They don't. Buffet is evidently unaware of this.
Buffet seems to be unaware of a lot of things. Surprisingly his personal finances and company structure.
With the debate on repealing the tax on dividends Buffet complained that if the tax on dividends were repealed he would pay far less in taxes on his BH income than he does now. An enterprising reporter decided to investigage.
There was a big problem with Buffet's claim. BH doesn't pay dividends!