Zurich Financial Services is outsourcing IT services to CSC for ten and a half years.
The contract could be worth up to $2.9bn if Zurich takes up the full range of services on offer.
CSC will provide data centre centralisation and server virtualisation, which will result in a reduction in hardware and increased energy efficiency.
CSC said: "The contract is designed to transform Zurich's existing data centre environment into a fully modernised, flexible and highly virtualised operation."
The global contract allows for country specific agreements to be arranged locally and will commence when the first of these is signed. This is expected to be in the first half of 2010.
Up to 1,000 Zurich employees could be transferred to CSC depending on the nature of the local agreements entered into.
CSC has been supplying Zurich with IT services since 2004 when they agreed a $1.3bn contract.