,707	73,362	27 Feb 2026	Direct
Roger Greene	TSE	Ordinary Shares	Tax liability	-5.29%			-2,517	45,101	27 Feb 2026	Direct
Paula M. Cooney	TSE	Ordinary Shares	Tax liability	-6.09%			-7,670	118,318	27 Feb 2026	Direct
Angelo N. Chaclas	TSE	Ordinary Shares	Tax liability	-2.69%			-7,607	274,798	27 Feb 2026	Direct
David Phillip Stasse	TSE	Ordinary Shares	Tax liability	-3.91%			-10,366	254,788	27 Feb 2026	Direct
Frank A. Bozich	TSE	Ordinary Shares	Tax liability	-3.44%			-23,680	664,689	27 Feb 2026	Direct
Francesca Reverberi	TSE	Ordinary Shares	Tax liability	-0.2%			-333	162,635	22 Feb 2026	Direct
Han Hendriks	TSE	Ordinary Shares	Tax liability	-2.75%			-2,291	81,069	22 Feb 2026	Direct
Arthas Bing Yang	TSE	Ordinary Shares	Tax liability	-1.04%			-547	52,005	22 Feb 2026	Direct
Bregje van Kessel	TSE	Ordinary Shares	Tax liability	-1.26%			-1,335	104,360	22 Feb 2026	Direct
Rainer Schewe	TSE	Ordinary Shares	Tax liability	-1.11%			-1,206	107,443	22 Feb 2026	Direct
Paula M. Cooney	TSE	Ordinary Shares	Tax liability	-2.09%			-2,684	125,988	22 Feb 2026	Direct
David Phillip Stasse	TSE	Ordinary Shares	Tax liability	-3.52%			-9,671	265,154	22 Feb 2026	Direct
Frank A. Bozich	TSE	Ordinary Shares	Tax liability	-4.52%			-32,602	688,369	22 Feb 2026	Direct
Angelo N. Chaclas	TSE	Ordinary Shares	Tax liability	-2.45%			-7,098	282,405	22 Feb 2026	Direct
Francesca Reverberi	TSE	Ordinary Shares	Tax liability	-0.71%			-1,163	162,968	21 Feb 2026	Direct
Han Hendriks	TSE	Ordinary Shares	Tax liability	-7.06%			-6,331	83,360	21 Feb 2026	Direct
Arthas Bing Yang	TSE	Ordinary Shares	Tax liability	-3.49%			-1,898	52,552	21 Feb 2026	Direct
Bregje van Kessel	TSE	Ordinary Shares	Tax liability	-5.34%			-5,963	105,695	21 Feb 2026	Direct
Rainer Schewe	TSE	Ordinary Shares	Tax liability	-3.47%			-3,907	108,649	21 Feb 2026	Direct
Paula M. Cooney	TSE	Ordinary Shares	Tax liability	-5.47%			-7,440	128,672	21 Feb 2026	Direct
Roger Greene	TSE	Ordinary Shares	Tax liability	-4.49%			-2,238	47,618	21 Feb 2026	Direct
David Phillip Stasse	TSE	Ordinary Shares	Tax liability	-1.8%			-5,028	274,825	21 Feb 2026	Direct
Angelo N. Chaclas	TSE	Ordinary Shares	Tax liability	-1.26%			-3,690	289,503	21 Feb 2026	Direct
Han Hendriks	TSE	Ordinary Shares	Tax liability	-2.25%			-2,067	89,691	03 Oct 2025	Direct
Johanna Frisch	TSE	Ordinary Shares	Tax liability	-12.1%			-2,194	15,898	30 Sep 2025	Direct
Roger Greene	TSE	Ordinary Shares	Tax liability	-3.14%			-1,617	49,856	25 Sep 2025	Direct
Matthew Farrell	TSE	Ordinary Shares	Purchase	24.1%	$118,120	$2.43	48,609	250,225	14 Aug 2025	Direct
Matthew Farrell	TSE	Ordinary Shares	Purchase	15.1%	$64,658	$2.45	26,391	201,616	13 Aug 2025	Direct
Matthew Farrell	TSE	Ordinary Shares	Purchase	16.6%	$57,250	$2.29	25,000	175,225	12 Aug 2025	Direct
Joseph Alvarado	TSE	Ordinary Shares	Award	81.4%			42,484	94,671	25 Jun 2025	Direct
Sandra Beach Lin	TSE	Ordinary Shares	Award	94.9%			42,484	87,260	25 Jun 2025	Direct
Victoria Brifo	TSE	Ordinary Shares	Award	104.3%			42,484	83,225	25 Jun 2025	Direct
Jeffrey J. Cote	TSE	Ordinary Shares	Award	93%			42,484	88,183	25 Jun 2025	Direct
Jeanmarie F. Desmond	TSE	Ordinary Shares	Award	91.3%			42,484	89,036	25 Jun 2025	Direct
Matthew Farrell	TSE	Ordinary Shares	Award	39.4%			42,484	150,225	25 Jun 2025	Direct
Klynne Johnson	TSE	Ordinary Shares	Award	87.7%			42,484	90,913	25 Jun 2025	Direct
Henri Steinmetz	TSE	Ordinary Shares	Award	79.5%			42,484	95,937	25 Jun 2025	Direct
Jeffrey J. Cote	TSE	Ordinary Shares	Tax liability	-18.4%			-10,310	45,699	21 Jun 2025	Direct
Mark E. Tomkins	TSE	Ordinary Shares	Tax liability	-21.6%			-10,105	36,619	21 Jun 2025	Direct
Henri Steinmetz	TSE	Ordinary Shares	Tax liability	-27.2%			-20,001	53,453	21 Jun 2025	Direct
Sandra Beach Lin	TSE	Ordinary Shares	Tax liability	-18.7%			-10,310	44,776	21 Jun 2025	Direct
Matthew Farrell	TSE	Ordinary Shares	Tax liability	-8.16%			-9,576	107,741	21 Jun 2025	Direct
Pierre-Marie de Leener	TSE	Ordinary Shares	Tax liability	-35.6%			-20,001	36,174	21 Jun 2025	Direct
Victoria Brifo	TSE	Ordinary Shares	Tax liability	-19%			-9,576	40,741	21 Jun 2025	Direct
Klynne Johnson	TSE	Ordinary Shares	Tax liability	-17.8%			-10,474	48,429	21 Jun 2025	Direct

* An asterisk sign (*) next to the price indicates that the price is likely invalid.