CHARLOTTE (Bloomberg) ? Fidelity National Financial Inc., the biggest US title insurer, agreed to buy Sedgwick CMS Holdings Inc. for $635 million to offer third-party claims management services to Fortune 500 companies.

Marsh & McLennan Cos., the world?s largest insurance broker, and Trident II L.P., one of the buyout funds it used to manage, are the principal selling shareholders, Sedgwick said in a statement yesterday.

The acquisition would help smooth out Fidelity National?s profit by giving it access to Sedgwick CMS?s risk-management programmes, including high-frequency claims for workers? compensation and disability. The US market for third-party insurance claims processing at Fortune 500 companies is $2.5 billion, Fidelity National said.

?The long-term nature of the customer contracts and the strength of the customer relationships are very appealing and will provide growing, predictable and consistent revenue and earnings for our shareholders,? Fidelity National chairman and chief executive officer William P. Foley said in a statement.

Sedgwick is expected to have about $400 million in revenue in 2005, Jacksonville, Florida-based Fidelity National said. The purchase, funded by cash and existing credit lines, is expected to be completed January 31.

Memphis, Tennessee-based Sedgwick employs 4,000 in more than 80 offices in the US and Canada, according to its website.

Marsh sold its buyout unit to the division?s managers in May as part of a plan to restore client trust in the broker.