SoftBank Group may propose to T-Mobile US that the American mobile carrier enter merger talks with SoftBank's U.S. subsidiary Sprint, sources said Thursday.

This comes after an earlier bid to buy T-Mobile US and merge it with Sprint — a move SoftBank abandoned in 2014 thwarted by difficulties in getting approval from U.S. regulators who had been concerned about the consolidation of mobile carriers.

T-Mobile US ranks third in the U.S. market by subscription contracts. A merger with Sprint, the fourth-largest, would create a mobile group rivaling Verizon Communications and AT&T — respectively the No. 1 and No. 2 carriers in the country.