It was not immediately clear how much of the investment was new, or how much would come directly from SoftBank itself. Son told The Wall Street Journal in an interview that the money would come from a $100 billion joint investment fund announced in October by SoftBank and the Saudi Arabian government to invest in the global technology sector.
SoftBank has said it would provide at least $25 billion for the fund in the next five years, while Saudi Arabia's public investment fund pledged to invest up to $45 billion in the same time period. The additional $30 billion would come from outside investors. During a trip to India last week, Son said he was close to securing the remaining funds.
Although Trump claimed credit for the investment, Roger Entner, an analyst at Recon Analytics, argued that much of the $50 billion may have already been destined for U.S. technology companies.
"I think it’s making hay out of something that was there already," said Entner. "In all likelihood, this comes out of the $100 billion fund. Considering the extremely large part that the U.S. has in the high-tech economy, [Son] would have probably invested something in the neighborhood anyway."
Son told reporters at Trump Tower that the funds would be invested into American start-ups. As he spoke, Son brandished a piece of paper with the same figures that Trump had announced. The paper appeared to specify that the investment would be made in the next four years.
The paper also contained the logo of Foxconn, a major supplier for Apple’s iPhones. It was not immediately clear what role Foxconn would play in the deal, but analysts speculated the company could be responsible for the additional $7 billion in investment and 50,000 new jobs listed on the paper. Foxconn could not be reached for comment.
"Seven billion [U.S. dollars] could mean that they’re going to build a factory or multiple factories in the U.S. to assemble phones. We don’t know that, but that would be the speculation," says Entner.
Trump also tweeted the news Tuesday afternoon.
Softbank owns roughly 80 percent of telecom company Sprint. Following the announcement, shares of Sprint Corp surged nearly 4 percent as of mid-afternoon.
The announcement also raised suppositions that Son might be seeking to curry favor for his U.S. business interests. Sprint and SoftBank abandoned an effort to purchase rival telecom carrier T-Mobile in 2014 after U.S. regulators signaled the deal might violate anti-trust laws. But in August, Bloomberg quoted people familiar with his thinking as saying that Son still held out hope for the merger.
A Trump administration could consider a potential merger between Sprint and T-Mobile differently, analysts said. Speaking from the lobby of the Trump tower, Son said that he wanted to celebrate Trump’s election “because he would do a lot of deregulation.”
Jeff Kagan, an Atlanta-based telecom industry analyst, said Son could be courting Trump to improve the chances of the merger, but he also described Son as an ambitious entrepreneur who was likely looking for further opportunities.
"Maybe he sees there’s a different possibility for a Sprint and T-Mobile partnership. But that’s only one slice of the pie. I don’t think Masayoshi Son is that small of a thinker," said Kagan. "He sees opportunities, based on what we’ve all seen happen in the last few weeks. And he wants to be a player."
A self-made billionaire, Son has earned a reputation as somewhat of a maverick. Since founding SoftBank in 1981, he has built the company into a telecom, internet and financial leviathan with purchases including an early investment in Chinese e-commerce giant Alibaba and the acquisition of the Japanese unit of British mobile phone company Vodafone. SoftBank also led a $1 billion investment round in online lender Social Finance Inc last year.
In November, a meeting between Trump, his daughter Ivanka and the Japanese prime minister Shinzo Abe raised controversy over potential conflicts of interest between a Trump presidency and his businesses. Ivanka has been appointed to take charge of Trump’s businesses during his time in office, which include a chain of international hotels.