New Zealand banks are embroiled in a global investigation into foreign exchange manipulation. Market watchdogs around the world are cracking down on the NZ$6.2-trillion-a-day foreign exchange market, after suggestions that senior traders have colluded to influence currency movements. New Zealand’s Commerce Commission has confirmed that it has its own active investigation under way. However, it would not say which banks were involved, how long it was expected to take, or explain the nature of the investigation. The commission has new powers which allow it to conduct compulsory interviews, which it is using to interview bank staff in an unrelated investigation over the selling of interest-rate swaps. New Zealand’s four biggest banks – ASB, ANZ, Bank of New Zealand and Westpac – are all Australian owned.