The Hongkong and Shanghai Banking Corporation said in a note to the London Stock Exchange following a board meeting yesterday that London's many advantages meant it was "ideally positioned" to provide a home base.
"Having our headquarters in the UK and our significant business in Asia Pacific delivers the best of both worlds to our stakeholders," group chairman Douglas Flint told BBC radio.
It made no reference to growing fears in Hong Kong that the city's freedoms are being eroded by an increasingly influential China, a trend observers say could damage its status as a freewheeling finance hub.
It also cited as a reason for the review the British bank levy introduced in 2010 -- a tax based on the size of any British-based banks' global balance sheet which has since been scaled down.
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A British finance ministry spokeswoman said the decision was "a vote of confidence in the government's economic plan and a boost to our goal of making the UK a great place to do more business with China and the rest of Asia".
The decision will come as a relief to the City, where bank stocks have suffered this year and there is growing concern about uncertainty from a referendum on Britain's EU membership expected this year.
"London is one of the world's leading international financial centres and home to a large pool of highly skilled, international talent," the bank's statement said.
"It remains therefore ideally positioned to be the home base for a global financial institution such as HSBC," it said, adding that the board decision was "unanimous".
The bank's Hong Kong-listed stock rising also rose more than four percent at closing.
"This decision is a big vote of confidence in the UK," a spokesman for the British Banking Association trade body said, underlining that banking is "an internationally mobile industry".
"We cannot afford to be complacent about the contribution banking makes to the British economy, a sector that employs over half a million people".