ACCOUNTING POLICIES AND BASIS OF PRESENTATION	9 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]
ACCOUNTING POLICIES AND BASIS OF PRESENTATION	ACCOUNTING POLICIES AND BASIS OF PRESENTATION Compass Minerals International, Inc. (“CMI”), through its subsidiaries (collectively, the “Company”), is a leading global provider of essential minerals focused on safely delivering where and when it matters to help solve nature’s challenges for customers and communities. The Company’s salt products help keep roadways safe during winter weather and are used in numerous other consumer, industrial, chemical and agricultural applications. Its plant nutrition business is the leading North American producer of sulfate of potash (“SOP”), which is used in the production of specialty fertilizers for high-value crops and turf and helps improve the quality and yield of crops, while supporting sustainable agriculture. The Company’s principal products are salt, consisting of sodium chloride and magnesium chloride, and SOP. The Company’s production sites are located in the United States (“U.S.”), Canada and the United Kingdom (“UK”). The Company also provides records management services in the UK. Except where otherwise noted, references to North America include only the continental U.S. and Canada, and references to the UK include only England, Scotland and Wales. References to “Compass Minerals,” “our,” “us” and “we” refer to CMI and its consolidated subsidiaries. CMI is a holding company with no significant operations other than those of its wholly-owned subsidiaries. The consolidated financial statements include the accounts of CMI and its wholly-owned domestic and foreign subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. The accompanying Condensed Consolidated Balance Sheet as of September 30, 2025, which was derived from audited financial statements, and the unaudited condensed consolidated financial statements (“Condensed Consolidated Financial Statements”) have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete consolidated financial statements. As a result, these Condensed Consolidated Financial Statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2025. In the opinion of management, these interim financial statements reflect all adjustments, consisting of normal recurring adjustments considered necessary for a fair presentation of the Company’s financial position and results of operations. Accounting Pronouncements Issued Not Yet Adopted Income Tax Disclosures. In December 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which updates income tax disclosures by requiring consistent categories and additional disaggregation of information in the rate reconciliation and income taxes paid by jurisdiction. The ASU is effective for fiscal years beginning after December 15, 2024, and is effective for the Company beginning in the annual report for the fiscal year ended September 30, 2026. The amendments should be applied prospectively; however, retrospective application is permitted. The Company will adopt the disclosure requirements of ASU 2023-09 in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2026, which will result in additional disclosures related to income tax but will not impact the Company’s results of operations or financial position. Disaggregation of Income Statement Expenses. In November 2024, the FASB issued amended guidance related to disclosure of disaggregated expenses (“ASU 2024-03”). This amendment requires public business entities to provide detailed disclosures in the notes to financial statements disaggregating specific expense categories, including purchases of inventory, employee compensation, depreciation, depletion, and intangible asset amortization, as well as certain other disclosures to provide enhanced transparency into the nature and function of expenses. This guidance is effective for annual periods beginning with the Company’s annual report for the fiscal year ended September 30, 2028, and interim periods following annual adoption, with early adoption permitted. This guidance will be applied on a prospective basis with retrospective application permitted. Management is currently evaluating ASU 2024-03 to determine its impact on the Company’s disclosures. Interim Reporting. In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements (“ASU 2025-11”), to improve the guidance for interim reporting and clarify when that guidance is applicable. This ASU provides a comprehensive list of required interim disclosures and also requires entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU 2025-11 is effective for interim reporting periods within annual reporting periods beginning after December 15, 2027. For the Company, the guidance becomes effective in the first interim period of the fiscal year ended September 30, 2029. Early adoption is permitted. Management is currently evaluating ASU 2025-11 to determine its impact on the Company’s disclosures. Presentation In the Condensed Consolidated Statements of Cash Flows, the presentation of Principal payments to pay down term loan of $(191.3) million has been reclassified in the nine months ended June 30, 2025 to Principal payments on long-term debt to conform to current year presentation.

Compass Minerals International, Inc. (“CMI”), through its subsidiaries (collectively, the “Company”), is a leading global provider of essential minerals focused on safely delivering where and when it matters to help solve nature’s challenges for customers and communities. The Company’s salt products help keep roadways safe during winter weather and are used in numerous other consumer, industrial, chemical and agricultural applications. Its plant nutrition business is the leading North American producer of sulfate of potash (“SOP”), which is used in the production of specialty fertilizers for high-value crops and turf and helps improve the quality and yield of crops, while supporting sustainable agriculture. The Company’s principal products are salt, consisting of sodium chloride and magnesium chloride, and SOP. The Company’s production sites are located in the United States (“U.S.”), Canada and the United Kingdom (“UK”). The Company also provides records management services in the UK. Except where otherwise noted, references to North America include only the continental U.S. and Canada, and references to the UK include only England, Scotland and Wales. References to “Compass Minerals,” “our,” “us” and “we” refer to CMI and its consolidated subsidiaries.

CMI is a holding company with no significant operations other than those of its wholly-owned subsidiaries. The consolidated financial statements include the accounts of CMI and its wholly-owned domestic and foreign subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation.

The accompanying Condensed Consolidated Balance Sheet as of September 30, 2025, which was derived from audited financial statements, and the unaudited condensed consolidated financial statements (“Condensed Consolidated Financial Statements”) have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete consolidated financial statements. As a result, these Condensed Consolidated Financial Statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2025. In the opinion of management, these interim financial statements reflect all adjustments, consisting of normal recurring adjustments considered necessary for a fair presentation of the Company’s financial position and results of operations.

Income Tax Disclosures. In December 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which updates income tax disclosures by requiring consistent categories and additional disaggregation of information in the rate reconciliation and income taxes paid by jurisdiction. The ASU is effective for fiscal years beginning after December 15, 2024, and is effective for the Company beginning in the annual report for the fiscal year ended September 30, 2026. The amendments should be applied prospectively; however, retrospective application is permitted. The Company will adopt the disclosure requirements of ASU 2023-09 in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2026, which will result in additional disclosures related to income tax but will not impact the Company’s results of operations or financial position.

Disaggregation of Income Statement Expenses. In November 2024, the FASB issued amended guidance related to disclosure of disaggregated expenses (“ASU 2024-03”). This amendment requires public business entities to provide detailed disclosures in the notes to financial statements disaggregating specific expense categories, including purchases of inventory, employee compensation, depreciation, depletion, and intangible asset amortization, as well as certain other disclosures to provide enhanced transparency into the nature and function of expenses. This guidance is effective for annual periods beginning with the Company’s annual report for the fiscal year ended September 30, 2028, and interim periods following annual adoption, with early adoption permitted. This guidance will be applied on a prospective basis with retrospective application permitted. Management is currently evaluating ASU 2024-03 to determine its impact on the Company’s disclosures.

Interim Reporting. In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements (“ASU 2025-11”), to improve the guidance for interim reporting and clarify when that guidance is applicable. This ASU provides a comprehensive list of required interim disclosures and also requires entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU 2025-11 is effective for interim reporting periods within annual reporting periods beginning after December 15, 2027. For the Company, the guidance becomes effective in the first interim period of the fiscal year ended September 30, 2029. Early adoption is permitted. Management is currently evaluating ASU 2025-11 to determine its impact on the Company’s disclosures.

In the Condensed Consolidated Statements of Cash Flows, the presentation of Principal payments to pay down term loan of $(191.3) million has been reclassified in the nine months ended June 30, 2025 to Principal payments on long-term debt to conform to current year presentation.