So if you're this dude, how do you make this investment?

Presumably you just call your fiance guy and tell him to put a huge amount of money into Bitcoin and the order gets passed down to someone who knows what their doing and somewhere there is a PC out there with a bazillion dollars in Bitcoin sitting in cold storage?

I gotta think the end guy who makes the buy is a pretty big target for criminal types as far as figuring out where such coins are stored....

SoftBank Founder Masayoshi Son Lost $130 Million on Bitcoin

Japanese billionaire made a huge personal investment in the digital currency as prices peaked

By Rachael Levy and Liz Hoffman April 23, 2019 7:00 a.m. ET Masayoshi Son, the billionaire founder of SoftBank Group Corp. 9984 0.31% , made a huge personal bet on bitcoin just as prices for the digital currency peaked, losing more than $130 million when he sold out, according to people familiar with the matter.

Mr. Son, who launched the world’s biggest venture-capital fund on the strength of his long-term investing acumen, made the investment at the recommendation of a well-known bitcoin booster, whose investment firm SoftBank bought in 2017, the people said.

The investment came at the peak of the bitcoin frenzy in late 2017 after the digital currency had already risen more than 10 fold that year. The exact size of the bet couldn’t be determined, but bitcoin peaked at nearly $20,000 in mid December 2017 and Mr. Son sold in early 2018 after bitcoin had plummeted, the people said.

Bitcoin closed Monday at $5,381.05.

Mr. Son is known for quick investment decisions and big risky bets, most of which have paid off. He decided to back Alibaba Group Holding Ltd. after spending just five minutes with its founder, Jack Ma. He took a half-hour to greenlight a $200 million investment in a startup that grows vegetables indoors.

Mr. Son’s previously unreported loss shows that even some of the world’s most sophisticated and wealthiest investors got caught up in the frenzy. With a net worth estimated by Bloomberg LP at $19 billion, Mr. Son will hardly notice, though it dents his reputation as a patient and prophetic investor.

A SoftBank spokesman declined to comment on Mr. Son’s behalf.

Mr. Son was encouraged to make the investment by Peter Briger, the co-chairman of asset manager Fortress Investment Group, the people said. SoftBank bought Fortress in February 2017, inheriting the asset manager’s bitcoin reserves along with its more traditional investment funds.

Fortress under Mr. Briger first bought bitcoin in 2013, when it was still a fringe technology used mainly in the darker corners of web commerce. By the time the SoftBank deal was completed, its holdings were worth more than $150 million.

Mr. Briger declined to comment through a spokesman.

Mr. Son built SoftBank mostly on long-term technology investments and used his record to launch the $100 billion SoftBank Vision Fund. The fund, backed by the government investment fund of Saudi Arabia, owns big stakes in Uber Technologies Inc. and WeWork Cos., and has been credited with driving up valuations of some of the biggest private technology companies.

The Vision Fund is facing a test of its success with the coming initial public offering of Uber, which is aiming for a valuation of as much as $100 billion, below previous expectations but still above where the fund invested.

Even as it looks ahead to futuristic technology, SoftBank’s most immediate problem is its controlling stake in U.S. mobile phone company Sprint Corp. The 2013 deal has weighed down the conglomerate with debt, limiting its investing options.

Last week The Wall Street Journal reported that Sprint and T-Mobile’s merger had been challenged by U.S. Justice Department staff lawyers, who expressed concerns that the all-stock deal would threaten competition.

Sprint, hoping for approval, said in a regulatory filing last week: “Sprint is in a very difficult situation that is only getting worse. Sprint is not on a sustainable competitive path.”