Form 6-K

                             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 April, 2007

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

                                 Dammstrasse 19
                                   CH-6301 Zug
                    (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 - April 17, 2007 - Converium reports strong growth of 35% in
April 1 open market treaty renewals at improved profitability.

Converium  recorded a very  successful  April 1 renewal of open-market  non-life
treaties.  The Company wrote and bound non-life contracts of USD 142 million, an
increase of 35%. New and restructured business amounts to USD 52 million,  while
increases due to share or price increases resulted in a growth of USD 8 million.
Business  of USD 23  million  was not  renewed  as it did not  meet  Converium's
profitability standards.

This excellent  result reflects  Converium's  success in regaining  business and
establishing  new client  relationships  following the recent ratings upgrade by
Standard & Poor's to "A-" ("strong").  The April 1 renewals  primarily  included
business written in Asia-Pacific.  Compared with last year the  profitability of
the renewed business has slightly improved even though overall market conditions
have continued to soften.  As anticipated,  Converium has clearly benefited from
access to more attractive business as a result of the ratings upgrade.

In addition to the open-market business, Converium agreed on the pricing for the
medical  malpractice  insurance  policies of the members of the Medical  Defence
Union  (MDU)  in the UK with  whom the  Company  has a  long-standing  strategic
alliance.  Business  from this key  relationship  is  expected  to reach USD 198
million in 2007.  This brings the total of renewed  business to USD 340 million,
an increase of 25% compared with last year's April renewals.  Overall, the April
renewals  account for roughly 15% of  Converium's  business  that is expected to
reach USD 2.2 billion in 2007.

Inga  Beale,  Chief  Executive  Officer:  "I am very  pleased  with the  April 1
renewals.  The  great  results  demonstrate  that we  deliver  on our  promises:
Converium has taken a powerful first step towards  restoring its market position
and improving profitability following the ratings upgrade."

Inga  Beale  continued:  "We  believe  that  the  renewals  are  an  unequivocal
indication  of our  clients'  desire to  maintain  and rebuild  strong  business
relationships with Converium as a stand-alone  entity. We are very encouraged by
our clients' support."

Standard Property & Casualty Reinsurance:  Dynamic expansion in Asia-Pacific and
Latin America

In Asia-Pacific,  Converium wrote and bound non-life business of USD 57 million,
an increase of 15%. In the Japanese market, which accounts for two thirds of the
renewed Asia-Pacific book of business,  premium volume grew by 12%. This success
was achieved  despite a softening  pricing  environment  and a continuing  trend
towards  increasing  retentions among direct  insurers.  In India, the Company's
book  of  business  almost  doubled  through  the  establishment  of new  client
relationships in a very dynamic market  environment.  Converium's Latin American
business  also recorded  strong  growth of 21%, with USD 14 million  written and
bound.  In the Middle East,  Converium grew by 38%.  Finally,  in North America,
Converium managed to win smaller property books of business.

Kobi  Eugster,  Executive  Vice  President  for  Standard  Property  &  Casualty
Reinsurance,  comments: "These strong results clearly demonstrate how successful
we are in  restoring  and  expanding  our  position  in the  emerging  insurance
markets, one of Converium's core strategic areas."

Specialty Lines: Strong recovery following ratings upgrade and new business from
Brazilian deal

In global  Specialty Lines,  another core area for Converium,  the Company wrote
and bound business of USD 52 million, an increase of 70% compared to last year's
April  renewals.   Business   expansion  was  particularly   pronounced  in  the
agribusiness and credit & surety lines of business, with increases of 305% (from
USD 3 to 13 million)  and 212% (from 3 to 8 million),  respectively.  The strong
growth in  agribusiness  reflects  Converium's  success in further  expanding an
innovative  insurance  program in the Brazilian market targeted at local farmers
and landowners.

The  excellent  renewal  results in Standard  Property & Casualty and  Specialty
Lines are testament to the Company's  strong  franchise  which was  successfully
maintained after the downgrades in 2004 and now, as anticipated,  proves to be a
promising basis for significant profitable growth going forward.

Benjamin Gentsch, Executive Vice President for Specialty Lines and Life & Health
Reinsurance: "I am very pleased with this year's April renewals. We have taken a
first  important  step  towards  returning  Converium  to  a  leading  specialty

Reiteration of overall premium target for 2007

Following  the  results  of  the  April  renewals,   Converium   reiterates  its
expectation  of writing  gross  premiums for the 2007  calendar  year of USD 2.2
billion,  including  Life & Health  business.  The Company also  re-affirms  its
commitment  to adhere to strict  underwriting  standards in order to achieve its
core target of growing the book of business at an improved profitability.


Beat W. Werder                                  Marco Circelli
Head of Public Relations                        Head of Investor Relations             

Phone:     +41 (0) 44 639 90 22                 Phone:      +41 (0) 44 639 91 31
Fax:       +41 (0) 44 639 70 22                 Fax:        +41 (0) 44 639 71 31

Dr. Kai-Uwe Schanz Inken Ehrich
Chief Communication & Corporate Development     Investor Relations Specialist

Phone:     +41 (0) 44 639 90 35                 Phone:      +41 (0) 44 639 90 94
Fax:       +41 (0) 44 639 70 35                 Fax:        +41 (0) 44 639 70 94

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
(outlook  stable) 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 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 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 SCOR S.A. is successful in its unsolicited  tender offer, 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.


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: April 18, 2007