Warren Buffett: Tax law delivered $29 billion to Berkshire Hathaway

...Berkshire’s $29 billion bonus stems from unrealized gains on equity investments getting taxed at a rate of 21 percent instead of the previous 35 percent rate. The gain helped push Berkshire’s net earnings in 2017 up to $44.94 billion, nearly double the $24.07 billion recorded a year earlier. 

Buffet said while the gain is “real,” it “did not come from anything we accomplished at Berkshire.”