Here’s the latest sign that the telecom business is headed for upheaval: Sprint’s Chairman Masayoshi Son is talking to Warren Buffett and Liberty Media’s John Malone about a deal that could funnel billions into the No. 4 wireless company, The Wall Street Journal reports.

News of the talks, taking place separately at this week’s Allen & Co. conference in Sun Valley, sent Sprint shares up more than 5% in afternoon trading.

The conversations are said to be “at an early stage.” But they could involve the sale of some of Son’s 80% stake in Sprint.

They also take place in a period — running to the end of July — when Sprint, Comcast, and Charter have agreed to negotiate exclusively on a possible collaboration involving the cable companies’ new and planned wireless phone offering.

The No. 1 and 2 cable operator might invest in Sprint as part of an agreement to also use its network to bolster their Wi-Fi focused mobile services.

Sprint was talking with T-Mobile about a possible merger before it began negotiations with Comcast and Charter.

Malone is the largest investor in Charter.

The company can’t act alone, though: It agreed with Comcast in May to “work only together with respect to national mobile network operators” for one year. They specified, in an SEC filing, that during that period they can’t make a major deal affecting their wireless businesses without each other’s “prior consent.”

Malone might be bound by that agreement. But it probably would not apply to Buffett.

A Sprint deal to help Comcast and Charter’s wireless phone services might “facilitate” antitrust approval for a merger with T-Mobile, Evercore ISI’s Vijay Jayant said this week. It would “give regulators confidence that the consumer-facing impact of a combination would be muted.”