Warren Buffett buys a stake in Rupert Murdoch’s 21st Century Fox by Tom Huddleston, Jr. @FortuneMagazine February 17, 2015, 6:00 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Berkshire Hathaway, billionaire Warren Buffett’s investment vehicle, beefed up its media holdings in the fourth quarter by taking a stake in 21st Century Fox FOX . In a quarterly filing with the Securities and Exchange Commission Tuesday, Berkshire revealed that it bought 4.7 million shares of the Rupert Murdoch-run company during the fourth quarter. The company was formed as the result of the 2013 split of News Corp.’s publishing and mass media businesses and, last year, Murdoch used it to make an unsuccessful run at buying rival Time Warner TWX . Berkshire’s addition of the Fox stake follows last year’s investment in cable television provider Charter Communications CHTR . The firm first revealed its investment in Charter last summer and Tuesday’s filing showed that Berkshire increased its stake in the cable provider from nearly 5 million shares to 6.2 million during the fourth quarter. The firm also raised its stakes in satellite television company DirecTV DTV , Viacom VIA and Liberty Global LBTYA . (Liberty Global is chaired by John Malone, who also chairs Charter’s largest shareholder, Liberty Media.) The SEC filing also revealed that Berkshire took a much larger stake in Deere & Co., as Buffett’s firm increased its holdings of the agricultural and construction equipment company from 7.6 million shares to 17.1 million. Shares of Deere DE jumped by about 1% in after-hours trading on news of the Berkshire investment. Meanwhile, Berkshire completely liquidated what was a roughly $4 billion stake in energy giant Exxon Mobil XOM during the fourth quarter. Buffett’s firm unloaded about 41 million Exxon shares after initially investing in the company less than two years ago, The Wall Street Journal notes. Exxon is the largest U.S. oil company, but its stock is down more than 9% since last summer due to the huge drop-off in worldwide oil prices.