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                                    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 June, 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






                           Converium Holding Ltd, Zug

Zug, Switzerland - June 15, 2004 - Converium Ltd today announced the successful
private placement of US$ 100,000,000 of floating rate notes issued by Helix 04
Limited, a Bermuda special purpose exempted company. By means of a counter party
contract with the issuer, the transaction provides Converium with fully
collateralized second and subsequent event protection for North Atlantic
hurricane, US earthquake, Japanese earthquake and European windstorm property
catastrophe exposures. The notes are triggered only by second and subsequent
events in any of the four peril regions during the five-year term of the
transaction.

Following the success of the expiring Trinom transaction, Converium made the
strategic decision to access the capital markets in order to secure capacity in
advance of a major catastrophe event. The Helix transaction's scope is broader
than Trinom's. Coverage is based on modeled losses to a notional portfolio. The
notional portfolio was structured by Converium to reflect its European
windstorm, US earthquake, Japanese earthquake and North Atlantic hurricane
exposures. Converium expects to benefit from predefined attractive fixed
pricing.

Converium was responsible for structuring, which was carried out in conjunction
with Aon Capital Markets who also underwrote the issue as sole manager and
book-runner. Risk modeling and analytical services for this transaction were
provided by AIR Worldwide Corporation using its hurricane, earthquake and
windstorm models. The notes were priced at LIBOR plus 5.40% with a maturity of 5
years. Standard & Poor's rated the notes BB+.

"This transaction once again proves Converium's ability to access the capital
markets as an alternative to traditional retro markets," said Dirk Lohmann,
Converium's Chief Executive Officer. "In sponsoring Helix 04, Converium offered
investors the opportunity to share in a well-defined structure which they can
use to diversify their portfolios. We have also secured our shareholders'
interest by reducing our exposure to price increases and credit risk following a
major industry event. In addition, we were able to benefit from favorable
conditions currently prevailing in the capital markets."



                                  * * * * * * *



The company has made it a policy not to provide any quarterly or annual earnings
guidance and it will not update any past outlook for full year earnings. It will
however provide investors with perspectives on its value drivers, its strategic
initiatives and those factors critical to understanding its business and
operating environment.


Enquiries:

Michael Schiendorfer                       Zuzana Drozd
Media Relations Manager                    Head of Investor Relations

michael.schiendorfer@converium.com         zuzana.drozd@converium.com

Phone:         +41 (0) 1 639 96 57         Phone:         +41 (0) 1 639 91 20
Fax:           +41 (0) 1 639 76 57         Fax:           +41 (0) 1 639 71 20


About Converium

Converium is an independent leading global multi-line reinsurer known for its
innovation, professionalism and service. Today Converium ranks among the top ten
professional reinsurers and employs approximately 850 people in 22 offices
around the globe. Converium is organized into three business segments: Standard
Property & Casualty Reinsurance, Specialty Lines and Life & Health Reinsurance.
Converium's net losses for the September 11, 2001 terrorist attacks in the
United States are capped at US$ 289.2 million by its former parent, Zurich
Financial Services. Converium has minimal A&E exposures. Converium has an "A"
rating (stable outlook) both from Standard & Poor's and A.M. Best Company.






                                   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:  June 15, 2004