Quarterly Report for Quarter Ending September 30, 2025 (Form 10-Q)

Management's Discussion and Analysis of Financial Condition and Results of Operations

2025 Year-to-Date Highlights

During the three and nine months ended September 30, 2025, Trinseo recognized net loss of $109.7 million and $294.2 million, respectively, and Adjusted EBITDA of $30.4 million and $136.8 million, respectively. Adjusted EBITDA for the quarter and year was impacted by continued low levels of demand due to persistent market uncertainty, which was partially offset by lower fixed costs through strategic savings initiatives. The Company has access to capital resources through the financings available under our debt structure.

Refer to the discussion below for further information and refer to "Non-GAAP Performance Measures" for discussion of our use of non-GAAP measures in evaluating our performance and a reconciliation of these measures. Other highlights for the year are described below.

Strategic Operational and Liquidity Initiatives

On October 2, 2025, the Company, upon authorization from the Board of Directors, approved a restructuring plan to permanently close our methyl methacrylate ("MMA") production operations in Rho, Italy and our acetone cyanohydrin ("ACH") production operations in Porto Marghera, Italy (the "MMA Restructuring Plan"). The MMA Restructuring Plan is intended to streamline our MMA production network and exit underperforming assets. Moving forward, we will source all MMA feedstock from third-party producers. The Company expects the MMA Restructuring Plan actions to commence in the fourth quarter of 2025, subject to the satisfaction of local law requirements. However, the actual timing and costs of the MMA Restructuring Plan may differ from the Company's current expectations and estimates and such differences may be material since these charges are subject to ongoing negotiations with works councils, industrial associations and government authorities. The Company expects to record total pre-tax restructuring charges of $80.0 million to $100.0 million, principally comprised of $3.0 million to $6.0 million of employee-related costs, $40.0 million to $46.0 million of asset-related charges and $37.0 million to $48.0 million related to exiting production activities, including contract terminations, demolition and decommissioning. The anticipated future cash payments associated with these charges are expected to be approximately $40.0 million to $50.0 million with substantially all payments expected to be made by the end of 2028. The MMA Restructuring Plan is expected to deliver approximately $20.0 million of annualized profitability improvement beginning in 2026.

Dividend Suspension

On October 3, 2025, the Company's Board of Directors indefinitely suspended the quarterly dividend of $0.01 per share, effective immediately, which is expected to save approximately $1.5 million annually.

New Financing Arrangements

On December 9, 2024, the Company executed a Transaction Support Agreement (the "TSA") with certain supporting creditors, including holders of the Company's 2025 Notes and 2029 Senior Notes, 2028 Refinance Credit Agreement lenders, lenders under the 2026 Revolving Facility and certain term lenders under the Credit Agreement. The supporting creditors agreed to support a series of transactions to refinance near-term maturities, provide additional operating liquidity, extend the Company's nearest debt maturity to 2028, and capture discount from an exchange of its 2029 Senior Notes.

On January 17, 2025, the Company completed a series of transactions contemplated by the TSA, including an offer to exchange any outstanding 5.125% senior notes due 2029 (the "2029 Senior Notes") in exchange for new 7.625% Second Lien Senior Secured Notes due 2029 (the "2029 Refinance Senior Notes"). The 2029 Refinance Senior Notes with an aggregate principal amount of approximately $379.5 million were issued in exchange for a total of approximately $446.5 million aggregate principal amount of the 2029 Senior Notes, or 99.88% of the outstanding principal. The 2029 Refinance Senior Notes bear interest at a rate of 7.625%, of which: (i) from the Settlement Date until and through the sixth semiannual interest payment date following the Settlement Date, 5.125% will be payable in cash and 2.50% will be payable in-kind either by increasing the principal amount of the outstanding 2029 Refinance Senior Notes, or, at the Company's option, in cash; and (ii) thereafter, the entire 7.625% per annum will be payable in cash. Interest on the 2029 Refinance Senior Notes will be paid semiannually on February 15 and August 15 of each year, commencing on August 15, 2025. The 2029 Refinance Senior Notes will mature on May 3, 2029. On March 20, 2025,

the remaining 2029 Senior Notes, including principal, redemption premium, and interest thereon, was paid in full in the amount of $0.5 million, upon which redemption the related indenture was satisfied and discharged.

Additionally, the Company issued a $115.0 million new tranche of loans under the certain credit agreement dated September 8, 2023 (as amended, the "2028 Refinance Credit Agreement"), on substantially similar terms to the existing term loans under the 2028 Refinance Credit Agreement. The proceeds of this tranche of loans were used to redeem all of the $115.0 million aggregate principal amount outstanding of the 5.375% senior notes due 2025 (the "2025 Notes").

The Company also executed a new credit agreement to provide a new super priority revolving credit facility (the "OpCo Super-Priority Revolver") in an initial aggregate principal committed amount of $300.0 million with a February 2028 maturity date. This OpCo Super-Priority Revolver has a revised springing covenant, a liquidity covenant, an anti-cash hoarding covenant, and is available to be drawn upon immediately. The OpCo Super-Priority Revolver replaced the Company's existing revolving credit facility due to mature in May 2026.

Polycarbonate technology license and production equipment transactions

On November 13, 2024, the Company announced it entered into agreements to supply a polycarbonate technology license and proprietary polycarbonate production equipment in Stade, Germany to a wholly owned subsidiary of Deepak for use in India for a value of approximately $52.5 million. During the first quarter of 2025, the Company completed its performance obligations on the delivery of the technology license and recognized $26.0 million in "Other Expense (Income), Net" within the Polymer Solutions segment in the condensed consolidated statements of operations.

Exploration for Divestiture of Americas Styrenics

In March 2024, the Company announced it commenced a sale process for the Company's interest in Americas Styrenics, via the initiation of an ownership exit provision in the joint venture agreement. Trinseo and Chevron Phillips Chemical Company LP, co-owners of Americas Styrenics, have decided to pursue a joint sale process. While we, along with our partner, remain committed to sell Americas Styrenics, with our focus being to maximize value, given recent volatility in equity and debt markets, a signing may not occur until there are improvements in those underlying markets.

Recent Developments

As disclosed in Part I, Item 1A: Risk Factors, of our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, our business is subject to risks related to the impact of global trade conflicts and the imposition of tariffs by the United States or other countries including those with China, Canada, and the European Union. Although we generally manufacture products and procure raw materials in the regions where our products are sold, these tariffs may negatively impact demand and increase some product costs. Tariffs or other trade restrictions may lead to continuing uncertainty and volatility in U.S. and global financial and economic conditions and commodity markets, declining consumer confidence, significant inflation and diminished expectations for the economy, and ultimately reduced demand for our customers' products resulting in proportionate reductions in demand for our products. Such conditions could have a material adverse impact on our business, results of operations and cash flows. We continue to closely monitor as well as engage with our customers and suppliers to analyze how tariffs could impact our business. We are not able to predict whether such tariffs will be permanent, whether new tariffs will be implemented, or which jurisdictions would be impacted. Uncertainty over global tariffs has and may continue to delay purchasing decisions by our customers as they assess the impact of such trade policies on their business. Further changes in trade policy, trade restrictions, tariffs, or other governmental action has the potential to adversely impact our costs, including prices of raw materials, or demand for our products or our customers' products, which in turn could adversely impact our business, financial condition and results of operations.

Results of Operations

Results of Operations for the Three and Nine Months Ended September 30, 2025 and 2024

Three Months Ended - September 30, 2025 vs. September 30, 2024

Net Sales

Net sales decreased 14% year-over-year, primarily driven by a 7% decrease from lower sales volumes across all business segments, primarily due to continued end market demand weakness, and a 9% decrease from lower pricing. The decreases were partially offset by a 2% increase from favorable foreign exchange rate impacts.

Cost of Sales

The 10% decrease in cost of sales was primarily attributable to an 8% decrease due to lower pricing and a 5% decrease due to lower volumes. These decreases were partially offset by a 3% increase from foreign exchange rate impacts.

Gross Profit

The $43.2 million decrease in gross profit was primarily due to both lower volumes and margins. Lower margins were particularly in Polymer Solutions and Latex Binders due to competitive price pressure particularly in Europe. See the segment discussion below for further information.

Selling, General and Administrative Expenses (SG&A)

The $33.8 million, or 35%, decrease in SG&A was primarily due to a $24.8 million decrease in costs associated with the Company's restructuring plan, a $5.5 million decrease in employee compensation related accruals, and a $3.4 million decrease in the Company's depreciation and amortization expenses.

Equity in Earnings of Unconsolidated Affiliate

The decrease in equity earnings from Americas Styrenics of $6.4 million was mainly due to costs associated with an unplanned outage.

Interest Expense, Net

The decrease in interest expense, net of $1.7 million, or 2%, was primarily attributable to a decrease in market interest rates on our variable rate debt, specifically the 2028 Refinance Loans and the 2028 Term Loan B. Refer to Note 10 in the condensed consolidated financial statements for further information.

Other Expense (Income), Net

Other expense, net for the three months ended September 30, 2025 was $2.6 million, which was primarily driven by $0.8 million of expense related to the non-service cost components of net periodic benefit cost and net foreign exchange transaction losses of $0.4 million.

Other income, net for the three months ended September 30, 2024 was $1.4 million, which was primarily driven by net foreign exchange transaction gains of $2.5 million, related to our balance sheet hedging program, and $0.2 million of income related to the non-service cost components of net periodic benefit cost.

Provision for (Benefit from) Income Taxes

Provision for income taxes for the three months ended September 30, 2025 totaled $8.3 million, resulting in an effective tax rate of (8.2)%. Provision for income taxes for the three months ended September 30, 2024 totaled $3.4 million, resulting in an effective tax rate of (4.1)%.

The increase in provision for income taxes for the three months ended September 30, 2025 is primarily driven by the geographical mix of earnings.

Nine Months Ended - September 30, 2025 vs. September 30, 2024

Net Sales

Net sales decreased 14% year-over-year, primarily driven by a 10% decrease from lower sales volumes across all business segments, due to continued end market demand weakness and intentionally reducing volumes or exiting low-margin businesses, particularly in Polymer Solutions, Latex Binders, and MMA markets within Engineered Materials, to optimize plant operations and sales mix and a 4% decrease due to lower pricing.

Cost of Sales

The 12% decrease in cost of sales was primarily attributable to an 8% decrease due to lower sales volumes and a 5% decrease due to lower pricing. These decreases were partially offset by an increase of 1% from favorable foreign exchange rate impacts.

Gross Profit

The $71.8 million decrease in gross profit was primarily due to lower volumes, partially offset by our cost reduction initiatives. See the segment discussion below for further information.

Selling, General and Administrative Expenses (SG&A)

The $4.9 million, or 2%, decrease in SG&A was primarily due to a $27.1 million increase in costs associated with the Company's debt refinancing transaction executed in the first quarter and a $7.1 million increase in due to pre-tax gains made on various assets sold in the previous year. These increases were offset by a $19.9 million decrease in costs associated with the Company's restructuring plan and a $11.2 million decrease in employee compensation related accruals.

Equity in Earnings of Unconsolidated Affiliate

The decrease in equity earnings from Americas Styrenics of $21.8 million was due to lower polystyrene volumes and higher raw material input costs, as well as unplanned outages.

Interest Expense, Net

The increase in interest expense, net of $6.7 million, or 3%, was primarily attributable to the increased year-over-year usage of our short-term borrowing under the Accounts Receivable Securitization Facility and the OpCo Super-Priority Revolver and the additional principal generated from the margin on the executed payment in kind elections ("PIK Interest Election"). These increases were partially offset by a decrease in market interest rates on our variable rate debt, specifically the 2028 Refinance Loans and the 2028 Term Loan B. Refer to Note 10 in the condensed consolidated financial statements for further information.

Other Expense (Income), Net

Other income, net for the nine months ended September 30, 2025 was $20.6 million, which was primarily driven by $26.0 million of license income for polycarbonate technology. The licensing income was partially offset by net foreign exchange transaction losses of $1.6 million and $1.7 million of expense related to the non-service cost components of net periodic benefit cost.

Other income, net for the nine months ended September 30, 2024 was $0.9 million, which was primarily driven by a gain of$3.5 million related to the sale of certain European emission certifications the Company no longer intends to utilize and net foreign exchange transaction gains of $1.6 million, related to our balance sheet hedging program. These gains were partially offset by $1.9 million of expense related to the non-service cost components of net periodic benefit cost.

Provision for (Benefit from) Income Taxes

Provision for income taxes for the nine months ended September 30, 2025 totaled $17.4 million, resulting in an effective tax rate of (6.3)%. Provision for income taxes for the nine months ended September 30, 2024 totaled $29.1 million, resulting in an effective tax rate of (14.4)%.

The decrease in provision for income taxes for the nine months ended September 30, 2025 is primarily driven by the establishment of a valuation allowance in the amount of $13.7 million for the Company's China Subsidiary recorded in the second quarter 2024 and an increase in its reserve in the amount of $6.6 million for unrecognized tax benefits related to its ongoing tax examination in China recorded in the second and third quarters of 2024, partially offset by the geographical mix of earnings.

Outlook

Fourth quarter Adjusted EBITDA is expected to be comparable to third quarter 2025 as we expect a continuation of the challenging economic and geopolitical conditions through the end of the year. We expect an improvement in the results of Americas Styrenics, offset by seasonal lower demand in all segments. Free cash flow in the fourth quarter is expected to be sequentially better due to a working capital release from year-end seasonality. The Company remains focused on enhancing free cash flow in both the near and long term through disciplined working capital management, restructuring initiatives, and other actions.

Selected Segment Information

The following sections describe net sales, Adjusted EBITDA, and Adjusted EBITDA margin by segment for the three and nine months ended September 30, 2025 and 2024. Inter-segment sales have been eliminated. Refer to Note 16 in the condensed consolidated financial statements for further information on our segments, as well as for a detailed definition of Adjusted EBITDA and a reconciliation of income from continuing operations before income taxes to segment Adjusted EBITDA. Prior period segment amounts herein have been recast in conjunction with the Company's segment realignment that occurred during the fourth quarter of 2024, as described in Note 16 of the condensed consolidated financial statements.

Engineered Materials Segment

Our Engineered Materials segment consists of rigid thermoplastic compounds and blends products sold into high growth and high value applications in markets such as consumer electronics, medical and automotive, as well as soft

thermoplastic elastomers ("TPEs") products which are sold into markets such as footwear and automotive. The Engineered Materials segment also includes polymethyl methacrylates ("PMMA") and MMA products, which are sold into a variety of applications including automotive, building and construction, medical, consumer electronics, and wellness, among others.

Three Months Ended - September 30, 2025 vs. September 30, 2024

The 7% decrease in net sales was primarily attributable to an 8% decrease due to lower sales volumes, particularly in medical applications. This was partially offset by higher volumes in PMMA resins and a 1% increase due to favorable foreign exchange rate impacts.

Adjusted EBITDA increased $0.3 million, due to increases of $6.0 million, or 18%, from higher margins and $3.7 million, or 11%, from lower fixed costs. These increases were partially offset by a $9.4 million, or 28%, decrease due to lower sales volumes.

Nine Months Ended - September 30, 2025 vs. September 30, 2024

The 6% decrease in net sales was primarily attributable to an 8% decrease due to lower sales volumes across our end market applications, especially in automotive and building and construction. This was partially offset by a 2% increase due to higher pricing from raw material pass-through and mix improvements.

Adjusted EBITDA increased $14.6 million, of which $30.6 million, or 40%, was due to higher margins resulting from mix improvements, lower natural gas hedge losses, more normalized MMA market dynamics in the first quarter and a $7.3 million, or 10%, increase from lower fixed costs. These increases were partially offset by a decrease of $23.3 million, or 31%, due to lower sales volumes from continued end market demand weakness.

Latex Binders Segment

Our Latex Binders segment produces styrene-butadiene latex ("SB latex") and other latex polymers and binders primarily for coated paper and packaging board, carpet and artificial turf backings, as well as a broad range of performance latex binders products, including SB latex, styrene-acrylate latex ("SA latex"), and vinylidene chloride latex for coatings, adhesives, sealants, and elastomers ("CASE") applications.

Three Months Ended - September 30, 2025 vs. September 30, 2024

The 18% decrease in net sales was primarily attributable to an 8% decrease due to lower sales volumes in paper and board and a 12% decrease from lower price due to pricing pressures in Europe and Asia. The decreases were partially offset by higher volumes in CASE and battery binders plus a 2% increase due to favorable foreign exchange rate impacts.

The $8.7 million, or 34%, decrease in Adjusted EBITDA was primarily due to a $6.1 million, or 24%, decline in sales volumes in paper and board, particularly in Europe and a $5.9 million, or 23%, decrease due to lower margins. These decreases were partially offset by an increase of $2.9 million, or 11%, from lower fixed costs and an increase of $0.4 million, or 2%, from favorable foreign exchange rate impacts.

Nine Months Ended - September 30, 2025 vs. September 30, 2024

The 17% decrease in net sales was primarily attributable to a 12% decrease in sales volumes driven by lower paper and board in Europe and Asia and a 5% decrease from lower global prices across most end applications.

The $18.6 million, or 24%, decrease in Adjusted EBITDA was primarily due to a $22.2 million, or 29%, decrease in sales volumes, mostly in Europe paper and board, and a $4.3 million, or 6%, decrease due to lower margins. These were partially offset by an increase of $7.1 million, or 9%, attributable to lower fixed costs, an increase of $0.5 million, or 1%, from favorable foreign exchange rate impacts, and an increase of $0.3 million, or 1% from favorable currency impacts.

Polymer Solutions Segment

Our Polymer Solutions segment consists of a variety of polymers, the majority of which are for building and construction applications. The segment includes our mass acrylonitrile butadiene styrene ("ABS"), styrene-acrylonitrile ("SAN"), and polystyrene businesses, as well as our polycarbonate technology.

Three Months Ended - September 30, 2025 vs. September 30, 2024

Net sales decreased by 18% year-over-year, primarily due to a 15% decrease from lower pricing and a 6% decrease from lower sales volumes in ABS and unfavorable mix. The decrease was partially offset by a 3% increase due to favorable foreign exchange rate impacts.

The $19.3 million, or 82%, decrease in Adjusted EBITDA was primarily due to a $13.5 million, or 58%, decrease from pricing, mainly in polystyrene, and a $10.0 million, or 42%, decrease in ABS sales volumes and unfavorable mix. The decreases were partially offset by a $3.6million, or 16%, increase from lower fixed costs from the exit of polycarbonate production in Stade, Germany and a $0.6 million, or 2%, increase from favorable foreign exchange rate impacts.

Nine Months Ended - September 30, 2025 vs. September 30, 2024

Net sales decreased by 19% year-over-year, primarily due to an 11% decrease from lower sales volumes and a 9% decrease from lower pricing. The reductions were primarily in polycarbonate from portfolio optimization actions and in polystyrene and ABS from continued weak market conditions. The decreases were partially offset by a 1% increase from favorable foreign exchange rate impacts.

The $14.9 million, or 22%, decrease in Adjusted EBITDA was primarily due to a $38.4 million, or 56%, decrease from lower sales volumes and a $38.3 million, or 56%, decrease from lower pricing. These decreases were partially offset by a $35.8 million increase, or 52%, from lower fixed costs from the exit of polycarbonate production in Stade, Germanypaired with a $26.0 million, or 38%, increase from polycarbonate technology licensing income.

Americas Styrenics Segment

This segment consists solely of the equity earnings from our 50%-owned joint venture, Americas Styrenics, a producer of both styrene monomer and polystyrene in North America. Styrene monomer is a basic building block of plastics and a key input to many of the Company's products, as well as a key raw material for the production of polystyrene. Major applications for the polystyrene products Americas Styrenics produces include appliances, food packaging, food service disposables, consumer electronics, and building and construction materials.

*The results of this segment are comprised entirely of earnings from Americas Styrenics, our equity method investment. As such, Adjusted EBITDA related to this segment is included within "Equity in earnings of unconsolidated affiliates" in the condensed consolidated statements of operations.

Three Months Ended - September 30, 2025 vs. September 30, 2024

The decrease in Adjusted EBITDA was mainly due to costs associated with an unplanned outage.

Nine Months Ended - September 30, 2025 vs. September 30, 2024

The decrease in Adjusted EBITDA was mainly due to lower polystyrene volumes and unplanned outages.

Non-GAAP Performance Measures

We present Adjusted EBITDA as a non-GAAP financial performance measure, which we define as income from continuing operations before interest expense, net; provision for income taxes; depreciation and amortization expense; loss on extinguishment of long-term debt and certain debt issuance costs; asset impairment charges; gains or losses on the dispositions of businesses and assets and related legal costs; restructuring charges; acquisition related costs, certain strategic initiatives and other items. In doing so, we are providing management, investors, and credit rating agencies with an indicator of our ongoing performance and business trends, removing the impact of transactions and events that we would not consider a part of our core operations.

There are limitations to using the financial performance measures such as Adjusted EBITDA. This performance measure is not intended to represent net income or other measures of financial performance. As such, it should not be used as an alternative to net income as an indicator of operating performance. Other companies in our industry may define Adjusted EBITDA differently than we do. As a result, it may be difficult to use this or similarly-named financial measures that other companies may use, to compare the performance of those companies to our performance. We compensate for these limitations by providing a reconciliation of this performance measure to our net income, which is determined in accordance with GAAP.

Adjusted EBITDA is calculated as follows for the three and nine months ended September 30, 2025 and 2024:

Other items for the three and nine months ended September 30, 2024 primarily relate to fees incurred in conjunction with Synthos litigation, certain strategic initiatives, as well as costs related to our transition to a new enterprise resource planning system.

Liquidity and Capital Resources

Cash Flows

The table below summarizes our primary sources and uses of cash for the nine months ended September 30, 2025 and 2024. We have derived the summarized cash flow information from our unaudited financial statements.

Operating Activities

Net cash used in operating activities during the nine months ended September 30, 2025 totaled $125.0 million, which included a $9.1 million decrease in working capital, including the impact of $26.3 million in expenses related to refinancing that were not eligible for capitalization as deferred financing costs.

Net cash used in operating activities during the nine months ended September 30, 2024 totaled $99.3 million, which included a $5.7 million decrease in working capital and $15.0 million of dividends received from Americas Styrenics. Cash provided by operations during the third quarter 2024 was $8.8 million, a sequential improvement of $50.7 million compared to second quarter 2024 as a result of targeted working capital and other actions, including deferring interest payments through the PIK Interest Election.

Investing Activities

Net cash used in investing activities during the nine months ended September 30, 2025 totaled $35.0 million, which was primarily attributable to capital expenditures.

Net cash used in investing activities during the nine months ended September 30, 2024 totaled $33.9 million, which was primarily attributable to capital expenditures of $42.1 million offset by proceeds from the sale of other assets of $8.2 million.

Financing Activities

Net cash provided by financing activities during the three months ended September 30, 2025 totaled $56.0 million. During the nine months the Company drew $140.0 million and $150.0 million in proceeds and repaid $75.0 million and $120.0 million from the Accounts Receivable Securitization Facility and OpCo Super-Priority Revolver, respectively, principally related to funding working capital through the quarter. This activity also included the issuance of additional 2028 Refinance Term Loans ($115.0 million of aggregate principal) in exchange for the redemption of the 2025 Senior Notes ($115.0 million reduction in aggregate principal), $19.8 million of debt issuance costs that met the criteria for deferred financing charges, $1.2 million of dividends paid, and $2.8 million of net repayments of short-term borrowings.

Net cash provided by financing activities during the nine months ended September 30, 2024 totaled $40.7 million. During the nine months the Company drew $438.2 million in proceeds from the A/R Facility, and repaid $363.2 million, principally related to funding working capital through the quarter. This activity was partially offset by $13.7 million in debt repayments, $1.3 million of dividends paid, and $14.0 million of net repayments of short-term borrowings.

Free Cash Flow

We use Free Cash Flow as a non-GAAP measure to evaluate and discuss the Company's liquidity position and results. Free Cash Flow is defined as cash from operating activities, less capital expenditures. We believe that Free Cash Flow provides an indicator of the Company's ongoing ability to generate cash through core operations, as it excludes the cash impacts of various financing transactions as well as cash flows from business combinations that are not considered organic in nature. We also believe that Free Cash Flow provides management and investors with useful analytical indicator of our ability to service our indebtedness, pay dividends (when declared), and meet our ongoing cash obligations.

Free Cash Flow is not intended to represent cash flows from operations as defined by GAAP, and therefore, should not be used as an alternative for that measure. Other companies in our industry may define Free Cash Flow differently than we do. As a result, it may be difficult to use this or similarly-named financial measures that other companies may use, to compare the liquidity and cash generation of those companies to our own. We compensate for these limitations by providing a reconciliation to cash provided by operating activities from continuing operations, which is determined in accordance with GAAP.

Refer to the discussion above for significant impacts to cash used in operating activities for the nine months ended September 30, 2025 and 2024.

Capital Resources and Liquidity

We require cash principally for day-to-day operations, to finance capital investments and other initiatives, to purchase materials, and to service our outstanding indebtedness. Our sources of liquidity include cash on hand, cash flow from operations from continuing operations, and amounts available under the OpCo Super-Priority Revolver and the Accounts Receivable Securitization Facility (discussed further below).

The 2028 Refinance Credit Agreement requires the Company to comply with customary affirmative, negative and financial covenants, and contains events of default including (i) relating toa change of control or (ii) failure to maintain at least $100.0 million of Liquidity at the end of any calendar month, and (iii) a cross default to the Credit Agreement. If an event of default occurs, the Term Lenders will be entitled to take various actions, including the acceleration of amounts due under the 2028 Refinance Term Loans. Liquidity is defined substantially similar under both the OpCo Super-Priority Revolver and the 2028 Refinance Credit Agreement, as a combination of cash and cash equivalents held at certain of the Company's restricted subsidiaries as well as the funds available for borrowing under both the OpCo Super-Priority Revolver and the Accounts Receivable Securitization Facility, subject to certain restrictions outlined in the 2028 Refinance Credit Agreement.

In addition, the OpCo Super-Priority Revolver's anti-cash hoarding covenant requires repayment of existing borrowings under the OpCo Super-Priority Revolver of the excess amount of cash and cash equivalents held by loan parties over $100.0 million or the excess cash and cash equivalents held by non-loan parties over $50.0 million. As of September 30, 2025, the Company was in compliance with all debt covenant requirements under all debt agreements.

As of September 30, 2025, the Company had Liquidity of $346.4 million, comprised of $102.2 million of cash and cash equivalents and approximately $244.2 million of funds available for borrowing under both the OpCo Super-Priority Revolver and the Accounts Receivable Securitization Facility, $236.8 million and $7.4 million, respectively.

As of September 30, 2025 and December 31, 2024, we had $2,573.0 million and $2,448.4 million, respectively, in outstanding indebtedness and $248.2 million and $267.3 million, respectively, in working capital. In addition, as of September 30, 2025 and December 31, 2024, we had $84.7 million and $107.7 million, respectively, of foreign cash and cash equivalents on our balance sheet, outside of Ireland, our country of domicile, all of which is readily convertible into other foreign currencies, including the U.S. dollar. Our intention is not to permanently reinvest our foreign cash and cash equivalents. Accordingly, we record deferred income tax liabilities related to the unremitted earnings of our subsidiaries.

The following table outlines our outstanding indebtedness as of September 30, 2025 and December 31, 2024 and the associated interest expense, including amortization of deferred financing fees and debt discounts. Effective interest rates for the borrowings included in the table below exclude the impact of deferred financing fee amortization, certain other fees charged to interest expense (such as fees for unused commitment fees during the period), and the impacts of derivatives designated as hedging instruments. For definitions of capitalized terms not included herein, refer to our Annual Report on Form 10-K ("Annual Report").

Our 2025 Senior Notes were issued under an indenture executed in 2017 (the "2025 Notes Indenture"), included $115.0 million aggregate principal amount of 5.375% senior notes that mature on September 1, 2025. On January 17, 2025, the remaining 2025 Senior Notes, including principal and interest thereon, were redeemed, upon which redemption the related indenture was satisfied and discharged. In exchange, the Company amended the 2028 Refinance Credit Agreement to provide for an additional senior secured term loan facility of $115.0 million original principal bearing interest at a rate per annum equal to Term SOFR plus 8.50%, subject to a 3.00% SOFR floor.

Our 2029 Senior Notes, as issued under the indenture executed in 2021 (the "2029 Notes Indenture"), included $447.0 million aggregate principal amount of 5.125% senior notes that mature on April 1, 2029. On January 17, 2025, the Company redeemed $446.5 million of aggregate principal in exchange for the issuance of the second lien 2029 Refinance Senior Notes. Our 2029 Refinance Senior Notes, as issued under the indenture executed in 2025 (the "2L Note Indenture"), include $379.5 million aggregate principal amount of 7.625% senior notes that mature on May 3, 2029. Interest on the 2029 Refinance Senior Notes is payable semi-annually on February 15 and August 15 of each year, commencing on August 15, 2025. On March 20, 2025, the remaining 2029 Senior Notes, including principal, redemption premium, and interest thereon, were redeemed for $0.5 million, upon which redemption the related indenture was satisfied and discharged.

The 2028 Refinance Term Loans (with original principal of $1,077.3 million, maturing in May 2028) require scheduled quarterly payments in amounts equal to 0.25% of the original principal plus the additional $115.0 million of principal issued in January 2025. The 2028 Refinance Term Loans bear interest at a rate per annum equal to Term SOFR (as defined in the 2028 Refinance Credit Agreement) plus 8.50%, subject to a 3.00% SOFR floor, were issued at a 3.0% original issue discount.

The Senior Credit Facility includes our 2028 Term Loan B (with original principal of $750.0 million, maturing in May 2028), which requires scheduled quarterly payments in amounts equal to 0.25% of the original principal. The stated interest rate on our 2028 Term Loan B is SOFR plus 2.50% (subject to a 0.00% SOFR floor) and was issued at a 0.5% original issue discount.

During the nine months ended September 30, 2025, the Company made $5.6 million and $8.4 million of net principal payments on the 2028 Term Loan B and the 2028 Refinance Term Loans, respectively, with an additional $18.3 million of scheduled future payments classified within current debt on the Company's consolidated balance sheet as of September 30, 2025 related to both the 2028 Refinance Term Loans and the 2028 Term Loan B.

Under the terms of the 2028 Refinance Credit Agreement, through September 8, 2025, the Company may, at its discretion, make a payment in kind election ("PIK Interest Election") to convert a portion of the quarterly interest margin payable to principal, and the converted principal is subject to an additional 1.00% margin. Third quarter 2025 is the final period the Company is able to use the PIK Interest Election for the 2028 Refinance Term Loans. Under the terms of the 2L Note Indenture, the Company will make a PIK Interest Election for 2.50% of the annual interest payable for each of its first six semi-annual interest payments starting on August 15, 2025.

During the nine months ended September 30, 2025, the Company executed the PIK Elections and deferred $46.3 million of interest payable and capitalized as long-term debt. During the year ended December 31, 2024, the Company deferred payment of $33.9 million of interest payable and capitalized as long-term debt.

As of September 30, 2025, under the OpCo Super-Priority Revolver, the Company had a capacity of $300.0 million with capacity of $60.0 million under the letter of credit subfacility. As of September 30, 2025, the Company had funds available for borrowing of $236.8 million (net of the applicable $33.2 million outstanding letters of credit as defined in the secured credit agreement). Additionally, the Company was required to pay a quarterly commitment fee for any unused commitments equal to 0.375% per annum.

We also continue to maintain an accounts receivable securitization facility that matures in January 2028, with an optional one-year extension (the "Accounts Receivable Securitization Facility"). The facility has a borrowing limit of $150.0 million and bears interest at a rate per annum equal to Adjusted Term SOFR or EURIBOR (each as defined in the Accounts Receivable Securitization Facilitycredit agreement, subject to a 1.00% floor), depending on the borrowing currency, plus a margin of 4.75%, and the Company incurs interest on a minimum of $75.0 million of advances, irrespective of actual amounts outstanding. It contains standard representations, warranties, and covenants, as well as standard events of default, including those relating to cross-default to the Company's other material indebtedness and may be terminated at any time, subject to a 1.00% call premium prior to January 2027.

As of September 30, 2025, there was $140.0 million outstanding under the facility and the Company had $147.4 million of accounts receivable available to support this facility, based on the pool of eligible accounts receivable, and had $7.4 million additional funds available for borrowing. During the quarter ended September 30, 2025, the Company drew $10.0 million and repaid $20.0 million from the facility. On occasion, the accounts receivable available to support the facility fails to meet the amount required to reach the maximum borrowing capacity of $150.0 million. In the event

of any shortfall, the Company manages liquidity through a combination of the available cash and cash equivalents, available Accounts Receivable Securitization Facility, and the Revolver as needed.

Our ability to raise additional financing and our borrowing costs may be impacted by short- and long-term debt ratings assigned by independent rating agencies, which are based, in significant part, on our performance as measured by certain credit metrics such as interest coverage and leverage ratios.

We and our subsidiaries, affiliates or significant shareholders may from time to time seek to retire or purchase our outstanding debt through cash purchases in the open market, privately negotiated transactions, exchange transactions or otherwise. Such repurchases or exchanges, if any, will depend on prevailing market conditions, our liquidity requirements, contractual restrictions, and other factors. The amounts involved may be material.

Trinseo Holding S.á r.l. (formerly Trinseo Materials Operating S.C.A.) and Trinseo Materials Finance, Inc. ("Borrowers" under our Senior Credit Facility), and Trinseo Luxco Finance SPV S.á r.l. and Trinseo NA Finance SPV LLC (the "Issuers" of our 2029 Refinance Senior Notes and Borrowers under the 2028 Refinance Credit Agreement) are dependent upon the cash generation and receipt of distributions and dividends or other payments from our subsidiaries and joint venture in order to satisfy their debt obligations. There are no known significant restrictions by third parties on the ability of subsidiaries of the Company to disburse or dividend funds to the Issuers and the Borrowers in order to satisfy these obligations. However, as the Company's subsidiaries are located in a variety of jurisdictions, the Company can give no assurances that our subsidiaries will not face transfer restrictions in the future due to regulatory or other reasons beyond our control.

The Senior Credit Facility, Refinance Credit Agreement and 2L Note Indenture also limit the ability of the Borrowers and Issuers, respectively, to pay dividends or make other distributions to Trinseo PLC, which could then be used to make distributions to shareholders. During the three months ended September 30, 2025, the Company did not declare dividends and the Board of Directors voted to indefinitely suspend the Company's quarterly dividend.

Cash flows from operations have been, and may continue to be, adversely affected by various risks and uncertainties, including, but not limited to, those described in Part I, Item 1A, "Risk Factors," of our Annual Report on Form 10-K for the year ended December 31, 2024. Macroeconomic conditions-including uncertainty related to global tariffs, elevated interest rates, and geopolitical conditions-have resulted in lower demand and earnings. These factors may negatively impact our liquidity and ability to access capital resources.

We have recurring net losses and negative operating cash flows. Although our strategic initiatives are focused on achieving sustainable profitability-including the liquidity and cost-reduction measures described above-we expect to continue operating at a net loss for the near future.

Based on our current business forecasts, we believe we have near term access to sufficient liquidity, comprised of cash and cash equivalent balances and borrowings available under our OpCo Super Priority Revolver and Accounts Receivable Securitization Facility, to manage through the ongoing impact of the macroeconomic challenges, lower demand, supply constraints and supplier cash in advance requirements for at least the next twelve months. The Company continues to focus on cost savings measures and disciplined working capital management to position the Company for future economic recovery.

The Company's ability to meet its liquidity requirements will depend on the achievement of planned Adjusted EBITDA and operating cash flow targets, as well as effective cost and working capital management over the next twelve months. Our ability to meet liquidity requirements longer term remains dependent on recovery in the Company's end markets. However, our cash resources may be depleted more rapidly than anticipated due to deteriorating demand, further economic uncertainty, unforeseen expenditures, or other factors beyond our control. In the event the Company is unable to achieve its planned Adjusted EBITDA and operating cash flows or maintain minimum liquidity requirements, it could have a material adverse impact on our access to liquidity, results of operation and financial condition.

Contractual Obligations and Commercial Commitments

There have been no material revisions outside the ordinary course of business to our contractual obligations as described within "Management's Discussion and Analysis of Financial Condition and Results of Operations - Contractual Obligations and Commercial Commitments" within our Annual Report.

Critical Accounting Policies and Estimates

Our unaudited interim condensed consolidated financial statements are based on the selection and application of significant accounting policies. The preparation of unaudited interim condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and revenues and expenses at the date of and during the reporting period. Actual results could differ from those estimates. However, we are not currently aware of any reasonably likely events or circumstances that would result in materially different results.

We describe our significant accounting policies in Note 2, Basis of Presentation and Summary of Significant Accounting Policies, in the Notes to Consolidated Financial Statements included in our Annual Report, while we discuss our critical accounting policies and estimates in "Management's Discussion and Analysis of Financial Condition and Results of Operations" within our Annual Report. There have been no material revisions to the significant accounting policies or critical accounting policies and estimates as filed in our Annual Report.

Off-Balance Sheet Arrangements

We do not have any off-balance sheet arrangements.

Recent Accounting Pronouncements

We describe the impact of recent accounting pronouncements in Note 2 of our condensed consolidated financial statements, included elsewhere within this Quarterly Report.