Warren Buffett more than doubles Apple stake

Superstar investor Warren Buffett revealed Monday that he had more than doubled his stake in Apple, to own 2.5% of the tech giant — giving his Berkshire Hathaway holding company shares in Apple worth around $17 billion.

Buffett has previously claimed that he's not a tech investor, but said in an interview with CNBC that he's bullish on Apple's powerful brand and . Berkshire Hathaway now owns 133 shares in Apple, making it the second-biggest stock in its portfolio after Coca-Cola.

"Apple strikes me as having quite a sticky product, and an enormously useful product to people that use it," Buffett said in the CNBC interview.

Apple shares were up 0.3% in premarket trading Monday. The stock has hit record highs in February, after closing at $136.66 per share Friday.

See photos of Buffett through the years: