X0303 4 2009-04-20 0 0000075129 OTTER TAIL CORP OTTR 0001180965 PARTAIN NATHAN I 215 S CASCADE ST FERGUS FALLS MN 56537-2801 1 0 0 0 Common Stock 2009-04-20 4 A 0 3600 A 17706.3459 D Common Stock 1600 I By IRA Stock Options (right to buy) 19.75 2001-04-10 2010-04-10 Common Stock 2000 2000 D Stock Options (right to buy) 26.25 2002-04-09 2011-04-09 Common Stock 2000 2000 D Shares of Common Stock acquired under the Corporation's Stock Incentive Plan, which is a grant of Restricted Stock. The 3,600 shares granted 4/20/2009 vest 25% yearly commencing 4/8/2010. This grant has a FMV of $22.15. Total direct holdings include shares jointly held with spouse at Merrill Lynch, shares held individually in the Dividend Reinvestment Plan and shares acquired individually pursuant to Restricted Stock Award distributions. Stock options vest in cumulative annual installments of 25% beginning the date shown. /s/ Nathan I Partain by Debra J Lill, Attorney-in-Fact 2009-04-21