Ahlstrom's announcement under Securities Markets Act (chapter 2, section 10) regarding a change in shareholding

2 oktober 2012 Ahlstrom Corporation STOCK EXCHANGE RELEASE October 2, 2012 at 16.40 Ahlstrom Corporation has received an announcement from Vimpu Intressenter Ab, dated October 2, 2012, regarding a change in the shareholding of the said shareholder. According to the announcement, Vimpu Intressenter's shareholding in Ahlstrom Corporation has on October 2, 2012, has exceeded 5% (1/20) of the share capital and voting rights of Ahlstrom Corporation. Vimpu Intressenter now owns 2,358,013 shares of Ahlstrom Corporation, which represents 5.05% of the share capital and voting rights of Ahlstrom Corporation. Ahlstrom's share capital consists of 46,670,608 shares, each entitling to one vote. For more information, please contact: Liisa Nyyssönen Vice President, Communications Tel. +358 10 888 4757 Ahlstrom in brief Ahlstrom is a high performance materials company, partnering with leading businesses around the world to help them stay ahead. Our products are used in a large variety of everyday applications, such as filters, medical gowns and drapes, wallcoverings, flooring, labels and food packaging. We have a leading market position in the businesses in which we operate. Our 5,200 employees serve customers in 28 countries on six continents. In 2011, Ahlstrom's net sales amounted to EUR 1.6 billion. The company's share is quoted on the NASDAQ OMX Helsinki. More information is available at www.ahlstrom.com. This announcement is distributed by Thomson Reuters on behalf of Thomson Reuters clients. The owner of this announcement warrants that: (i) the releases contained herein are protected by copyright and other applicable laws; and (ii) they are solely responsible for the content, accuracy and originality of the information contained therein. Source: Ahlstrom Oyj via Thomson Reuters ONE [HUG#1645808]