F-SECURE CORPORATION STOCK EXCHANGE ANNOUNCEMENT Translation from Finnish April 4, 2008 at 16.10 ANNOUNCEMENT PURSUANT TO SECURITIES ACT CHAPTER 2, SECTION 10 F-Secure Corporation has been informed today by Osuuspankkikeskus Osk (identity 0242522-1) that OPK's holding and voting rights will go over one-twentieth (1/20). 1. The company: F-Secure Corporation 2. The date of change in holding: April 4, 2008 3. Exact proportion of voting rights and share capital in F-Secure Corporation: Totally 7,934,274 shares; 5.12% of voting rights and share capital. 4. Shareholder: Shareholders and their share of voting rights and of share capital. Shares of capital of votes OP-Rahastoyhtiön hallinnoimat rahastot, Y-tunnus 0743962-2 Pohjola Vakuutus Oy, 1458359-3 225.000 0,145 % 0,145 % A-Vakuutus Oy, 1715947-2 25.000 0,016 % 0,016 % OP-Delta, 1102395-3 2.994.930 1,931 % 1,931 % OP-Teknologia , 1601124-9 50.763 0,033 % 0,033 % OP-Focus , 1753298-6 1.244.424 0,802 % 0,802 % OP-Pohjola Pienyhtiöt, 1960678-2 650.000 0,419 % 0,419 % OP-Suomi Pienyhtiöt 1753300-6 2.744.157 1,769 % 1,769 % TOTALLY 7.934.274 5,115 % 5,115 % F-Secure Corporation Kimmo Alkio President & CEO Additional information: F-Secure Corporation Taneli Virtanen, CFO tel.358 9 2520 5655 DISTRIBUTION Helsinki Exchanges