Ahlstrom Corporation STOCK EXCHANGE RELEASE June 24, 2013 at 09.00

Ahlstrom's Label and Processing business in Europe (LP Europe) was transferred to Munksjö Oyj through a partial demerger, which was registered with the Finnish Trade Register on May 27, 2013. The original acquisition cost of Ahlstrom shares will be divided between Ahlstrom shares and Munksjö shares received in the demerger in Finnish income taxation. The acquisition cost is used for the calculation of capital gains and/or losses from share transactions for the basis of Finnish taxation.

Based on the average weighted trading prices, the proportion of the current values of Munksjö and Ahlstrom shares do not differ significantly from the proportion of net assets of LP Europe and the total net assets of Ahlstrom. Thus, the original acquisition cost of Ahlstrom's shares is divided based on the proportion of net assets at the effective time of the demerger. LP Europe's transferred net assets were 11.3% of the total net assets of Ahlstrom.

Ahlstrom shareholder received one Munksjö Oyj share for each four shares held in Ahlstrom prior to the completion of the LP Europe demerger. Of the original acquisition cost of one Ahlstrom share, 11.3% will be transferred to an acquisition cost of 0.25 Munksjö share.

Example: If an Ahlstrom shareholder has purchased four Ahlstrom Oyj shares at a total price of EUR 40 (EUR 10 per share), then the acquisition cost of one Munksjö share received through LP Europe demerger consideration is EUR 4.52 (11.3%* EUR 40). The acquisition cost of the four Ahlstrom shares will then be EUR 35.48 or EUR 8.87 per share.

This does not apply to Ahlstrom shareholders residing permanently outside of Finland. Shareholders who are tax resident outside of Finland are recommended to contact their tax advisors or local tax office regarding the split of the acquisition cost in taxation.

For more information, please contact:

Juho Erkheikki
Manager, Financial Communications & Investor Relations
Tel. +358 10 888 4731

Liisa Nyyssönen
Vice President, Communications
Tel. +358 10 888 4757

Ahlstrom in brief
Ahlstrom is a high performance fiber-based 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, diagnostics, wallcoverings, flooring and food packaging. We have a leading market position in the businesses in which we operate. In 2012, Ahlstrom's net sales from the continuing operations (excluding Label and Processing business) amounted to EUR 1 billion. Our 3,800 employees serve customers in 28 countries on six continents. Ahlstrom's share is quoted on the NASDAQ OMX Helsinki. More information available at www.ahlstrom.com.