Opcon publishes an addition to its offer document

This press release may not, directly or indirectly, be distributed or published in the United States, Australia, Japan, Canada, Switzerland or South Africa. The offer is not directed to such persons whose participation is conditional upon the performance of prospectus, registration or other procedures in addition to those prescribed in Swedish law.

On 10 February 2010 Opcon submitted a public acquisition offer to shareholders of Tricorona. The offer was one (1) newly issued Opcon share for 6.5 Tricorona shares. On 18 March 2010 Opcon published the offer document regarding this offer. On 24 March a first addition to the offer document was published. A second addition to the offer document is now available at www.opcon.se. This addition has been made following the press release published by Opcon on 30 March 2010 concerning Opcon’s comment on statements from the board of Tricorona and the press release that Tricorona published on 29 March with its recommendation to the shareholders of Tricorona regarding Opcon’s offer. For further information please contact: Niklas Johansson, vice president, Investor Relations, tel. 08-466 45 00, 070-592 54 53 Opcon AB, Box 15085, 104 65 Stockholm Tel. 08-466 45 00, fax 08-716 76 61 e-post: info@Opcon.se www.Opcon.se