X0202 4 2006-08-15 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 2006-08-15 4 S 0 1134 29.40 D 66 D Common Stock 2006-08-15 4 S 0 66 29.41 D 0 D Shares of Common Stock acquired under the Corporation's Stock Incentive Plan, which is a grant of Restricted Stock. These vested shares were sold by Wells Fargo Investments. See below for other holdings: 1. Direct holding of 1,469.0677 shares held in the Dividend Reinvestment Plan. 2. Direct holding of 4,100 shares which is a grant of Restricted Stock. 3. Indirect holding of 3,037.1530 shares held by an IRA. 4. 1,428.4723 stock units with no specific expiration date. 5. 2,000 stock options with expiration date of 4/8/2011. /s/ Arvid R Liebe by Debra J Lill -POA 2006-08-16