The Treasury Department has begun examining whether Warren Buffett's Berkshire Hathaway is systemically important to the U.S. financial system, Bloomberg reports.
The designation, which Treasury has already given to AIG, GE, and Prudential, means Berkshire would come under Federal Reserve regulation.
Under Dodd-Frank, Treasury can decide that the scale and nature of these nonbank financial companies could pose a threat to U.S. financial stability if they became distressed.
Berkshire's class-A shares have a market cap of $285 billion, and the firm is the fourth-largest reinsurer in the world.
Bloomberg says any decision would be months away.