Between 2016 and 2018, cryptocurrencies produced a bona fide financial bubble. Nothing typified the madness better than the craze for initial coin offerings meant to fund software projects that promised to revolutionise everything from online gaming to file storage. Maybe you invested. More likely, you intuited something was awry when your Uber driver started asking for crypto recommendations and a friend began touting a blockchain-based ledger designed to track marijuana supply chains.

ICOs birthed a thousand millionaires before asset prices plummeted in late 2018, and parts of the sector still thrive. Now regulators at the US Securities and Exchange Commission are beginning to grapple with the problems caused by these investments through a series of enforcement actions.

So far, the watchdog has focused on bringing ICOs under its traditional regime of disclosure-based investor protection rules. But my research with David Wishnick into the ICO market reveals some disquieting facts.