Ray Barrette has retired as chief executive of White Mountains Insurance, a Bermuda financial services and insurance group, the company said on Monday.

Mr. Barrette is being replaced by head of the group?s reinsurance units, Steven Fass, effective immediately.

Mr. Barrette made a personal decision to retire and had not been asked to leave, White Mountains said in a statement. He is also to step down from the board effective immediately. Mr. Barrette will however continue as lead director of Montpelier Re Holdings Ltd., a Bermuda reinsurer that White Mountains helped to form in 2001. White Mountains continues to hold around ten percent of Montpelier?s outstanding shares, as of June 30.

In a regulatory filing with the US Securities and Exchange Commission, White Mountains said its board of directors on Friday elected Mr. Fass, 59, to take over as chief executive.

White Mountains founder Jack Byrne, who continues to sit on the board, said, in a statement, he ?would personally see to it that he (Mr. Fass) has all the resources he needs ? including me ? to continue to move White Mountains forward.?

A spokesman with a public relations firm hired by White Mountains said Mr. Fass was not giving interviews. White Mountains redomiciled to Bermuda from the US in 1999. Its principal executive office is in Hanover, New Hampshire.

It is not known whether Mr. Fass will be based in Bermuda, or New Hampshire. ?In terms of his physical location, he will be where he needs to be,? the spokesman said.

White Mountains said no employment agreement had been reached with Mr. Fass, and no contract was binding on Mr. Barrette. In its regulatory filing, the company said Mr. Fass? compensation package would be reviewed at the next board meeting. Mr. Fass is already a White Mountains director, and has worked for White Mountains? in its reinsurance operations for nearly a decade. In total, he has worked in the insurance industry for 35 years, joining White Mountains at the time it acquired one of its reinsurance unit, Folksamerica Re. Mr. Fass will continue as chief executive of White Mountain Re until a successor is identified, the company said.