Whether a federal jury in New York convicts Sam Bankman-Fried of fraud and money-laundering or not, his trial provides a vivid case study in the excesses of American business and finance. (He has pleaded not guilty.) FTX, Mr. Bankman-Fried’s company, cultivated a reputation as the mainstream, responsible face of the generally regulation-averse cryptocurrency movement. That was a facade: At its peak, FTX, the alternative currency marketplace Mr. Bankman-Fried, now 31, co-founded in 2019, had a valuation of $32 billion. Three years after its founding, it was bankrupt, having succumbed to a classic bank run after reporting on the company’s financial arrangements suggested potential insolvency. When a new court-appointed management looked over the books, $8 billion of FTX customers’ deposits turned up missing. Much of that money had gone toward self-interested purposes such as Bahamas real estate, or personal loans to company insiders, according to a Wall Street Journal investigation.