OMB APPROVAL OMB Number: 3235-0116 Expires: March 31, 2003 Estimated average burden hours per response: 8 Form 6-K SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Report of Foreign Private Issuer Pursuant to Rule 13a-16 or 15d-16 of the Securities Exchange Act of 1934 For the month of October, 2004 CONVERIUM HOLDING AG ------------------------------------------ (Translation of registrant's name into English) Baarerstrasse 8 CH-6300 Zug Switzerland ------------------------------------------------------- (Address of principal executive offices) Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F. Form 20-F X Form 40-F ------- ------- Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934. Yes No X ------- ------- If "Yes" is marked, indicate the file number assigned to the registrant in connection with Rule 12g3-2(b): 82- Not Applicable 990231.3 Odey Asset Management LLP acquires 5.84% in Converium registered shares (held and managed in various funds) Converium Holding Ltd, Zug, has been notified pursuant to Art. 20 of the Swiss Stock Exchange Act that Odey Asset Management LLP, 12 Upper Grosvenor Street, London W1K 2ND, United Kingdom, has acquired 8,559,920 registered shares with voting rights. This corresponds to 5.84% of Converium's registered share capital. These shares are held and managed in various funds. None of these funds is holding shares in an amount, which exceeds 5% of Converium registered share capital. Odey Asset Management LLP is a UK FSA registered fund management house, and acts as the investment manager for several funds. Zug, October 21, 2004 Contacts: Zuzana Drozd Head of Investor Relations zuzana.drozd@converium.com Phone +41 (0) 1 639 91 20 Fax +41 (0) 1 639 71 20 Michael Schiendorfer Media Relations Manager michael.Schiendorfer@converium.com Phone +41 (0) 1 639 96 57 Fax +41 (0) 1 639 76 57 www.converium.com SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. CONVERIUM HOLDING AG By: /s/ Dirk Lohmann Name: Dirk Lohmann Title: CEO By: /s/ Christian Felderer Name: Christian Felderer Title: General Legal Counsel Date: October 22, 2004