“The company is in terrific shape. We finished 2006 on a strong note,” he said.

Mr. Barrette originally joined the company in 1973 and was formerly CEO and a director of the company until his retirement in October 2005.

He left retirement and returned as a director in August 2006 just days after the company announced reduced second-quarter earnings.

The earnings were marred mainly by a decision to reimburse more than $130 million to investors in White Mountains' reinsurance sidecar, Olympus, when offshore energy losses from Hurricane Katrina emerged unexpectedly.

At the time, Mr. Byrne referred to the Olympus situation as a “sorry chapter” in the life of the company.

Both Mr. Byrne and Mr. Fass were investors in Olympus when it was first set up in 2001. Original investors saw their investments wiped out by a first wave of storm losses in 2005, but a new set of investors came in to recapitalize the venture prior to the emergence of the energy losses.

Referring to today's announcement, Mr. Barrette said: “I am excited about rejoining a strong management team and assuming leadership of the board. I appreciate the board's confidence and support. I will strive to always deserve both.” He thanked Mr. Byrne for 22 years of service.

“Some tactics may change,” Mr. Barrette added, “but we remain focused on our mission of delivering superior returns to our owners.”

In today's announcement, White Mountains disclosed details of stock option grants that the company said will serve as a material inducement to Mr. Barrette to accept his new positions, adding that these had been approved by the compensation committee and the board.

According to the firm's Web site, Mr. Barrette is also currently a director of Bermuda-based Montpelier Re Holdings, Ltd. In addition to prior positions at White Mountains and its subsidiaries, Mr. Barrette has been a consultant with Tillinghast-Towers Perrin and president of the personal insurance division at Fireman's Fund Insurance Company.