Deutsche Bank, Citigroup and five of their senior bankers have been formally charged with criminal cartel offences by an Australian finance watchdog, in the latest of a series of regulatory blows to the banks' international reputations.

In a statement on June 5, the Australian Competition and Consumer Commission said it was bringing charges against the two global banks alongside the Australia and New Zealand Banking Group, accusing them of "cartel arrangements" relating to trading in the latter's shares during an institutional placement in August 2015.