X0202 4 2006-04-10 0 0000075129 OTTER TAIL CORP OTTR 0001191483 ERICKSON JOHN D 215 S CASCADE ST FERGUS FALLS MN 56537-2801 0 1 0 0 President & CEO Common Stock 2006-04-10 4 F 0 7824 28.235 D 9000 D Grants of Restricted Stock. On 4/10/2006, 7,824 shares were withheld by the Corporation to pay taxes due upon vesting of restricted stock, exempt pursuant to Rule 16b-3(e). 9,000 shares remain restricted. See below for other holdings: 1. Direct holding of 106.0121 shares held in the Dividend Reinvestment Plan. 2. Direct holding of 7,806.5609 shares held in the Employee Stock Purchase Plan. 3. Direct holding of 40,303 shares which no longer carries the restriction. 4. Indirect holding of 4,981.6009 shares held by ESOP. 5. 16,000 stock options with expiration date of 2/22/2009. 6. 25,000 stock options with expiration date of 4/9/2010. 7. 75,000 stock options with expiration date of 4/8/2011. /s/ John D Erickson by Debra J Lill -POA 2006-04-12