By Thursday morning, the stock fallen about 9 percent or about $15 per share.
The drop brings Berkshire's holdings to about $36.1 billion, and a $3.76 billion loss.
In the first quarter of 2018, Buffett's Berkshire bought 75 million shares of Apple. That added to an existing 165.3 million shares Berkshire already owned at the end of 2017. He told CNBC at the time that he clearly likes Apple, and "we buy them to hold."
"We bought about 5 percent of the company. I'd love to own 100 percent of it. ... We like very much the economics of their activities. We like very much the management and the way they think," Buffett told CNBC's "Squawk Box."
Berkshire did not return a call for comment.
Buffett first announced Berkshire was buying Apple in February 2017 despite his usual aversion to tech stocks. On Feb. 1, 2017, Apple's shares were around $129 so the Oracle of Omaha is likely still in the green on the first portion of stock he bought. But Berkshire added to that stake significantly the last two years at likely higher prices.
Berkshire's other major bets aren't holding up much better.
In the financial sector Bank of America, which makes up 11 percent of Berkshire's portfolio, is down 17 percent year over year while Wells Fargo is down 24 percent. Those are the holding company's two largest positions behind Apple. J.P. Morgan meanwhile, which makes up 1.9 percent of the portfolio, is down roughly 9.5 percent in the same period.
Coca Cola, Berkshire's fourth largest position at 10 percent of the portfolio is in positive territory, up 2.5 percent over the last 12 months while American Express is down 4 percent.