X0202 4 2006-04-10 0 0000075129 OTTER TAIL CORP OTTR 0001191498 LIEBE ARVID R 215 S CASCADE ST FERGUS FALLS MN 56537-2801 1 0 0 0 Common Stock 2006-04-10 4 A 0 2200 28.235 A 4100 D Shares of Common Stock acquired under the Corporation's Stock Incentive Plan, which is a grant of Restricted Stock. The 2,200 shares granted 4/10/06 have a grant price of $28.235 and vest at 25% yearly beginning 4/8/07. See below for other holdings: 1. Direct holding of 1,397.3476 shares held in the Dividend Reinvestment Plan. 2. Direct holding of 1,200 shares which no longer carries the restriction. 3. Indirect holding of 31.3165 shares held by his children in custodian accounts. 4. Indirect holding of 2,975.0430 shares held by an IRA. 5. 1,413.7140 stock units with no specific expiration date. 6. 2,000 stock options with expiration date of 4/8/2011. /s/ Arvid R Liebe by Debra J Lill -POA 2006-04-12