HSBC Friday said it was considering moving its headquarters out of Britain, following regulatory and structural reforms.
Britain's largest bank said it had not yet decided where it might move its headquarters.
"The question is a complex one and it is too soon to say how long this will take or what the conclusion will be, but the work is under way," said the bank in a statement.
Douglas Flint, HSBC's chairman, told those at the bank's annual meeting on Friday the decision was part of a "broader strategic review taking place" at the bank.
"As I said at our informal meeting in Hong Kong on Monday, we are beginning to see the final shape of regulation and of structural reform, including the requirement to ring-fence in the UK," Flint said.
"The board has therefore now asked management to commence work to look at where the best place is for HSBC to be headquartered in this new environment," said Flint.
Reports said HSBC may move its headquarters back to its former home in Hong Kong.
The Hong Kong Monetary Authority (HKMA) has welcomed HSBC's decision to conduct an immediate review into whether it would move its headquarters from Britain.
"The HKMA takes a positive attitude should HSBC consider relocating its headquarters back to Hong Kong," it said.
Last month, HSBC announced it would move the headquarters of its personal and business arm from here to Birmingham. That means the bank would relocate 1,000 staff from the capital.
