"We bought it in the first quarter, and normally I wouldn't tell you this, but we bought some in the third quarter," Buffett told the cable television network.

Buffett's Berkshire owned a more than 8 percent stake in IBM as of June 30. IBM shares, which have slumped nearly 12 percent so far in the third quarter through last Friday during broad stock market volatility, last traded up 1.9 percent at $146.42 in afternoon trading Tuesday.

Buffett also said that the U.S. economy was not growing at a "booming" rate but remained on the path it has been on for six years of growing at a rate of 2 percent or a little better annually. He said he would "be a little careful" about getting too excited about quarterly statistics.

Buffett made his comments after Commerce Department data in late August showed U.S. gross domestic product expanded at a 3.7 percent annual pace in the second quarter instead of the 2.3 percent rate reported the previous month.

Buffett also said Berkshire still has ample cash after agreeing to buy Precision Castparts Corp for over $32 billion and would never hold less than $20 billion in cash.

"I’ve still got money left to buy, I’ll never go below $20 billion of cash, in fact I won’t even really go very close to it," he said.

He said Berkshire "might be a little less aggressive in the open market" given the Precision Castparts deal, but added: "I haven’t held back from doing anything because of that upcoming purchase."

Buffett, whose Berkshire owns warrants entitling it to buy 700 million Bank of America shares at $7.14 each between now and 2021, said that if he could vote on Bank of America Chief Executive Brian Moynihan's title, he would vote to have him in both the CEO and chairman roles.

Buffett also said Democratic presidential candidate Bernie Sanders "has run a model campaign" and said the 2016 Republican presidential race reminded him of "being at an amusement park and watching all the kids in bumper cars."

"What you’re seeing is indicative of a lot of dissatisfaction in the country with Washington politicians and perhaps the media to some extent too."

(Reporting by Sam Forgione; editing by Franklin Paul, Andrew Hay and Bernard Orr)