[LONDON] Britain voted last month to leave the EU, raising questions about whether banks and investment firms will continue to have access to the bloc's single market or which rules would apply.
"As a starting point, I would emphasise that the UK remains a member of the EU until such time as things change, and so all our rules continue to apply, whether they originate in the EU or not," Financial Conduct Authority (FCA) chief executive Andrew Bailey said.
"Likewise, we will continue to implement EU legislation until the future is clear, something that is again a legal requirement," Mr Bailey told his first annual meeting of the FCA as chief executive.
He welcomed the government's statement that Britain would seek access to the single market in coming trade negotiations.
Mr Bailey also "valued" being able to recruit staff from across the world.
The UK government has not guaranteed EU citizens in Britain will be allowed to stay after the country leaves the bloc.
"These are unsettling times, and we owe it to people who work so hard to support us to put their minds at rest," Mr Bailey said.
He added the FCA was working on a new mission statement which it hoped to publish in the early autumn for consultation.
The watchdog has been criticised by some in the financial industry for being overly protective of consumers who make bad choices, and Mr Bailey's predecessor Martin Wheatley was ousted by the government for being too hardline.
"How to balance the duty of care towards consumers, the duty of responsibility of consumers for their decisions, the role of firms and the role of the regulator, is an inherently difficult question to which there will be many potential answers."
"It lies at the heart of the FCA's mission. So far I would say it has not been adequately answered," Mr Bailey said.
Mr Bailey added the EU's cap on banker bonuses, a measure Britain had opposed, would also remain in place until the outcome of trade negotiations were known.
Brexit won't mean a "bonfire of regulations," he said.