Another hefty rise could be the final catalyst and force banks to move, said Chirantan Barua, an analyst at Sanford C. Bernstein.

HSBC, which has described the levy as a tax on staying in London, faces a bill of $1.5 billion this year, about 7 percent of expected profits. Standard Chartered is set to pay $500 million, or about 9 percent of earnings.

HSBC says it has two home markets, Britain and Hong Kong. It moved from Hong Kong to London in 1993 when it bought Midland Bank, and its most likely move would be back to its former home, one of the few places that could handle its $2.6 trillion balance sheet.

The bank began life in Hong Kong 150 years ago, with roots in financing trade between Europe and Asia. It issues most of the territory’s bank notes and has made $24 billion in profits there over the past three years, compared with a $4 billion loss in Britain over the same period.

London has been home to Standard Chartered since it was formed in 1969, and its most likely new home would be Singapore, from where most of its businesses are already run.

Analysts said the cost of moving could be between $1.5 billion and $2.5 billion per bank.

HSBC told British lawmakers in February, before the tax increase, that the best location was still Britain. It postponed a review in 2011 because its chief executive, Stuart Gulliver, said there were too many moving parts to make a rational decision.

Industry sources said that could still be the case for both banks. They are trying to improve profitability, cut costs, sell businesses, deal with old misconduct issues and simplify. Standard Chartered also gets a new chief executive this year, Bill Winters, who may want to raise capital.