Masayoshi Son lost $130M on Bitcoin — the billionaire's worst trade

Masayoshi Son, the founder and CEO of SoftBank Group, is one of Japan's most famous investors, known for early bets on Alibaba and Yahoo. In late 2017, at the peak of the cryptocurrency mania, Son made a personal investment in Bitcoin.

Son bought Bitcoin near the top of the market in 2017. When the cryptocurrency bubble burst in early 2018, Bitcoin crashed from nearly $20,000 to around $3,000. Son's personal position lost approximately $130 million — the largest personal trading loss of his career.

The loss was kept private for over a year. It only became public in April 2019, when the Wall Street Journal reported that Son had lost $130 million on Bitcoin. According to the report, Son had told associates he was 'agitated' by the loss.

The case was notable because it showed that even one of the world's most successful investors could be swept up in a speculative mania. Son, who built his fortune on long-term conviction bets, made a short-term speculative trade at the peak of a bubble — and paid the price. For a man whose net worth was estimated at $20 billion at the time, the loss was small, but for someone who rarely loses money on personal trades, it was a humbling moment.