All big bond insurers are putting their cases to Berkshire Hathaway while their finances are scrutinized by ratings firms and investors, the newspaper said, citing unidentified people familiar with the matter.
In the process, Buffett is gaining insight into their businesses, the Journal said.
Bond insurers, which guarantee interest and capital payments on bonds in the event of default, are the latest victims of the subprime crisis; Ambac shares have fallen 58 percent since the end of September and MBIA is down 42 percent, the newspaper said.
Berkshire Hathaway, the world's only triple-A-rated reinsurer, has for a long time been willing to provide insurance against risks that no one else will contemplate, the Journal said.
While the company is unlikely to acquire a bond insurer outright, it might set up a financial guarantor that takes advantage of high prices and withdraws when prices become unfavorable, the newspaper added.