X0306 4 2017-04-08 0001466593 Otter Tail Corp OTTR 0001605621 ROGELSTAD TIMOTHY J 215 S CASCADE ST FERGUS FALLS MN 56537-2801 1 Sr VP, Elect Plat, Pres OTP Common Stock 2017-04-08 4 M 0 250 A 10216.141 D Common Stock 2017-04-08 4 F 0 85 38.075 D 10131.141 D Common Stock 2017-04-08 4 F 0 152 38.075 D 9979.141 D Common Stock 2434.4876 I ESOP Restricted Stock 2017-04-08 4 M 0 250 0 D 2017-04-08 2017-04-08 Common Stock 250 0 D Restricted STock Units 2016-02-06 Common Stock 900 900 D Restricted Stock 2017-02-06 Common Stock 1800 1800 D Restricted Stock 2018-02-06 Common Stock 1700 1700 D The reporting person receives one share of Common Stock for each restricted stock unit that vests. Grant of Restricted Stock Units. On 4/8/2017, 85 shares of Common Stock were withheld by the Corporation to pay taxes due upon vesting of restricted stock units, exempt pursuant to Rule 16b-3(e). Grant of Restricted Stock. On 4/8/2017, 152 shares of Common Stock were withheld by the Corporation to pay taxes due upon vesting of the restricted stock, exempt pursuant to Rule 16b-3(e). Total direct holdings include shares held in Dividend Reinvestment Plan, shares held jointly with spouse that were acquired through the Employee Stock Purchase Plan and shares acquired pursuant to Restricted Stock Awards and Restricted Stock Units. Each restricted stock unit represents a contingent right to receive one share of Otter Tail Corporation Common Stock. The restricted stock units vest in four equal annual installments beginning February 6, 2016. The restricted stock units vest in four equal annual installments beginning February 6,2017. The restricted stock units vest in four equal annual installments beginning February 6,2018. /s/ Timothy J Rogelstad by Ella J Leapaldt 2017-04-11