When big financial companies have needed a rescue over the years, one man has often stood at the ready: Warren E. Buffett.

Mr. Buffett, the billionaire investor and chief executive of Berkshire Hathaway, has proved time and again that he is willing to help — for a price.

The latest company to turn to Mr. Buffett, following the likes of Goldman Sachs, Bank of America and General Electric, is the Home Capital Group, a Canadian mortgage lender that spent the last month shoring itself up after depositors abandoned it in droves after accusations of fraud.

Late on Wednesday, Home Capital disclosed that it had sold a 38 percent stake in itself to an insurance unit of Mr. Buffett’s Berkshire Hathaway, at a deeply discounted price of 400 million Canadian dollars, or about $300 million. Moreover, it accepted a 2 billion Canadian dollar loan from Mr. Buffett’s group, carrying a 9 percent interest rate, to replace an existing and slightly more expensive credit line.