Otter Tail Corp

CONDENSED NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (unaudited)

1. Summary of Significant Accounting Policies

Overview

Otter Tail Corporation (OTC) and its subsidiaries (collectively, the "Company", "us", "our", or "we") form a diverse, multi-platform business consisting of a vertically integrated, regulated utility with generation, transmission, and distribution facilities complemented by manufacturing businesses providing metal fabrication for custom machine parts and metal components, manufacturing of extruded and thermoformed plastic products, and manufacturing of polyvinyl chloride (PVC) pipe products. We classify our business into three segments: Electric, Manufacturing, and Plastics. Note 2 includes an additional description of the segments and financial information regarding each segment.

Basis of Presentation

The unaudited consolidated financial statements included herein have been prepared pursuant to the rules and regulations of the SEC for interim reporting. Accordingly, they do not include all information and footnotes required by generally accepted accounting principles. In the opinion of management, we have included all adjustments, including normal recurring accruals, necessary for a fair presentation of the consolidated financial statements for the periods presented. The consolidated financial statements and condensed notes thereto should be read in conjunction with the consolidated financial statements and notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025.

Because of the seasonality of our businesses and other factors, earnings for the three and nine months ended September 30, 2026 should not be taken as an indication of earnings for all or any part of the balance of the current year or as an indication of earnings for future years.

Use of Estimates

We use estimates based on the best information available in recording transactions and balances resulting from business operations. As better information becomes available or actual amounts are known, the recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates.

Recent Accounting Pronouncements

Disaggregated Income Statement Expenses. In November 2024, the Financial Accounting Standards Board (FASB) issued authoritative guidance codified in Accounting Standards Codification (ASC) 220, Income Statement—Reporting Comprehensive Income, which will require additional disclosures of certain costs and expenses within the notes to the financial statements. The new standard is effective for our annual periods beginning in 2027 and interim periods beginning in the first quarter of fiscal 2028 and can be applied on either a prospective or retrospective basis. Early adoption of the new standard is permitted. We anticipate adopting the updated standard in our Form 10-K for the year ending December 31, 2027.

Government Grants. In December 2025, the FASB issued authoritative guidance codified in ASC 832, Government Grants, which adds guidance on the recognition, measurement, and presentation of government grants. The new guidance is effective for our annual periods beginning in 2029, including interim periods within that fiscal year, and can be applied on a modified prospective, modified retrospective, or full retrospective basis. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.