US billionaire Warren Buffett said Monday his Berkshire Hathaway investment firm has bought $10.7 billion worth of shares in information technology giant IBM since March.

Buffett told business television network CNBC that his investment amounts to about 64 million shares, the equivalent of a 5.5 percent stake,

The investment would make Berkshire Hathaway IBM's largest or second-largest shareholder -- investment advisory group State Street holds more than 64 million shares.

Known as the "Sage of Omaha" for his investing skills, the 81-year-old Buffett told CNBC that Berkshire had paid an average price of $170 a share, 10 percent lower than last Friday's closing price of $187.38.

The shares were up 1.3 percent in opening trade Monday; Berkshire's most widely traded "B" shares fell 0.3 percent.

Buffett said in the TV interview that Berkshire had finished its IBM spree and that he did not intend to buy more of the company.

"I wouldn't be talking about it if I did."

Buffett praised IBM, which celebrated its 100th anniversary in June, for having a strong plan for the future, saying: "They've done all kinds of things right."

In late October IBM named Virginia Rometty, the current head of sales, marketing and strategy, to take over as chief executive on January 1, making her the first woman to lead the iconic US firm.

Buffett's stock-picking prowess has made him the world's third-richest man, with a fortune of $50 billion, according to Forbes magazine's latest list of the world's billionaires.

Buffett also said Berkshire had increased its holdings in a leading US bank, Wells Fargo, but did not give any figures.