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 March, 2007

                              CONVERIUM HOLDING AG
                 (Translation of registrant's name into English)

                                 Dammstrasse 19
                                   CH-6301 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



News release
Converium Holding Ltd, Zug

Zug, Switzerland - March 1, 2007 - Converium upgraded to "A-" by Standard &
Poor's.

Converium announces that Standard & Poor's has raised the Company's long-term
financial strength rating to "A-" ("strong") with a stable outlook. According to
Standard & Poor's the ratings decision reflects the Group's strengthened
management team and sound infrastructure, strong competitive position, and
strong capitalization.

Markus Dennler, Chairman of Converium's Board of Directors, commented: "The
restoration of our A-rating marks the full completion of Converium's turnaround.
We thank our shareholders, clients and employees for their support and loyalty
throughout challenging times in which Converium was able to demonstrate a
uniquely strong and intact client franchise." Inga Beale, CEO of Converium,
added: "Based on our strong 2006 financial results and our robust franchise, we
are now well positioned to capture growth opportunities arising from the upgrade
throughout 2007, whilst strictly maintaining our focus on underwriting
discipline. Converium has seen a strong support from existing clients during the
important January 1, 2007 renewals. We will do everything to ensure that our
clients' trust will continue to be rewarded."

Enquiries

Beat W. Werder                             Marco Circelli
Head of Public Relations                   Head of Investor Relations
beat.werder@converium.com                  marco.circelli@converium.com
Phone:     +41 44 639 90 22                Phone:      +41 44 639 91 31
Fax:       +41 44 639 70 22                Fax:        +41 44 639 71 31


Dr. Kai-Uwe Schanz                         Inken Ehrich
Chief Communication & Corporate            Investor Relations Specialist
Development Officer                        inken.ehrich@converium.com
kai-uwe.schanz@converium.com               Phone:      +41 44 639 90 94
Phone:     +41 44 639 90 35                Fax:        +41 44 639 70 94
Fax:       +41 44 639 70 35

About Converium

Converium is an independent international multi-line reinsurer known for its
innovation, professionalism and service. Today Converium employs about 500
people in 15 offices around the globe and is organized into three business
segments: Standard Property & Casualty Reinsurance, Specialty Lines and Life &
Health Reinsurance. Converium has an "A-" ("strong") financial strength rating
with a stable outlook from Standard & Poor's and a "B++" financial strength
rating (outlook positive) from A.M. Best Company.



Important Disclaimers

This document contains forward-looking statements as defined in the U.S. Private
Securities Litigation Reform Act of 1995. It contains forward-looking statements
and information relating to the Company's financial condition, results of
operations, business, strategy and plans, based on currently available
information. These statements are often, but not always, made through the use of
words or phrases such as `seek to', `expects', `aims' `should continue',
`believes', `anticipates', `estimates' and `intends'. The specific
forward-looking statements cover, among other matters, our combined ratio,
return on equity and premium volume and expense reduction targets, our plans to
use capital more efficiently and to return capital to shareholders, the
reinsurance market, the Company's operating results, the Company's dividend
policy, our ability to obtain an upgrade of our financial strength rating and
the consequences of such an upgrade, the prospects for improving our results,
investment yield and market share. Such statements are inherently subject to
certain risks and uncertainties. Actual future results and trends could differ
materially from those set forth in such statements due to various factors. Such
factors include whether we are able to secure an upgrade of our financial
strength ratings; our ability to refinance our outstanding indebtedness and
increase our use of hybrid capital; uncertainties of assumptions used in our
reserving process; risk associated with implementing our business strategies and
our capital improvement measures; cyclicality of the reinsurance industry; the
occurrence of natural and man-made catastrophic events with a frequency or
severity exceeding our estimates; acts of terrorism and acts of war; changes in
economic conditions, including interest and currency rate conditions that could
affect our investment portfolio; actions of competitors, including industry
consolidation and development of competing financial products; a decrease in the
level of demand for our reinsurance or increased competition in our industries
or markets; our ability to expand into emerging markets; our ability to enter
into strategic investment partnerships; a loss of our key employees or executive
officers without suitable replacements being recruited within a suitable period
of time; our ability to address material weaknesses we have identified in our
internal control environment; political risks in the countries in which we
operate or in which we reinsure risks; the passage of additional legislation or
the promulgation of new regulation in a jurisdiction in which we or our clients
operate or where our subsidiaries are organized; the effect on us and the
insurance industry as a result of the investigations being carried out by the US
Securities and Exchange Commission, New York's Attorney General and other
governmental authorities; our ability to regain past customers following any
rating upgrades and the resolution of the investigations being carried out by
the US Securities and Exchange Commission, New York's Attorney General and other
governmental authorities; changes in our investment results due to the changed
composition of our invested assets or changes in our investment policy; failure
of our retrocessional reinsurers to honor their obligations or changes in the
credit worthiness of our reinsurers; our failure to prevail in any current or
future arbitration or litigation; and extraordinary events affecting our
clients, such as bankruptcies and liquidations, and other risks and
uncertainties, including those detailed in the Company's filings with the U.S.
Securities and Exchange Commission (including, but not limited to, our Annual
Report on Form 20-F filed with the U.S. Securities and Exchange Commission) and
the SWX Swiss Exchange. The Company does not assume any obligation to update any
forward-looking statements, whether as a result of new information, future
events or otherwise.

Additional information and where to find it:
In connection with the offer by SCOR, Converium expects to file a
solicitation/recommendation statement with the Securities and Exchange
Commission (the "SEC"). Investors and security holders are strongly advised to
read these documents when they become available because they will contain
important information about the tender offer and the proposed merger. Copies of
the solicitation/recommendation statement will be available free of charge at
the SEC's web site at www.sec.gov, or at Converium's website at
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/ Inga Beale
                                                    Name:      Inga Beale
                                                    Title:     CEO




                                               By:  /s/ Christian Felderer
                                                    Name: Christian Felderer
                                                    Title: General Legal Counsel



Date: March 3, 2007