X0306 4 2020-03-12 0001466593 Otter Tail Corp OTTR 0001639060 Abbott John S 215 S CASCADE ST FERGUS FALLS MN 56537-2801 1 Pres Varistar, Sr VP, M/I Plat Common Stock 2020-03-12 4 P 0 5000 41.21 A 5000 I by Trust Common Stock 19276 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $40.99-$41.25 inclusive. The reporting person undertakes to provide to Otter Tail Corporation, any security holder of Otter Tail Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote. Total indirect holdings are held in the name of the reporting person's Trust. Total direct holdings include shares acquired individually pursuant to Restricted Stock Awards and Performance Share Award distributions. /s/ John S Abott by Ella Leapaldt, Attorney-in-Fact 2020-03-16