New York CNN Business  — 

In the second half of 2017, Uber was in a state of disarray. Travis Kalanick, the hard-charging cofounder and CEO who built Uber into a global force, stepped down after months of crises. The startup was hobbled by boardroom battles and a virtually empty C-Suite. And its chief US rival, Lyft, was raising more money and expanding its footprint across North America.

Against that backdrop, SoftBank CEO Masayoshi Son struck a deal to invest billions in Uber at a steep discount. Now, that decision could pay off in a big way for Son and further his ambitious bid to reshape the technology and venture capital landscapes.

Uber is expected to pull off the biggest IPO of the year this week, with a fully diluted valuation that could top $90 billion. And SoftBank (SFBTF), a Japanese conglomerate, owns 16.3% of Uber, making it the single largest stakeholder, according to the company’s IPO prospectus. SoftBank (SFBTF) acquired most of that stake by buying shares from existing shareholders at a $48 billion valuation – in what was essentially a mini-IPO – down from the $70 billion it had most recently been valued at on the private market.

On Thursday, SoftBank said the value of its stake in Uber had increased by $3.8 billion, a significant gain in a remarkably short period of time. But that amount will change depending on how Uber’s stock performs after it goes public, as SoftBank expects to hold onto most of its stake after the IPO.

For SoftBank, and its eccentric billionaire CEO, there’s more at stake than a quick return. SoftBank is in the process of shifting from the telecom business to focusing on investing in technology companies, with the goal of accelerating and capitalizing on tech trends reshaping entire industries ranging from construction to agriculture. The main vehicle for that has been the Vision Fund, a $93 billion investment fund launched in 2017 and backed by the likes of Apple (AAPL) and Saudi Arabia’s Public Investment Fund.

Son, famous for making an early and absurdly lucrative bet on Alibaba, informed investors that he planned to devote “97% of my time and brain” to investing in unicorn companies with the potential to be “the number one players in the market.” Skeptics, however, may have remembered another detail Son is famous, or infamous, for: losing most of his net worth when the Dot Com bubble burst.

The Vision Fund quickly rattled traditional venture capitalists, arguably drove up startup valuations and put Son and his firm in a position to exercise influence over prominent startups like Uber and WeWork. What it has yet to do is show that investing tens of billions of dollars in private companies in a relatively short amount of time – usually by making a minimum investment of at least $100 million, a figure that would have been unfathomable a decade ago – is a good and sustainable strategy.

Uber’s IPO will be “the first real litmus test” for SoftBank’s investment strategy, said Kartik Hosanagar, a professor at the Wharton School of the University of Pennsylvania. “It’s their first investment to go public and also one of their larger investments.”

But Uber may prove to be just the first of several Vision Fund investments to go public this year. Slack, a workplace communication tool, and WeWork, a coworking behemoth mostly recently said to be valued at $47 billion, have both filed to go public. SoftBank and the Vision Fund have collectively invested billions of dollars in WeWork, which Son once said could be the “next Alibaba.” (Others, however, have described WeWork in more unfavorable terms as a risky real estate arbitrage play, where it leases properties, dresses them up and looks to rent them out for more money.)

The Vision Fund scored an early win with Flipkart, India’s leading online retailer, which was acquired last year by Walmart (WMT) in a deal that reportedly pegged SoftBank’s stake at $4 billion, a 60% return from what it invested.

A high-profile win from Uber, however, could shape the narrative around the fund at a pivotal moment. Remarkable as it may sound, SoftBank is rapidly making its way through the $93 billion fund, which means it may need to raise more money to keep up its investing activity. Son has repeatedly talked about his intention to launch a second Vision Fund.

In an earnings presentation Thursday, Son said the company is “preparing for the establishment of SoftBank Vision Fund 2.” He expects many of the investors who participated in the first Vision Fund to back the new fund, but those plans may be complicated by scrutiny of Saudi Arabia over the killing of prominent journalist Jamal Khashoggi.

SoftBank is also reportedly considering the unusual step of taking the investment fund public. Son acknowledged “rumors” of a Vision Fund IPO on Thursday, but declined to comment on the matter.

“What you want to get out of each fund is some pretty early big hits because that gives you cover for whatever else happens,” said Erik Gordon, a professor at the University of Michigan’s Ross School of Business. “It keeps everyone patient and it helps you raise more money.”