Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ Quarterly Report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the quarterly ended March 31, 2021 or ☐ Transition Report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Commission File Number 0-53713 OTTER TAIL CORPORATION (Exact name of registrant as specified in its charter) Minnesota (State or other jurisdiction of incorporation or organizati ...

SIDOTI SPRING VIRTUAL INVESTOR CONFERENCE March 24-25, 2021 RGB COLORS FORWARD-LOOKING STATEMENT This presentation contains statements that may be considered forward-looking statements. The words "anticipate," "believe," "could," "estimate," "expect," "intend," "may," "outlook," "plan," "possible," "potential," "should," "will," "would" and similar words and expressions are intended to identify forward-looking statements. Such statements are based upon the current beliefs and expectations of management. For ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ Annual Report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the fiscal year ended December 31, 2020 or ☐ Transition Report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Commission File Number 0-53713 OTTER TAIL CORPORATION (Exact name of registrant as specified in its charter) Minnesota (State or other jurisdiction of incorporation or organiza ...

Otter Tail Corporation (NASDAQ:OTTR) Q4 2020 Earnings Conference Call February 16, 2021 11:00 AM ET Company Participants Loren Hanson - Investor Relations Chuck MacFarlane - President & Chief Executive Officer Kevin Moug - Senior Vice President & Chief Financial Officer Conference Call Participants Sophie Karp - KeyBanc Brian Russo - Sidoti Tate Sullivan - Maxim Group Operator Good morning, and welcome to Otter Tail Corporation's 2020 Earnings Conference Call. Today's call is being recorded and we will hold ...