Earthquakes seldom hit the British Isles. But one did late Thursday night and early Friday morning, as the constituency returns started pouring in on the referendum to decide whether the United Kingdom would Remain in or Leave the European Union.

Most polls had shown a small margin for Remain, and betting markets made it an odds-on favorite. Hedge funds went long on the assumption Remain would win. It had the support, after all, of Conservative Prime Minister David Cameron, the leftist Labour leader Jeremy Corbyn, Bank of England president Mark Carney and the financial leaders of the City of London.