Last month Kevin Guo, co-founder of Dianrong, a fintech company in Shanghai, began to invest in Chinese “initial coin offerings” that sell investors digital tokens in exchange for virtual currency such as bitcoin.

Mr Guo scanned WeChat groups, attended forums in Shanghai and exchanged ideas with others who shared his interest. He read white papers and other documents from dozens of issuers and eliminated those he thought would be vulnerable to manipulation or whose technology was particularly iffy before he selected a few to invest in.

Then earlier this week, after an unexpectedly tough regulatory clampdown in China, Mr Guo received an inquiry from one of the ICOs he had selected. The founder was shutting down on the mainland and was offering him two choices. He could have his money back or hang on until the entrepreneur re-launched the offer from another jurisdiction.