It is just after midnight in Hong Kong, and Sam Bankman-Fried stares at the trading data on his six monitors, watching a global cryptocurrency crash happening in real time.
Mr. Bankman-Fried, a 29-year-old from California, often works around the clock, as he was on that May evening. He naps on a beanbag set up near his computer. A folded up blanket sits on the floor. He’s worth at least $8 billion, on paper.
That is even after the downturn that started in the spring, where total global losses in the value of all cryptocurrency eventually topped $1.3 trillion. And as Mr. Bankman-Fried saw it play out, he knew his business played a role in the collapse.
Cryptocurrency — digital money not backed by any nation — is famous for its wild and frequent gyrations. But FTX, the cryptocurrency trading platform that Mr. Bankman-Fried runs, specializes in a kind of trade that was accelerating the global crash.
Most of his customers are betting on future…