London-based banks HSBC Holdings Plc and Standard Chartered Plc tumbled in Hong Kong after early results from Britain’s European Union referendum indicated greater support for an exit than academics had forecast.

HSBC, which made about a third of its 2015 revenue in Europe, fell as much as 3.1 percent and Standard Chartered as much as 3.7 percent.

HSBC was down 1.2 percent and Standard Chartered by 1.7 percent as of 9:42 a.m. local time. The city’s benchmark Hang Seng Index was little changed.

Financial institutions including JPMorgan Chase & Co., HSBC and Deutsche Bank AG warned ahead of Britain’s vote that they could shift some operations from London if the U.K. left the EU. HSBC would probably move about 1,000 investment bankers to Paris in the event of an exit, Chief Executive Officer Stuart Gulliver said in February.

It was only four months ago that HSBC said it will maintain its headquarters in London, a move that helped underscore the city’s status as a global financial hub. The decision, which followed 10 months of deliberations, came after the bank secured concessions from the U.K. government on regulation and taxes.