Anyone who has taken an Uber, sent a Slack message or enjoyed a free beer at a WeWork owes a little something to Masayoshi Son.
Through his Japanese conglomerate SoftBank and a $100 billion investment fund, Mr. Son plowed huge sums into these and other companies that aim to change how people work, travel and live. His investments enabled the young companies to throw caution to the wind and run up big losses as they expanded at a breakneck pace in recent years. Even in the start-up world, where idealism is abundant and losses are a badge of honor, Mr. Son’s approach and ambition stood out.