Sprint has reportedly approached Warren Buffett about an investment
Son also met with John Malone, the cable mogul, at the Allen & Co. annual conference in Sun Valley, Idaho, the report on Friday said.
The Journal reported that details of the deal are still unclear, but could be an over $10 billion investment in Sprint from Berkshire Hathaway.
Spring shares gained as much as 4% after the news crossed.
Amid fierce competition and price cuts among the largest telecoms companies, the chief financial officer of T-Mobile said the company would benefit from a merger with Sprint. Sprint's controlling shareholder was gearing up for deal talks with T-Mobile's top shareholder, Deutsche Telekom AG, Reuters reported in May.