Berkshire Hathaway decreased its stake in Apple by nearly 3 million shares, to 249.5 million, in the fourth quarter, but Warren Buffett reportedly had nothing to do with the selling.

"One of the managers other than Warren had a position in Apple and sold part of it in order to make an unrelated purchase," Buffett's assistant Debbie Bosanek said in an email to Reuters. "None of the shares under Warren's direction have ever been sold."

Bosanek didn't immediately respond to CNBC's request for comment. Berkshire didn't return CNBC's call seeking comment.

Buffett first announced Berkshire was buying Apple in February 2017 despite his usual aversion to tech stocks. And since then, Berkshire's position in the iPhone-maker has grown significantly. By the end of 2017, Buffett's conglomerate already owned 165.3 million Apple shares, and it bought another 75 million shares in the first quarter of 2018.

Buffett 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."