Many investors would back HSBC if it chose to move its headquarters from London as a result of continuing regulatory frustrations, one of the banking giant's shareholders has claimed.
Standard Life equities head David Cumming said HSBC could be "very close to losing patience" as banks are being required to meet "ever-increasing capital requirements".
Standard Life owns just over 1% in the bank.
HSBC has threatened to quit the UK over frustrations with its regulatory environment, with Hong Kong seen as the most likely alternative.
Speaking to the BBC today, Mr Cumming said that Standard Life "along with a lot of other shareholders" would be supportive of a move from the UK.
Next month, the Bank of England is set to issue its latest stress tests, designed to check whether banks could withstand another financial crisis.
Mr Cumming has accused the regulators of constantly "moving the goalposts" with reference to the levels of capital lenders are required to hold.
"Obviously we need stress-tests and banks should have prudent capital.
"But I think this ongoing process of continually... moving the goalposts and with the Financial Policy Committee coming up with new wheezes in terms of getting the banks to hold more capital - I think HSBC are very, very close to losing patience with this never ending process.
"And I think a lot of shareholders, including ourselves, would be supportive of them moving, given the current situation in terms of regulation."
Over the summer, chancellor George Osborne said he would gradually reduce the banking levy, a way of forcing banks to contribute more to the UK economy, and introduce an 8% surcharge on UK profits instead.
This was seen as an attempt to encourage HSBC to remain in the country.
The banking giant is already in the process of relocating the head office of its UK retail banking operations from London to Birmingham by 2018 ahead of new ring-fencing rules separating this part of the group from its investment arm.
This part of the bank will hold 22,000 UK staff.