FORM10-Q (Mark One)☒Quarterly Report pursuant to Sec on 13 or 15(d) of the Securi es Exchange Act of 1934 ☐Transi on Report pursuant to Sec on 13 or 15(d) of the Securi es Exchange Act of 1934 Commission File Number0-53713 OTTER TAIL CORPORATION (Exact name of registrant as specified in its charter) (State or other jurisdic on of incorpora on or organiza on) 215 South Cascade Street,Box 496,Fergus Falls,Minnesota(Address of principal execu ve offices) Registrant's telephone number, including area code:866-410-8780 Securi es registered pursuant to Sec on 12(b) of the Act: Indicate by check mark whether the registrant (1) hasfiled all reports required to befiled by Sec on 13 or 15(d) of the Securi es Exchange Act of 1934 during thepreceding 12 months (or for such shorter period that the registrant was required tofile such reports), and (2) has been subject to suchfiling requirements for the past Indicate by check mark whether the registrant has submi ed electronically every Interac ve Data File required to be submi ed pursuant to Rule 405 of Regula on S-Tduring the preceding 12 months (or for such shorter period that the registrant was required to submit suchfiles).Yes☑No☐ Indicate by check mark whether the registrant is a large acceleratedfiler, an acceleratedfiler, a non-acceleratedfiler or a smaller repor ng company. See thedefini ons of “large acceleratedfiler,” “acceleratedfiler,” “smaller repor ng company” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Checkone): Large Accelerated Filer☑Accelerated Filer☐Non-Accelerated Filer☐Smaller Repor ng Company☐Emerging Growth Company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transi on period for complying with any new or revisedfinancial accoun ng standards provided pursuant to Sec on 13(a) of the Exchange Act☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes☐No☑ Indicate the number of shares outstanding of each of the registrant's classes of common stock, as of the latest prac cable date:41,904,370CommonShares ($5 par value) asof April30, 2025. DEFINITIONS The following abbrevia ons or acronyms are used in the text. FORWARD-LOOKING INFORMATION This Quarterly Report on Form 10-Q contains forward-looking statements within the meaning of the Private Securi es Li ga onReform Act of 1995 (the PSLRA). When used in this Form 10-Q and in futurefilings by O er Tail Corpora on (the Company) with theSecuri es and Exchange Commission (SEC), in the Company’s press releases and in oral statements, words such as “an cipate,”“believe,” “can," "could,” “es mate,” “expect,” "future," "goal," “intend,” "likely," “may,” “outlook,” “plan,” “possible,” “poten al,”"predict," "probable," "projected," “should,” "target," “will,” “would” or similar expressions are intended to iden fy forward-lookingstatements within the meaning of the PSLRA. Such statements are based on current expecta ons and assump ons and entail variousrisks and uncertain es that could cause actual results to differ materially from those expressed in such forward-looking statements.The Company’s risks and uncertain es include, among other things, uncertainty of future investments and capital expenditures; ratebase levels and rate base growth; long-term investment risk; seasonal weather pa erns and extreme weather events; counterpartycredit risk; future business volumes with key customers; reduc ons in our credit ra ngs; our ability to access capital markets onfavorable terms; assump ons and costs rela ng to funding our employee benefit plans; our subsidiaries’ ability to make dividendpayments; cyber security threats or data breaches; the impact of government legisla on and regula on including foreign trade andenvironmental policies; health and safety laws and regula ons; the impact of climate change including compliance with legisla veand regulatory changes to address climate change; opera onal and economic risks associated with our electric genera ng and PART I. FINANCIAL INFORMATION OTTER TAIL CORPORATIONCONSOLIDATED BALANCE SHEETS (unaudited) Table of Contents OTTER TAIL CORPORATION CONDENSED NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (unaudited) 1.Summary of Significant Accoun ng Policies Overview O er Tail Corpora on (OTC) and its subsidiaries (collec vely, the "Company", "us", "our" or "we") form a diverse, mul -pla ormbusiness consis ng of a ver cally integrated, regulated u lity with genera on, transmission and distribu on facili es complementedby manufacturing businesses providing metal fabrica on for custom machine parts and metal components, manufacturing of Basis of Presenta onThe unaudited consolidatedfinancial statements included herein have been prepared pursuant to the rules and regula ons of the SEC for interim repor ng. Accordingly, they do not include all the informa on and footnotes required by generally acceptedaccou