The new venture by Buffett's Berkshire Hathaway Assurance Corp., backed by an almost-certain triple-A credit rating, reportedly plans to guarantee loans local governments use to finance sewer systems, schools, hospitals and other public projects.

The initial program covers only New York state but expansion is reported probable.

It looks to be a tough competitor and likely cheered by municipalities and municipal-bond investors when other bond insurers' ratings look wobbly, the Wall Street Journal said Friday.

Buffett said in a Journal interview that interest appears high enough for the new company to seek permission to operate in other states that account for a large chunk of municipal-debt issuance. After New York, he said, he expects to seek approval to open in California, Puerto Rico, Texas, Illinois and Florida.