JPMorgan Chase is to move hundreds of staff from London to its European offices as the UK prepares to leave the European Union, with the EU warning initial Brexit costs may reach €100bn.
According to Bloomberg, the firm is planning to move bankers to Dublin, Luxembourg and Frankfurt, where the bank already has existing operations.
Daniel Pinto, head of investment banking, said: "We will have to move hundreds of people in the short term to be ready for day one, when negiotiations finish, and then we will look at the longer-term numbers."
Prior to the referendum, JPM chief executive Jamie Dimon warned as many as 4,000 employees could be relocated if Britain voted to leave the EU.
"We have to plan for a scenario where there is no UK/EU passporting deal and we have to move a substantial portion of our business to continue serving our European clients," said Pinto.
According to economic thinktank Bruegel, the UK could lose 10,000 banking jobs and a further 20,000 roles in financial services thanks to Brexit.
As well as JPM, other banks including Standard Chartered, Deutsche Bank, Goldman Sachs and Morgan Stanley have indicated they could relocate positions.
The EU has also raised the cost for the Brexit bill to €100bn, according to the Financial Times, maximising the liabilities Britain is asked to cover.
This is an increase from the initial estimate of €40bn-€60bn and covers issues such as EU administration fees and post-Brexit farm payments.
Estimates are highly variable depending on when the UK actually leaves the bloc, the type of liabilities it is required cover and its proper share of contributions.
Michael Barnier, the EU's chief negotiator, is expected to unveil a draft negotiating mandate on 3 May.
He said no final figure will be set until the end of the Brexit process and the payments could be staggered, but Britain must agree to a methodology before trade talks begin.