SoftBank Group Corp. named Marcelo Claure chief operating officer, elevating Sprint Corp.’s top executive into a broader role after he negotiated a merger between the U.S. wireless operator and T-Mobile U.S. Inc.

As part of the transition, Claure, 47, will become executive chairman at Sprint and cede the CEO post to Michel Combes, currently the chief financial officer. In his new roles, Claure will continue to work on the Sprint/T-Mobile combination, which still faces a challenging regulatory review in Washington before it can close.

At SoftBank, Claure will become COO under founder Masayoshi Son and focus on improving execution in and among the company’s portfolio of businesses. SoftBank has used cash from its Japanese operations to buy stake in companies such as Sprint, Yahoo Japan Corp. and Alibaba Group Holding Ltd. It also set up the largest-ever technology investment fund and made investments in startups from ride-hailing pioneers Uber Technologies Inc. and Didi Chuxing to Indian e-commerce leader Flipkart Online Services Pvt. and satellite provider OneWeb.

“Masa will make the investments then I will focus on helping these companies execute effectively,” said Claure in a telephone interview.

He said his first priority will be working to complete the T-Mobile deal by persuading U.S. regulators to grant approval. Then with his background as entrepreneur and operator, he’ll work with SoftBank-backed companies on strategy and operations. He also wants to take more advantage of collaboration between the portfolio companies.

“Startup companies always want to come someplace where there is more than just money,” he said.

SoftBank did not designate Claure as heir apparent to Son. Nikesh Arora, who held the role of COO between 2015 and 2016, was supposed to be on track to take over as CEO, but left when Son decided he wanted to remain at the helm for another five to 10 more years.

Claure, who spent most of his childhood in Bolivia, started his business career early, selling clothes outside his mother’s house when he was 10. While studying at Bentley University in Waltham, Massachusetts, he made money buying and selling frequent-flier miles.

He founded a mobile-phone distributor called Brightstar Corp. in 1997, while still in his twenties, and built the Miami-based company into a logistics provider for carriers, retailers and corporate customers. SoftBank bought a majority stake in Brightstar in 2013 for $1.26 billion, then purchased the rest of the company the next year as Son tapped Claure to take over the Sprint CEO role.

Sprint has struggled against the U.S. wireless leaders. The Overland Park, Kansas-based company has lost money every year since and was surpassed as the No. 3 wireless operator by T-Mobile in 2015. The top two players are Verizon Communications Inc. and AT&T Inc.

Claure and SoftBank argue Sprint has made substantial improvements in recent years. It’s gone from losing more than 1 million customers in fiscal 2013 to adding them. It also posted a net profit in the most recent quarter, while analysts had predicted a loss.

“The business has turned around and stabilized,” said Claure.

Son had tried for years to combine the two smaller U.S. wireless operators. They pulled the plug on one merger attempt in 2014 after meeting resistance from regulators in Washington. Last year, negotiations broke down over how to structure control over the combined entity.

Claure and his counterpart at T-Mobile, John Legere, sniped at each other for years over social media. But behind the scenes, the two CEOs began putting together a revived agreement this year. That culminated in the preliminary agreement for T-Mobile to acquire Sprint for $26.5 billion. If the deal is finalized, Legere will become CEO of the combined entity.

Son has often extolled the benefits of a conglomerate backing many different businesses. Now Claure will take on the task of making those supposed benefits a reality.

He said SoftBank’s portfolio companies could share best practices, for example in ride-hailing, where the company holds stake in four different startups. The chips from ARM Holdings could help monitor the safety of Uber drivers or the work patterns of customers at WeWork Cos., another SoftBank investment. He conceded that such benefits are simpler to image than realize.

“Synergies are the easiest to identify but the hardest to execute,” he said.

Already a billionaire from selling the Brightstar business, Claure is poised to collect about $78 million if shareholders and regulators approve the transaction. He’s eligible for cash severance of about $11.6 million and $54,000 of other benefits, and a long-term award of 10 million Sprint shares, worth $66.2 million at the offer price, according to compiled data.

It wouldn’t be his only big victory this year. A lifelong soccer fan, Claure teamed up with David Beckham on a years-long effort to get a Major League Soccer team in Miami. In January, they finally succeeded.