Stock Exchange Announcement, February 22, 2008 Change in holding in OMX Citigroup Global Markets Limited (Citigroup) announced today that they have decreased their holding in OMX AB below five (5) percent on February 20, 2008. The holding in OMX AB was decreased with 8,385,900 shares. Thereafter, Citigroup's holding in OMX AB is now 63,701 shares which represents 0.05 percent of the shares and votes of OMX AB. The share capital of OMX AB consists of 120,640,467 shares. For further information, please contact: Jakob Håkanson, Vice President, Investor Relations, OMX +46 8 405 60 42