Expand NASDAQ : AAPL Apple Today's Change ( -1.53 %) $ -4.80 Current Price $ 308.26 Key Data Points Market Cap $4.6T Market cap calculated using publicly traded shares outstanding only. It means Apple keeps working for Berkshire in the background, compounding its stake without any action at all. Expand NYSE : BRKB Berkshire Hathaway Today's Change ( 1.46 %) $ 7.62 Current Price $ 529.42 Key Data Points Market Cap $1.1T Market cap calculated using publicly traded shares outstanding only. Apple stock also trades at a premium, and the fact that even Berkshire took profits is a reminder that valuation matters. A stumble at Apple would still ripple straight through Berkshire's results, given how large the stake remains.