An incoming UK levy on bank balance sheets, plus tougher British and European limits on bankers' pay, is causing "a lot of concern" at HSBC.
Speaking after the group posted a positive third-quarter trading update, incoming chairman Douglas Flint said shareholders were pressing the group to consider whether the price of staying in London was too high.
"They are asking us to evaluate what the regulatory changes are likely to cost and what impact it will have on our business model," said Flint, currently finance director.
HSBC, which earlier this year appointed a new senior management team after a damaging boardroom brawl, said prospective employees were concerned that the bank wasn't in control of its own remuneration policy. This is creating recruitment difficulties in emerging market countries such as Brazil and China, where HSBC says it is losing the race for talent to rivals operating under less restrictions.
This is expected to particularly hit staffing in the group's investment banking arm after annual bonuses are paid next spring, leaving employees free to seek higher pay elsewhere.
"It creates a huge problem for an international company to not be able to pay market pay across the world," said Michael Geoghegan, HSBC's outgoing chief executive.
The group's regular three-year evaluation of its headquarters is due next year. Geoghegan has been based in Hong Kong since last year, and his replacement, investment banking head Stuart Gulliver, is also expected to operate from there.
The Financial Services Authority has already introduced new guidelines limiting bonuses, while even tougher EU rules on variable pay are set to come into effect from January 1.