OMX - Major shareholder announcements

Change in holding in OMX

Stock Exchange Announcement, August 13, 2007                                    


Change in holding in OMX 
                                                       
Citigroup Global Markets Limited announced on August 10, 2007, that they have   
increased their holding in OMX AB. The total holding in OMX AB now amounts to   
7,559,302 shares, equivalent to 6.27 percent of the current 120,640,467         
outstanding shares and votes.                                                   

For further information, please contact:                                        
Jakob Håkanson, Vice President, Investor Relations, OMX    +46 8 405 60 42      







About OMX | OMX is a leading expert in the exchange industry. The common        
offering from OMX Nordic Exchange in Helsinki, Copenhagen, Stockholm,           
Iceland, Tallinn, Riga and Vilnius, comprises over 800 companies including its  
alternative market First North. OMX provides technology to over 60 exchanges,   
clearing organizations and central securities depositories in over 50 countries.
OMX is a Nordic Large Cap company in the Financials sector on the OMX Nordic    
Exchange. For more information, please visit www.omxgroup.com.

Attachments:

070813_citygroup_en.pdf