BASIS OF PRESENTATION	6 Months Ended
Jun. 30, 2026
BASIS OF PRESENTATION
BASIS OF PRESENTATION	NOTE 1—BASIS OF PRESENTATION The unaudited interim condensed consolidated financial statements of Trinseo PLC and its subsidiaries (the “Company”) as of and for the periods ended June 30, 2026 and 2025 were prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and reflect all adjustments, consisting only of normal recurring adjustments, which, in the opinion of management, are considered necessary for the fair statement of the results for the periods presented. Because they cover interim periods, the statements and related notes to the financial statements do not include all disclosures normally provided in annual financial statements, and therefore, these statements should be read in conjunction with the 2025 audited consolidated financial statements included within the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (“SEC”) on March 13, 2026. The Company’s condensed consolidated financial statements presented herein reflect the latest estimates and assumptions made by management that affect the reported amounts and related disclosures as of and for the period ended June 30, 2026. However, actual results could differ from these estimates and assumptions. The December 31, 2025 condensed consolidated balance sheet data presented herein was derived from the Company’s December 31, 2025 audited consolidated financial statements but does not include all disclosures required by GAAP for annual periods. Current Bankruptcy Proceedings On May 26, 2026 (the “Petition Date”), Trinseo PLC and certain of its direct and indirect subsidiaries (Altuglas LLC, Aristech Surfaces LLC, Trinseo International Holding LLC, Trinseo Holding B.V., Trinseo Holding S.a r.l., Trinseo LLC, Trinseo Luxco Finance SPV S.a r.l., Trinseo LuxCo S.a r.l., Trinseo Materials Finance, Inc., Trinseo NA Finance LLC, Trinseo NA Finance SPV LLC, and Trinseo US Holding, Inc.) (collectively, the “Debtors”) filed voluntary petitions for relief under Chapter 11 of Title 11 of the United States Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the Southern District of Texas (the “Bankruptcy Court”), commencing the Company’s Chapter 11 cases (the “Chapter 11 Cases”). The Debtors continue to operate their businesses and manage their properties as debtors-in-possession pursuant to sections 1107 and 1108 of the Bankruptcy Code. As debtors-in-possession, the Debtors are generally authorized to operate their businesses in the ordinary course. The filing of the Chapter 11 Cases triggered the automatic stay under Section 362 of the Bankruptcy Code, which, among other things, prohibits the Company’s creditors from taking actions to collect on prepetition obligations or to exercise remedies with respect to such obligations, absent relief from the Bankruptcy Court. To ensure their ability to continue operating in the ordinary course of business, the Debtors have filed with the Bankruptcy Court a variety of motions seeking “first day” relief, including the authority to access cash collateral, continue using their cash management system, pay employee wages and benefits and pay vendors in the ordinary course of business. At a hearing held on May 27, 2026, the Bankruptcy Court generally approved the relief sought in these motions on an interim basis. Following subsequent hearings held on June 17, 2026, the Bankruptcy Court entered orders approving substantially all of the relief sought on a final basis. Prior to the Petition Date, the Company’s nonpayment of certain interest obligations beyond applicable grace periods constituted events of default under certain of its debt agreements and triggered cross-defaults under other financing arrangements. As a result of the Chapter 11 filings, enforcement of remedies by prepetition creditors with respect to such defaults is stayed. During the three months ended June 30, 2026, the Debtors transferred $13.4 million of cash into a separate escrow bank account administered by Kroll Restructuring Administration LLC, who on the Debtors' behalf will pay the allowed professional fee claims after notice from the Bankruptcy Court. The Debtors have continued to fund the escrow bank account weekly through the issuance date of these condensed consolidated financial statements. The funds held in the escrow account are classified as restricted cash, included within “Other current assets” in the Company’s condensed consolidated balance sheet. The Chapter 11 Cases were initiated to facilitate a comprehensive restructuring of the Company’s capital structure (the “Chapter 11 Restructuring Transactions”) through a joint prepackaged plan of reorganization (the “Plan”) pursuant to a Restructuring Support Agreement, dated May 13, 2026 (the “RSA”), entered into with certain holders of the Company’s funded indebtedness. Restructuring Support Agreement and Plan The RSA contemplates the implementation of the Plan, which provides for, among other things, the cancellation, discharge, and release of substantially all of the Company’s prepetition funded indebtedness, the issuance of consideration to eligible holders of such claims, including equity interests in the reorganized Company, cash, subscription rights and takeback debt instruments. Under the Plan general unsecured trade claims and other non-funded debt claims are expected to be unimpaired and paid in full in the ordinary course of business and existing equity interests are expected to be cancelled, extinguished, and of no further force or effect, and are not expected to receive any recovery. The Plan is supported by certain lenders holding substantial portions of the Company’s funded debt including, the Super HoldCo 1L Lenders holding approximately 98.0% of the aggregate outstanding principal amount of Super HoldCo 1L Claims under the Credit Agreement dated September 8, 2023 (as amended, the “2028 Refinance Credit Agreement”) and 100% of the OpCo Intercompany Term Loans; certain Revolving Credit Facility (“RCF”) Lenders holding approximately 100% of the aggregate outstanding principal amount of RCF Claims under the Credit Agreement dated January 17, 2025 (as amended, the “RCF Credit Agreement”); and certain OpCo 2028 Term Lenders holding approximately 57.2% of the aggregate outstanding principal amount of OpCo 2028 Term Loan Claims under the Credit Agreement dated September 6, 2017 (as amended, the “Credit Agreement”). The Super HoldCo 1L Claims contain portions of the aggregate outstanding principal amount of the senior secured term loan facility maturing in May 2028 (the “2028 Refinance Term Loans”) (as defined in the 2028 Refinance Credit Agreement). The RCF Claims contain portions of the super-priority revolving credit facility maturing in February 2028 (the “OpCo Super-Priority Revolver”) (as defined in the RCF Credit Agreement). The OpCo 2028 Term Loan Claims contain portions of the aggregate outstanding principal amount of the senior secured term loan B facility maturing in May 2028 (the “2028 Term Loan B”) (as defined in the Credit Agreement). Application of ASC 852, Reorganizations There have been no material changes from Note 2, Significant Accounting Policies, as described in the notes to the Company’s consolidated financial statements contained in the Company's 2025 Annual Report except for the application of Accounting Standard Codification (“ASC”) Topic 852 – Reorganizations. Beginning on the Petition Date, the Company began applying the provisions of ASC 852, Reorganizations. As part of the Chapter 11 Cases, persons and entities believing that they have claims or causes of action against the Debtors may file proofs of claim evidencing such claims. The Debtors have not yet set a bar date (deadline) for holders of claims to file proofs of claim. The Debtors have received numerous claims as of the date of this report. We expect that the Debtors may continue to receive a significant number of claims in the future. We are not aware of any claims that we currently expect will require a material adjustment to the accounts and balances as reported as of June 30, 2026. Accordingly, liabilities subject to compromise are reported separately in the condensed consolidated balance sheets; refer to Note 18, Liabilities Subject to Compromise, for additional details, and reorganization items, net are reported separately in the condensed consolidated statements of operations; refer to Note 19, Reorganization Items, Net, for additional details. Liabilities subject to compromise represent prepetition obligations of the Debtors that may be impacted by the Chapter 11 Cases. Liabilities subject to compromise are recorded at the expected amount of the total allowed claim, even if they may ultimately be settled for different amounts. The determination of how liabilities will ultimately be settled or treated cannot be made until approved by the Bankruptcy Court. Because the Company has not yet obtained approval by the Bankruptcy Court, there remains uncertainty with respect to the ability of our creditors, including our secured and unsecured debt holders, to recover the full amount of their claims against us. As a result, all prepetition secured and unsecured debt instruments have been classified as liabilities subject to compromise in our condensed consolidated balance sheets as of June 30, 2026 along with any related accrued interest payable balance. Under the Bankruptcy Code, the Debtors may assume, modify, assign or reject certain executory contracts and unexpired leases, including, without limitation, leases of real property and equipment, subject to the approval of the Bankruptcy Court and certain other conditions. Although the Debtors do not intend to modify, assign or reject any of these agreements, and received approval from the Bankruptcy Court on June 17, 2026 to continue processing all lease payments, the Debtors’ lease liabilities were classified as liabilities subject to compromise in the condensed consolidated balance sheets as of June 30, 2026. The amounts in Note 19 are preliminary and may be subject to future adjustments as a result of, among other things, the possibility or occurrence of certain Bankruptcy Court actions, further developments with respect to disputed claims, and/or any payments by us of amounts classified as liabilities subject to compromise, which may be allowed in certain limited circumstances. Accordingly, the amounts ultimately allowed by the Bankruptcy Court may differ materially from amounts recorded in the accompanying condensed consolidated financial statements. Reorganization items, net represent amounts incurred or realized as a direct result of the Chapter 11 Cases and are reported separately in the condensed consolidated statements of operations. As a result, the Company’s financial statements distinguish transactions and events directly associated with the reorganization from the ongoing operations of the business; refer to Note 19, Reorganization Items, Net, for additional details. Status of the Chapter 11 Cases The Company solicited votes on the Plan prior to the Petition Date. As of the filing of this Quarterly Report, the Plan had not become effective. The effectiveness of the Plan remains subject to confirmation by the Bankruptcy Court and satisfaction or waiver of various closing conditions. The effectiveness of the Plan and the Company’s emergence from Chapter 11 are subject to several conditions, including final judgment by the Bankruptcy Court in ongoing litigation related to the Chapter 11 Cases, approval and confirmation of the Plan by the Bankruptcy Court, satisfaction of milestones and other conditions set forth in the RSA, receipt of required regulatory approvals, including approval by the High Court of Ireland, the Federal Trade Commission and other regulators, where applicable, and completion of debtor-in-possession and exit financing arrangements. The Company currently expects to emerge from Chapter 11 prior to the end of 2026; however, the timing and outcome of the Chapter 11 Cases, including confirmation and consummation of the Plan, remain subject to significant risks and uncertainties. Going Concern In accordance with ASC 205-40, Going Concern, the Company evaluated whether conditions and events raise substantial doubt about its ability to continue as a going concern within one year after the issuance of these condensed consolidated financial statements. The condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As of June 30, 2026, the Company had liquidity of $186.7 million and an accumulated deficit of $1,574.8 million and used cash in operations of $348.2 million during the six months ended June 30, 2026. The Company expects continued operating losses and significant cash outflows from operating activities in the near term. Current macroeconomic and geopolitical conditions, including inflation, and ongoing conflicts (such as the Russia-Ukraine war and military conflict in Iran), continue to create significant uncertainty in the broader business environment. These external factors have contributed to weaker demand in many of our end markets, significant volatility in raw material prices, and supply chain disruptions that are expected to continue to have a material adverse effect on the Company's financial performance and liquidity forecasts. Absent the consummation of the Chapter 11 Restructuring Transactions, significant debt maturities would occur in 2028, including the 2028 Refinance Term Loans, the 2028 Term Loan B, the A/R Facility, and the OpCo Super-Priority Revolver. As a result of these factors, the Company concluded that substantial doubt about its ability to continue as a going concern existed as of the issuance of the prior Form 10-K and continues to exist within one year after the issuance of these condensed consolidated financial statements. New York Stock Exchange Delisting Notification On March 2, 2026, we received written notice (the “Notice”) from the New York Stock Exchange (the “NYSE”) that they determined to commence proceedings to delist the Company’s ordinary shares and on March 18, 2026 the NYSE filed a Form 25 with the SEC to delist the Company’s ordinary shares from the NYSE. The delisting became effective ten days following the filing of Form 25.

BASIS OF PRESENTATION

6 Months Ended

Jun. 30, 2026

NOTE 1—BASIS OF PRESENTATION

The unaudited interim condensed consolidated financial statements of Trinseo PLC and its subsidiaries (the “Company”) as of and for the periods ended June 30, 2026 and 2025 were prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and reflect all adjustments, consisting only of normal recurring adjustments, which, in the opinion of management, are considered necessary for the fair statement of the results for the periods presented. Because they cover interim periods, the statements and related notes to the financial statements do not include all disclosures normally provided in annual financial statements, and therefore, these statements should be read in conjunction with the 2025 audited consolidated financial statements included within the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (“SEC”) on March 13, 2026.

The Company’s condensed consolidated financial statements presented herein reflect the latest estimates and assumptions made by management that affect the reported amounts and related disclosures as of and for the period ended June 30, 2026. However, actual results could differ from these estimates and assumptions.

The December 31, 2025 condensed consolidated balance sheet data presented herein was derived from the Company’s December 31, 2025 audited consolidated financial statements but does not include all disclosures required by GAAP for annual periods.

Current Bankruptcy Proceedings

On May 26, 2026 (the “Petition Date”), Trinseo PLC and certain of its direct and indirect subsidiaries (Altuglas LLC, Aristech Surfaces LLC, Trinseo International Holding LLC, Trinseo Holding B.V., Trinseo Holding S.a r.l., Trinseo LLC, Trinseo Luxco Finance SPV S.a r.l., Trinseo LuxCo S.a r.l., Trinseo Materials Finance, Inc., Trinseo NA Finance LLC, Trinseo NA Finance SPV LLC, and Trinseo US Holding, Inc.) (collectively, the “Debtors”) filed voluntary petitions for relief under Chapter 11 of Title 11 of the United States Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the Southern District of Texas (the “Bankruptcy Court”), commencing the Company’s Chapter 11 cases (the “Chapter 11 Cases”).

The Debtors continue to operate their businesses and manage their properties as debtors-in-possession pursuant to sections 1107 and 1108 of the Bankruptcy Code. As debtors-in-possession, the Debtors are generally authorized to operate their businesses in the ordinary course.

The filing of the Chapter 11 Cases triggered the automatic stay under Section 362 of the Bankruptcy Code, which, among other things, prohibits the Company’s creditors from taking actions to collect on prepetition obligations or to exercise remedies with respect to such obligations, absent relief from the Bankruptcy Court. To ensure their ability to continue operating in the ordinary course of business, the Debtors have filed with the Bankruptcy Court a variety of motions seeking “first day” relief, including the authority to access cash collateral, continue using their cash management system, pay employee wages and benefits and pay vendors in the ordinary course of business. At a hearing held on May 27, 2026, the Bankruptcy Court generally approved the relief sought in these motions on an interim basis. Following subsequent hearings held on June 17, 2026, the Bankruptcy Court entered orders approving substantially all of the relief sought on a final basis.

Prior to the Petition Date, the Company’s nonpayment of certain interest obligations beyond applicable grace periods constituted events of default under certain of its debt agreements and triggered cross-defaults under other financing arrangements. As a result of the Chapter 11 filings, enforcement of remedies by prepetition creditors with respect to such defaults is stayed.

During the three months ended June 30, 2026, the Debtors transferred $13.4 million of cash into a separate escrow

bank account administered by Kroll Restructuring Administration LLC, who on the Debtors' behalf will pay the allowed professional fee claims after notice from the Bankruptcy Court. The Debtors have continued to fund the escrow bank account weekly through the issuance date of these condensed consolidated financial statements. The funds held in the escrow account are classified as restricted cash, included within “Other current assets” in the Company’s condensed consolidated balance sheet.

The Chapter 11 Cases were initiated to facilitate a comprehensive restructuring of the Company’s capital structure (the “Chapter 11 Restructuring Transactions”) through a joint prepackaged plan of reorganization (the “Plan”) pursuant to a Restructuring Support Agreement, dated May 13, 2026 (the “RSA”), entered into with certain holders of the Company’s funded indebtedness.

Restructuring Support Agreement and Plan

The RSA contemplates the implementation of the Plan, which provides for, among other things, the cancellation, discharge, and release of substantially all of the Company’s prepetition funded indebtedness, the issuance of consideration to eligible holders of such claims, including equity interests in the reorganized Company, cash, subscription rights and takeback debt instruments.

Under the Plan general unsecured trade claims and other non-funded debt claims are expected to be unimpaired and paid in full in the ordinary course of business and existing equity interests are expected to be cancelled, extinguished, and of no further force or effect, and are not expected to receive any recovery.

The Plan is supported by certain lenders holding substantial portions of the Company’s funded debt including, the Super HoldCo 1L Lenders holding approximately 98.0% of the aggregate outstanding principal amount of Super HoldCo 1L Claims under the Credit Agreement dated September 8, 2023 (as amended, the “2028 Refinance Credit Agreement”) and 100% of the OpCo Intercompany Term Loans; certain Revolving Credit Facility (“RCF”) Lenders holding approximately 100% of the aggregate outstanding principal amount of RCF Claims under the Credit Agreement dated January 17, 2025 (as amended, the “RCF Credit Agreement”); and certain OpCo 2028 Term Lenders holding approximately 57.2% of the aggregate outstanding principal amount of OpCo 2028 Term Loan Claims under the Credit Agreement dated September 6, 2017 (as amended, the “Credit Agreement”).

The Super HoldCo 1L Claims contain portions of the aggregate outstanding principal amount of the senior secured term loan facility maturing in May 2028 (the “2028 Refinance Term Loans”) (as defined in the 2028 Refinance Credit Agreement). The RCF Claims contain portions of the super-priority revolving credit facility maturing in February 2028 (the “OpCo Super-Priority Revolver”) (as defined in the RCF Credit Agreement). The OpCo 2028 Term Loan Claims contain portions of the aggregate outstanding principal amount of the senior secured term loan B facility maturing in May 2028 (the “2028 Term Loan B”) (as defined in the Credit Agreement).

Application of ASC 852, Reorganizations

There have been no material changes from Note 2, Significant Accounting Policies, as described in the notes to the Company’s consolidated financial statements contained in the Company's 2025 Annual Report except for the application of Accounting Standard Codification (“ASC”) Topic 852 – Reorganizations. Beginning on the Petition Date, the Company began applying the provisions of ASC 852, Reorganizations.

As part of the Chapter 11 Cases, persons and entities believing that they have claims or causes of action against the Debtors may file proofs of claim evidencing such claims. The Debtors have not yet set a bar date (deadline) for holders of claims to file proofs of claim. The Debtors have received numerous claims as of the date of this report. We expect that the Debtors may continue to receive a significant number of claims in the future. We are not aware of any claims that we currently expect will require a material adjustment to the accounts and balances as reported as of June 30, 2026.

Accordingly, liabilities subject to compromise are reported separately in the condensed consolidated balance sheets; refer to Note 18, Liabilities Subject to Compromise, for additional details, and reorganization items, net are reported separately in the condensed consolidated statements of operations; refer to Note 19, Reorganization Items, Net, for additional details.

Liabilities subject to compromise represent prepetition obligations of the Debtors that may be impacted by the Chapter 11 Cases. Liabilities subject to compromise are recorded at the expected amount of the total allowed claim, even

if they may ultimately be settled for different amounts.

The determination of how liabilities will ultimately be settled or treated cannot be made until approved by the Bankruptcy Court. Because the Company has not yet obtained approval by the Bankruptcy Court, there remains uncertainty with respect to the ability of our creditors, including our secured and unsecured debt holders, to recover the full amount of their claims against us. As a result, all prepetition secured and unsecured debt instruments have been classified as liabilities subject to compromise in our condensed consolidated balance sheets as of June 30, 2026 along with any related accrued interest payable balance. Under the Bankruptcy Code, the Debtors may assume, modify, assign or reject certain executory contracts and unexpired leases, including, without limitation, leases of real property and equipment, subject to the approval of the Bankruptcy Court and certain other conditions. Although the Debtors do not intend to modify, assign or reject any of these agreements, and received approval from the Bankruptcy Court on June 17, 2026 to continue processing all lease payments, the Debtors’ lease liabilities were classified as liabilities subject to compromise in the condensed consolidated balance sheets as of June 30, 2026.

The amounts in Note 19 are preliminary and may be subject to future adjustments as a result of, among other things, the possibility or occurrence of certain Bankruptcy Court actions, further developments with respect to disputed claims, and/or any payments by us of amounts classified as liabilities subject to compromise, which may be allowed in certain limited circumstances. Accordingly, the amounts ultimately allowed by the Bankruptcy Court may differ materially from amounts recorded in the accompanying condensed consolidated financial statements.

Reorganization items, net represent amounts incurred or realized as a direct result of the Chapter 11 Cases and are reported separately in the condensed consolidated statements of operations. As a result, the Company’s financial statements distinguish transactions and events directly associated with the reorganization from the ongoing operations of the business; refer to Note 19, Reorganization Items, Net, for additional details.

Status of the Chapter 11 Cases

The Company solicited votes on the Plan prior to the Petition Date. As of the filing of this Quarterly Report, the Plan had not become effective. The effectiveness of the Plan remains subject to confirmation by the Bankruptcy Court and satisfaction or waiver of various closing conditions.

The effectiveness of the Plan and the Company’s emergence from Chapter 11 are subject to several conditions, including final judgment by the Bankruptcy Court in ongoing litigation related to the Chapter 11 Cases, approval and confirmation of the Plan by the Bankruptcy Court, satisfaction of milestones and other conditions set forth in the RSA, receipt of required regulatory approvals, including approval by the High Court of Ireland, the Federal Trade Commission and other regulators, where applicable, and completion of debtor-in-possession and exit financing arrangements.

The Company currently expects to emerge from Chapter 11 prior to the end of 2026; however, the timing and outcome of the Chapter 11 Cases, including confirmation and consummation of the Plan, remain subject to significant risks and uncertainties.

Going Concern

In accordance with ASC 205-40, Going Concern, the Company evaluated whether conditions and events raise substantial doubt about its ability to continue as a going concern within one year after the issuance of these condensed consolidated financial statements.

The condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As of June 30, 2026, the Company had liquidity of $186.7 million and an accumulated deficit of $1,574.8 million and used cash in operations of $348.2 million during the six months ended June 30, 2026. The Company expects continued operating losses and significant cash outflows from operating activities in the near term. Current macroeconomic and geopolitical conditions, including inflation, and ongoing conflicts (such as the Russia-Ukraine war and military conflict in Iran), continue to create significant uncertainty in the broader business environment. These external factors have contributed to weaker demand in many of our end markets, significant volatility in raw material prices, and supply chain disruptions that are expected to continue to have a material adverse effect on the Company's financial performance and liquidity forecasts.

Absent the consummation of the Chapter 11 Restructuring Transactions, significant debt maturities would occur in

2028, including the 2028 Refinance Term Loans, the 2028 Term Loan B, the A/R Facility, and the OpCo Super-Priority Revolver.

As a result of these factors, the Company concluded that substantial doubt about its ability to continue as a going concern existed as of the issuance of the prior Form 10-K and continues to exist within one year after the issuance of these condensed consolidated financial statements.

New York Stock Exchange Delisting Notification

On March 2, 2026, we received written notice (the “Notice”) from the New York Stock Exchange (the “NYSE”) that they determined to commence proceedings to delist the Company’s ordinary shares and on March 18, 2026 the NYSE filed a Form 25 with the SEC to delist the Company’s ordinary shares from the NYSE. The delisting became effective ten days following the filing of Form 25.