Warren Buffett bit deep into Apple in the fourth quarter.

The billionaire investor behind Berkshire Hathaway more than tripled the number of shares he owns of Cupertino, Calif., company, to 54.7 million shares, according to regulatory filings on Tuesday.

Shares of Apple have climbed 16.6 percent this year — putting Buffett’s stake in the tech giant at $7.75 billion, at least.

In an interview with talk-show host Charlie Rose last month, Buffett said he has bought $12 billion worth of stock since the election.

Buffett also increased his purchases in airline stocks during the fourth quarter.

In September, Buffett shocked the investing world after disclosing he bought $1.2 billion in airline stocks. He had long been down on the sector.

Investment managers are required to disclose in regulatory filings their long positions 45 days after the close of a quarter. Other SEC filings revealed: