No one wanted to miss out on the cryptocurrency mania.

Over the past two years, as the prices of bitcoin and other virtual currencies surged, crypto startups proliferated. Companies that market digital coins to investors flooded the airwaves with TV commercials, newfangled lending operations offered sky-high interest rates on crypto deposits and exchanges like Coinbase that allow investors to trade digital assets went on hiring sprees.

A global industry worth hundreds of billions of dollars rose up practically overnight. Now it is crashing down.