Disclosure Notice

Disclosure Notice Stockholm, October 6, 2003 Due to Pyrosequencing's acquisition of Personal Chemistry, Investor's shareholding in the new merged company, through the wholly owned subsidiary Investor Growth Capital, will amount to 6,745,734 shares corresponding to 11.7 percent of the votes and capital. Prior to the merger, Investor Growth Capital's stake in Personal Chemistry amounted to 17.0 percent of the votes and capital. An additional 929,000 shares in Pyrosequencing have been purchased on the market. In addition to the above-mentioned shares, Investor Growth Capital owns 2,438,601 warrants to buy shares in Pyrosequencing. If these warrants and warrants held by others are fully utilized, Investor Growth Capital's holding in the company will amount to 12.7 percent of the votes and capital in Pyrosequencing. INVESTOR AB For further information contact: Mikael Horal, Managing Director, Investor Growth Capital; +46 8 614 1814, +46 708 24 2014. Fredrik Lindgren, Vice President, Corporate Communications, Investor AB: +46 8 614 2031, +46 70 624 2031. Our press releases can be accessed at www.investorab.com on the Internet. Investor AB is the largest listed industrial holding company in the Nordic region. The company's business concept is to create shareholder value through long-term committed ownership and professional investment activities. Investor is a leading shareholder in a number of multinational companies, including AstraZeneca, Ericsson, and SEB. Investor also conducts private equity activities in North America, Europe and Asia. ------------------------------------------------------------ This information was brought to you by Waymaker http://www.waymaker.net The following files are available for download: http://www.waymaker.net/bitonline/2003/10/06/20031006BIT00620/wkr0001.doc http://www.waymaker.net/bitonline/2003/10/06/20031006BIT00620/wkr0002.pdf

About Us

Investor is the leading owner of Nordic-based international companies, founded by the Wallenberg family a hundred years ago. We own significant minority or majority interests in high quality companies. Through our participation on the boards of directors, we work for continuous improvement of the performance of the companies. With our industrial experience, network and financial strength we strive to make our companies best-in-class. Our cash flow allows us to support strategic initiatives in our companies, capture investment opportunities and provide our shareholders with a dividend. Our Core Investments include listed holdings Atlas Copco, SEB, ABB, Ericsson and the operating subsidiary Mölnlycke Health Care.