Amazon's business is becoming more profitable by the quarter.
The stock market's very rough April saw some of the biggest gainers of the first three months take some of the biggest dings to their market caps. And at the same time, some of the sectors that struggled in Q1 saw a similar reversal of fortune in April.
Although Berkshire Hathaway's $372 billion portfolio contains 45 stocks, three are a clear step above the rest in May.