NEW YORK (Reuters) — Warren Buffett’s Berkshire Hathaway Inc. and Hartford Financial Services Group Inc. are teaming up to offer commercial property insurance to customers who might not otherwise qualify for coverage, Hartford said yesterday.Hartford said the companies will offer expanded “surplus lines” coverage for what it called “difficult, unusual or high risk” accounts. It said owners can use such coverage for apartment buildings, vacant buildings, remote manufacturing plants, and properties in catastrophe-prone regions.

Hartford said the partnership is between its First State Management Group unit and three Berkshire units: National Fire & Marine Insurance Co., National Indemnity Co. and National Indemnity Co. of the South. Coverage limits might reach $25 million, and on average be twice what First State offered before, Hartford said.

Omaha, Nebraska-based Berkshire usually generates more than half its profit from insurance. Results in 2006 benefited from the company’s willingness to offer higher-risk coverage after Hurricane Katrina and other storms the previous year caused many rivals to reduce their own storm exposures.

In his February 28 letter to Berkshire shareholders, Buffett said his company remains prepared to lose $6 billion from a single storm, but has reduced exposure to wind claims because rates were falling. Berkshire was not immediately available for further comment.