Warren Buffett's Berkshire Hathaway Inc (BRKb.N) and John Malone's Liberty Media Corp (QVCA.O) are exploring an investment of between US$10 billion and US$20 billion in U.S. wireless carrier Sprint Corp (S.N), people familiar with the matter said.

Masayoshi Son, the chief executive of Japan's SoftBank Group Corp (SFTBY.PK), which controls Sprint, met Buffett and Malone separately this week at an annual gathering of CEOs in Sun Valley, Idaho, the sources said on Friday, confirming an earlier report in the Wall Street Journal.

Shares of Sprint were up five per cent at US$8.62 in afternoon trading on Friday.

Sources said last month that Sprint has entered into a two-month period of exclusive negotiations with Malone's Charter Communications Inc and Comcast Corp that has put its merger talks with U.S. wireless peer T-Mobile US Inc on hold till the end of July.

Unlike Malone, Comcast CEO Brian Roberts has shown little interest in his company investing in Sprint, the sources said.

Malone in January raised the possibility that major cable companies could get together and buy a wireless carrier.

Sprint, Berkshire Hathaway and Liberty Media did not immediately respond to Reuters requests for comment.