HSBC has suspended two London-based foreign exchange traders as an investigation into the possible rigging of global currency dealing deepens.
The bank said late last year that it was one of a number of leading finance houses being scrutinised by international regulators.
Others being investigated include Citigroup, JP Morgan, Barclays, UBS and Deutsche Bank.
Citigroup was also said on Friday to have suspended currency traders.
US regulators came to the UK this week.
They are working with UK regulators to ascertain whether traders worked together to rig global currency values.
The market is worth more than $5 trn (£3 trn) dollars a day.
Barclays and RBS are among the major banks that have already suspended traders.
The probe centres on senior traders' communication of client trades through electronic chatrooms.
These were also a central feature of an investigation into the manipulation of the interest rates, such as Libor, used as benchmarks for lending rates across the board.
Many of the world's leading banks have been fined for rigging rates.
The UK's Financial Conduct Authority began a formal investigation into the currency market in October.