Exhibit 21.1
SUBSIDIARIES OF TRINSEO PLC
AS OF DECEMBER 31, 2025
Entity Name | Jurisdiction |
1. Trinseo Belgium B.V. | Belgium |
2. Trinseo Operating Belgium B.V. | Belgium |
3. Trinseo Canada ULC | Canada |
4. Styron Synthetic Materials (Shanghai) Company Limited | China |
5. Trinseo Polymers (Zhangjiagang) Company Limited | China |
6. Altuglas International Denmark A/S | Denmark |
7. Trinseo Suomi Oy | Finland |
8. Altuglas International SAS | France |
9. Trinseo France S.A.S. | France |
10. Trinseo Deutschland Anlagengesellschaft mbH | Germany |
11. Trinseo Deutschland GmbH | Germany |
12. Trinseo (Hong Kong) Limited | Hong Kong |
13. Trinseo Materials (Hong Kong) Limited | Hong Kong |
14. Trinseo India Trading Private Limited | India |
15. PT Trinseo Materials Indonesia | Indonesia |
16. PT Trinseo Operating Indonesia | Indonesia |
17. Trinseo Finance Ireland Unlimited Company | Ireland |
18. Trinseo Ireland Global IHB Limited | Ireland |
19. Trinseo Ireland Holdings Limited | Ireland |
20. Trinseo Services Ireland Limited | Ireland |
21. A.P.I. Applicazioni Plastiche Industriali S.p.A. | Italy |
22. Altuglas S.r.l. | Italy |
23. Trinseo Italia S.R.L. | Italy |
24. Trinseo Japan Y.K. | Japan |
25. Trinseo Korea Ltd. | Korea |
26. Trinseo Holding S.à r.l. | Luxembourg |
27. Trinseo Luxco S.à r.l. | Luxembourg |
28. Trinseo Luxco Finance SPV S.à r.l. | Luxembourg |
29. Altuglas Mexico, S.A. de C.V. | Mexico |
30. Trinseo de México S. de R.L. de C.V. | Mexico |
31. Heathland B.V. | The Netherlands |
32. Styron Netherlands Holding Company B.V. | The Netherlands |
33. Trinseo Holding B.V. | The Netherlands |
34. Trinseo Netherlands B.V. | The Netherlands |
35. Trinseo Holdings Asia Pte. Ltd. | Singapore |
36. Trinseo Singapore Pte. Ltd. | Singapore |
37. Trinseo Sverige AB | Sweden |
38. Trinseo Europe GmbH | Switzerland |
39. Trinseo Export GmbH | Switzerland |
40. Taiwan Trinseo Limited | Taiwan |
41. Trinseo Kimya Ticaret Limited Şirketi | Turkey |
42. Trinseo UK Limited | England and Wales |
43. Altuglas LLC | USA – Delaware |
44. Americas Styrenics LLC1 | USA – Delaware |
45. Trinseo LLC | USA – Delaware |
46. Trinseo Materials Finance, Inc. | USA – Delaware |
47. Trinseo NA Finance LLC | USA – Delaware |
48. Trinseo NA Finance SPV LLC | USA – Delaware |
49. Trinseo U.S. Holding, Inc. | USA – Delaware |
50. Trinseo U.S. Receivables Company SPV LLC | USA – Delaware |
51. Aristech Surfaces LLC | USA – Kentucky |
1 Represents a joint venture company of which the registrant indirectly owns 50% of the voting equity.