CNBC's Becky Quick, in an interview from Omaha that aired Friday, asked him if Berkshire owns any IBM shares.
He said, "No."
"I think we have zero," he said.
"The answer is almost certain, yes," on Berkshire owning no more IBM shares, he said.
As of the end of 2017, Berkshire had owned more than 2 million shares of IBM, after having sold down about 94.5 percent of its once-massive stake.
Berkshire revealed in 2011 it bought $10.7 billion worth of common stock in IBM, or 64 million shares at an average price of $170 per share.
Berkshire's transition out of IBM and into Apple marks a changing of the guard of sorts in tech stocks.
Buffett revealed to CNBC late Thursday that Berkshire bought 75 million more Apple shares in the first quarter, adding to its already huge stake of 165.3 million shares.
As of Thursday's closing price of $176.89 per share, Berkshire's Apple stake was worth about $42.5 billion. Berkshire is now the third largest Apple shareholder, behind Vanguard and BlackRock.
IBM and Apple were rivals in the 1980s, but the two companies have taken different paths over the ensuing decades, with IBM struggling with trends in enterprise technology and Apple becoming a dominant force in consumer electronics.
Buffett spoke to CNBC on Thursday evening from Omaha, Nebraska, where tens of thousands of Berkshire shareholders were gathering for Saturday's annual meeting.
— CNBC's Anita Balakrishnan contributed to this report.