Bloomberg News is reporting that Canton-based OneBeacon Insurance Group has hired Lehman Bros. to find a buyer for its auto and home business.

The sale price may end up being more than $500 million, according to unnamed sources who spoke to Bloomberg on conditions of anonymity. Potential buyers could include European insurers looking to gain market share in the Northeast.

The company’s net written premiums from personal insurance fell 14 percent in 2007, to $690 million. Its commercial insurance business rose 1.4 percent to $728 million, and its specialty insurance unit rose 2 percent to $446 million.

The company could be looking to shed its auto and home business in order to focus on segments with more growth potential.

Carmen Duarte, a OneBeacon spokeswoman, told Banker & Tradesman earlier this month that the company was interested in focusing on its bevy of niche businesses. It has underwriting offerings for things like public entities, ships and cargo – even professional liability for entertainment agents, as of January of this year.

“[Focusing on niche businesses] fits very much into the kind of company that we are working very hard to become,” Duarte said at the time.

OneBeacon is majority-owned by Hanover, N.H.-based White Mountains Insurance Group White Mountains bought OneBeacon in 2001 and owns roughly 75 percent of the company after taking it public in 2006.

OneBeacon spokespeople declined comment.