Insider Transactions Reported by 33 Insiders of Trinseo PLC

Symbol: TSEOF on OTC
Location: Wayne, PA

Key facts

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.

Change

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

Research use

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.

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	0	$0	$0	$0
9-12	100,000	$240,028	$0	+$240,028

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	12 May 2026
Matthew Farrell	Director	$608,046	+$240,028	+65%	Mixed	12 May 2026
Henri Steinmetz	Director	$267,664			Mixed	12 May 2026
Joseph Alvarado	Director	$264,132			Mixed	12 May 2026
Klynne Johnson	Director	$253,647			Mixed	12 May 2026
Jeanmarie F. Desmond	Director	$248,410			Mixed	12 May 2026
Sandra Beach Lin	Director	$243,455			Mixed	12 May 2026
Victoria Brifo	Director	$232,197			Mixed	12 May 2026
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 first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings 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
Nut Tree Capital Management, LP	13D/G	—	8.3%	3,027,280	—	$0	31 Mar 2026	13D/G
BlackRock, Inc.	13D/G	—	6.3%	2,255,125	$8,456,719	$0	30 Jun 2025	13D/G
CHARLES SCHWAB INVESTMENT MANAGEMENT INC	13D/G	—	5.8%	2,091,125	$1,693,811	$0	31 Dec 2025	13D/G
CastleKnight Master Fund LP	13D/G	—	1.4%	516,826	$418,629	-$1,822,014	31 Dec 2025	13D/G
Frank A. Bozich	3/4/5	CEO AND PRESIDENT, Director	1.8%	664,689	$152,878	—	27 Feb 2026	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
David Phillip Stasse	3/4/5	EVP AND CFO	0.69%	254,788	$58,601	—	27 Feb 2026	3/4/5
Jeffrey J. Cote	3/4/5	Director	0.59%	216,202	$721,733	—	12 May 2026	3/4/5
Matthew Farrell	3/4/5	Director	0.57%	207,741	$608,046	+$240,028	12 May 2026	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
Paula M. Cooney	3/4/5	SVP, CHRO	0.32%	118,318	$27,213	—	27 Feb 2026	3/4/5
Rainer Schewe	3/4/5	SVP, SUPPLY CHAIN & MFG SVCS	0.28%	103,415	$23,785	—	27 Feb 2026	3/4/5
Bregje van Kessel	3/4/5	SVP, Corporate Finance & IR	0.27%	98,296	$22,608	—	27 Feb 2026	3/4/5
Han Hendriks	3/4/5	SVP, CHIEF TECHNOLOGY OFFICER	0.2%	73,362	$16,873	—	27 Feb 2026	3/4/5
Henri Steinmetz	3/4/5	Director	0.15%	53,453	$267,664	—	12 May 2026	3/4/5
Joseph Alvarado	3/4/5	Director	0.14%	52,187	$264,132	—	12 May 2026	3/4/5
Arthas Bing Yang	3/4/5	SVP, Latex Binders	0.13%	49,457	$11,375	—	27 Feb 2026	3/4/5
Klynne Johnson	3/4/5	Director	0.13%	48,429	$253,647	—	12 May 2026	3/4/5
Jeanmarie F. Desmond	3/4/5	Director	0.13%	46,552	$248,410	—	12 May 2026	3/4/5
Sandra Beach Lin	3/4/5	Director	0.12%	44,776	$243,455	—	12 May 2026	3/4/5
Roger Greene	3/4/5	VP, GLOBAL CONTROLLER & PAO	0.12%	45,101	$10,373	—	27 Feb 2026	3/4/5
Victoria Brifo	3/4/5	Director	0.11%	40,741	$232,197	—	12 May 2026	3/4/5
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
Johanna Frisch	3/4/5	VP AND TREASURER	0.04%	15,898	$37,360	—	30 Sep 2025	3/4/5
Kohmann Bosshard Financial Services, LLC	13F	Company	0.12%	44,605	$4,684	—	31 Mar 2026	13F
Nuveen, LLC	13F	Company	0.12%	44,280	$4,649	—	31 Mar 2026	13F
EverSource Wealth Advisors, LLC	13F	Company	0.01%	5,430	$570	—	31 Mar 2026	13F
BARCLAYS PLC	13F	Company	0.01%	4,802	$505	—	31 Mar 2026	13F
GAMMA Investing LLC	13F	Company	0.01%	2,148	$226	—	31 Mar 2026	13F
RHUMBLINE ADVISERS	13F	Company	0%	1,654	$173	—	31 Mar 2026	13F
McIlrath & Eck, LLC	13F	Company	0%	1,444	$152	—	31 Mar 2026	13F
SWAN Capital LLC	13F	Company	0%	250	$26	—	31 Mar 2026	13F
Rockefeller Capital Management L.P.	13F	Company	0%	160	$17	—	31 Mar 2026	13F
Essential Partners LLC	13F	Company	0%	66	$7	—	31 Mar 2026	13F
Sunbelt Securities, Inc.	13F	Company	0%	64	$7	—	31 Mar 2026	13F
IFP Advisors, Inc	13F	Company	0%	55	$6	—	31 Mar 2026	13F
Farther Finance Advisors, LLC	13F	Company	0%	15	$2	—	31 Mar 2026	13F
ROTHSCHILD INVESTMENT LLC	13F	Company	0%	7	$1	—	31 Mar 2026	13F
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
Misheff Donald T.	3/4/5	Director	— class O/S missing	19,654	$141,705	—	14 Jun 2023	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
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
Timothy J. Thomas	3/4/5	SVP, MFCTG & OPER EXCELLENCE	— class O/S missing	17,737	$84,783	—	17 Feb 2024	3/4/5
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
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

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
Sandra Beach Lin	TSEOF	Ordinary Shares	Other	-48.7%			-42,484	44,776	12 May 2026	Direct
Jeanmarie F. Desmond	TSEOF	Ordinary Shares	Other	-47.7%			-42,484	46,552	12 May 2026	Direct
Jeffrey J. Cote	TSEOF	Ordinary Shares	Other	-48.2%			-42,484	45,699	12 May 2026	Direct
Joseph Alvarado	TSEOF	Ordinary Shares	Other	-44.9%			-42,484	52,187	12 May 2026	Direct
Klynne Johnson	TSEOF	Ordinary Shares	Other	-46.7%			-42,484	48,429	12 May 2026	Direct
Victoria Brifo	TSEOF	Ordinary Shares	Other	-51%			-42,484	40,741	12 May 2026	Direct
Matthew Farrell	TSEOF	Ordinary Shares	Other	-17%			-42,484	207,741	12 May 2026	Direct
Henri Steinmetz	TSEOF	Ordinary Shares	Other	-44.3%			-42,484	53,453	12 May 2026	Direct
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

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