T-Mobile US Inc. and Sprint Corp. are making progress in their merger negotiations, aiming to complete the deal talks as early as next week, according to Reuters, citing people familiar with the deal discussions. Deutsche Telekom -- T-Mobile's majority shareholder -- and SoftBank Group Corp. which controls Sprint, are working on an agreement on how they will split voting control over a joint company, according to the sources. There's still, however, no guarantee that a deal will reached, the sources said. The tie-up between the two major U.S. wireless carriers could create a company with more than 127 million customers, according to Reuters, ramping up pressure on the two biggest wireless players Verizon Communications Inc. and AT&T Inc. S merger between T-Mobile and Sprint came close to being sealed in November, but SoftBank ended the talks in the last minute.