The Financial Conduct Authority (FCA) is "working closely" with HSBC and other agencies to ensure current cultural practices fall in line with standards, following allegations that the bank helped its clients engage in tax avoidance.
"This has served to reinforce the importance of firms operating with the right culture across all of their operations," the FCA said in its first public statement on the matter.
"The FCA is working closely with the firm and other agencies which have an interest in this matter to ensure that any questions this may raise in relation to any current practices and culture of HSBC are addressed."
HSBC has referred to its four-page statement, which it published on its website last week, and said it is co-operating with the relevant authorities.
Reports that HSBC's Swiss unit helped hundreds of people avoid paying tax were made by a collaboration of news outlets including Le Monde, The Guardian, the International Consortium of Investigative Journalists and the BBC's Panorama.