September 14, 2010 at 14.35 Announcement pursuant to Securities Act Chapter 2, Section 10 F-Secure Corporation has today been informed by OP-Keskus osk that the holding of OP-Keskus in F-Secure has fallen below 5% (1/20) and is currently 4.9%, after being, on the basis of their previous announcement, 5.013% on September 7, 2010. 1. The company: F-Secure Corporation 2. The date of change in holding: September 14, 2010 3. Shareholders and their proportions of shares and voting rights in F-Secure Corporation: Pohjola Vakuutus Oy, register number 1458359-3 125.000 shares, 0.079% A-Vakuutus Oy, 1715947-2 18.968 shares, 0.012% OP-Henkivakuutus, 1030059-2 186.498 shares, 0.118% OP-Rahastoyhtiö's funds, 0743962-2 OP-Delta, 1102395-3 4.281.016 shares, 2.719% OP-Suomi Pienyhtiöt, 1753300-6 2.580.418 shares, 1.639% OP-Focus, 1753298-6 524.303 shares, 0.333% Totally 7.716.203 shares, 4.9% of share capital and voting rights. 4. Shareholder's name and register number: OP-Keskus osk, 0242522-1 F-Secure Oyj Taneli Virtanen CFO For more information, please contact: F-Secure Corporation Mervi Pohjoisaho, IR, tel. +358 40 535 8989