Supplement to prospectus dated December 15, 2004 – Publication of financial statements for 2004 for OMX and CSE

OMX and Copenhagen Stock Exchange have earlier today published their respective financial state-ments for 2004. OMX’s press release has the following wording: “2004 – Many important steps toward an integrated Nordic Baltic marketplace • Revenue amounted to SEK 3,115 m (2,686), including a gain of SEK 92 m from the sale of NGX, SEK 16 m from the sale of XACT Fonder and SEK 101 m from the divestment of APK. • Total expenses declined to SEK 2,599 m (3,256), including SEK 130 m in provisions for prem-ises and SEK 99 m in VAT repayments. • Operating income rose to SEK 524 m (loss: 449) • Adjusted operating income increased to SEK 544 m (113) • Income after financial items rose to SEK 462 m (loss: 472), including SEK 12 m in accrued interest expenses pertaining to repayment of VAT • Income after tax increased to SEK 276 m (loss: 431) • Earnings per share increased to SEK 2.39 (loss: 4.33) • The Board proposes a dividend of SEK (0) (0) per share • Merger of APK and VPC – NCSD formed • Common trading platform in entire Nordic region • Proposed merger with the Copenhagen Stock Exchange Fourth quarter 2004 • Revenues amounted to SEK 796 m (750), including SEK 101 m in gain from divestment of APK • Operating loss was SEK 17 m (income: 19) • Adjusted operating income was SEK 111 m (57) • Loss after financial items amounted to SEK 40 m (income: 10) • Loss after tax was SEK 45 m (income: 10) • Earnings per share was a loss of SEK 0.39 (income: 0.08) Enclosed you will find OMX’s Financial Statement for year-end 2004. The report is also available at www.omxgroup.com. A press and analyst briefing will be held today at 11.00 CET at OMX’s head office at Tull-vaktsvägen 15, Stockholm. For those unable to attend, it will be possible to listen in via conference call at the following numbers, UK: +44 (0) 20 7162 0181, US: +1 334 323 6203, Sweden: +46 8 505 201 14.” Please be aware that OMX’s offer to the shareholders of Copenhagen Stock Exchange expires on February 7, 2005. The completion of the offer is subject to certain conditions, including a minimum acceptance level of 90 percent. Shareholders wishing to tender their shares in Copenhagen Stock Exchange subject to the terms and conditions of the offer must contact their own account holding institution or stock brokerage company in this respect with a request for the acceptance of the offer to be communicated to Danske Bank A/S, Corporate Actions, Holmens Kanal 2-12, 1092 Copenha-gen K, Denmark, phone: +45 43 39 49 69 before the expiry of the offer period. OMX’s financial statement for year-end 2004 is available on www.omxgroup.com, and Copenhagen Stock Exchange’s annual report for 2004 is available on www.cse.dk. This prospectus supplement is available on both www.omxgroup.com and www.cse.dk. The prospectus supplement, the financial statement for year-end 2004 of OMX and the press release regarding the publication of Copenhagen Stock Exchange’s annual report for 2004 will be send to all parties having received a copy of the prospectus. For more information, please contact: Anna Rasin, VP Marketing & Communications +46 8 405 66 12