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

Ahlstrom Corporation STOCK EXCHANGE RELEASE 21.5.2010 at 16.15

Pursuant to Chapter 2, Section 9 of the Securities Market Act, Ahlstrom Corporation has received an announcement from Mr Erkki Etola, dated May 21, 2010, regarding a change in the shareholding of said shareholder.

According to the announcement, Erkki Etola's shareholding in Ahlstrom Corporation has on May 20, 2010, exceeded 5 % (1/20) of the share capital and voting rights of Ahlstrom Corporation. Erkki Etola now owns 2,441,500 shares of Ahlstrom Corporation, which represent 5.23% 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.

 Ahlstrom Corporation
Corporate Communications

For further information, please contact:
Seppo Parvi, CFO
Tel. +358 10 888 4768

Distribution:
NASDAQ OMX Helsinki
Main media
www.ahlstrom.com

Ahlstrom in brief
Ahlstrom is a global leader in the development, manufacture and marketing of high performance nonwovens and specialty papers. Ahlstrom´s products are used in a large variety of everyday applications, such as filters, wipes, flooring, labels, and tapes. Based upon its unique fiber expertise and innovative approach, the company has a strong market position in several business areas in which it operates. Ahlstrom's 5,800 employees serve customers via sales offices and production facilities in more than 20 countries on six continents. In 2009, Ahlstrom's net sales amounted to EUR 1.6 billion. Ahlstrom's share is quoted on the NASDAQ OMX Helsinki. The company website is at www.ahlstrom.com.