Berkshire Hathaway Chairman and CEO Warren Buffett.

NEW YORK (CNN/Money) - Billionaire investors Warren Buffett and George Soros are getting hooked up with cable.

Filings with the Securities and Exchange Commission show Buffett's company, Berkshire Hathaway (Research), doubled its holdings in Comcast Corp. (Research), the nation's largest cable operator to 10 million shares, during the fourth quarter, while it dumped its shares in hospital operator HCA (Research) and slashed its holdings in athletic apparel manufacturer Nike (Research).

Soros Fund Management LLC disclosed in its own SEC filing that as of Dec. 31, it owned 2.6 million shares of Time Warner (Research), owner of Time Warner Cable, the nation's No. 2 cable operator, as well as a host of other media properties, including CNN/Money. It had no shares in Time Warner at the end of the third quarter.

Soros's fund also bought 17 million shares of satellite television operator Echostar Communications (Research) during the quarter, adding another company it did not own on its earlier report. And it bought 209,272 shares of media conglomerate News Corp. (Research), which besides owning a number of broadcast and cable networks recently gained satellite television provider DirecTV.

Berkshire Hathaway also bought a stake of 375,500 shares of dairy Dean Foods (Research) during the quarter after having no stake in the company three months earlier.

The company sold all 13.5 million shares it had held at the end of the third quarter in HCA (Research), which operates nearly 200 hospitals.

The company also sold more than half its shares in Nike (Research), cutting its holdings to 2.5 million shares from 6 million three months earlier. And it trimmed its holdings in records storage and information management company Iron Mountain (Research) by 28 percent to 5 million shares.

Berkshire also made more modest changes in some of its holdings, including adding about 3 percent to its holdings in apparel retailer Gap Inc. (Research) to 15.4 million shares, and 1 percent in IT services firm Comdisco Holdings (Research). It also added just less than 1 percent to its stake in insurer Torchmark (Research).

Most of its major holdings, including 200 million shares in Coca-Cola (Research), 151.6 million shares of American Express (Research) and 96 million shares of Gillette (Research), were left unchanged during the quarter. Buffett announced in January he intended to increase his stake in Gillette due to the proposed purchase of the company by consumer products firm Procter & Gamble (Research).

Soros's fund owns shares in far more companies than are held by Berkshire Hathaway, and it had moves in more of its holdings. Among the other high profile investments it made during the quarter was adding Cisco Systems (Research) to its holdings with 2.5 million shares.

It also made investments in a number of drug companies, adding 817,000 shares of embattled drugmaker Merck & Co. (Research), to the modest holdings of 11,000 shares it held going into the quarter. It also added shares of Pfizer (Research) and Schering Plough (Research).