Japan's Mitsubishi UFJ Financial Group (MUFG) has decided to shift its European Union investment banking base from London to Amsterdam, according to reports.
Citing sources, the Reuters agency reported that MUFG would also open an investment banking branch in the French capital Paris.
The move would see "several dozen people" moved to either Amsterdam or Paris from London, the report said.
Japan's largest bank employs more than 2,000 people at its European investment banking head office in London, with sources saying that the British unit would continue to function as headquarters for Europe, the Middle East and Africa.
In a statement released on 13 September, MUFG insisted that there was no change to its commitment to the UK and EU securities markets.
"We will be establishing a new subsidiary of MUFG Securities in Amsterdam to minimise uncertainty arising from the UK's exit from the EU, and transferring some functions of our securities business there," it said.
"We are working closely with regulators to ensure that we reach a solution that is in the best interests of our clients."
Several major banks and financial institutions have outlined plans to shift jobs away from London due to the uncertainty surrounding Brexit negotiations.
The UK is due to leave the European Union in March 2019, with Brexit Secretary David Davis formally beginning talks with his EU counterpart Michel Barnier over negotiating the exit in June.
A so-called "hard Brexit" would likely mean the loss of passporting rights for British financial institutions, which allow banks based in the UK to offer services to companies and governments across the European Union without restrictions.
There are fears that this could lead to an exodus of banks from London to other European cities.
The Financial Conduct Authority (FCA), the City's top regulator, warned earlier this summer that firms were nearing the point where they have to take action to ensure that their business is not disrupted after the UK leaves the EU.
FCA chief executive Andrew Bailey said it was difficult for financial firms to make plans regarding Brexit without having a clear idea of what the outcome of negotiations between the UK and EU would look like.
"In order to have things in place by two years' time, [firms] have got to start implementing plans [by the end of this year]," he said. "Agreement on a transition would break that constraint. I do think this is important."