LONDON - Switzerland’s Competition Commission said on Monday that it had begun a formal investigation into eight financial institutions, including the Swiss banks Credit Suisse and UBS, over potential collusion to manipulate the currency markets.
In a statement, the regulator, also known as Weko, said it was “examining whether there have been impermissible collusion in fixing various exchange rates in the foreign exchange market between different banks.â€
The investigation is examining whether banks trading currencies also exchanged confidential information and coordinated their actions in order to influence key foreign exchange benchmarks.
The financial institutions are UBS, Credit Suisse, Zürcher Kantonalbank, Julius Baer, JPMorgan Chase, Citigroup, Barclays and Royal Bank of Scotland.
The regulator opened a preliminary investigation into the foreign exchange market last year.
R.B.S. said it would “cooperate fully with any regulatory investigation.â€
Julius Baer, the Swiss private bank,  said it would â€constructively support†the investigation.
UBS, Barclays, Citigroup and JPMorgan declined to comment on Monday. Credit Suisse did not immediately have a comment when reached on Monday.
Zürcher Kantonalbank said it would cooperate with the investigation, and that it plays a “minor role†in the spot currency market.
Regulators in Britain, the United States and other countries have begun investigations into whether traders tried to manipulate closely watched benchmark currency rates.
More than two dozen traders have been placed on leave or fired as a result of internal investigations at several large financial institutions involved in foreign exchange trading, including Barclays, JPMorgan and R.B.S.
Last week, UBS placed on leave three traders in New York, two in Zurich and one in Singapore as part of its internal review, according to people familiar with the matter who were not authorized to discuss it publicly. The bank last year suspended a senior currency trader in Zurich.
Deutsche Bank, the largest player in the currency trading market, with a share of about 15 percent, and Citigroup have each fired employees as a result of their own investigations.
The Bank of England also has suspended an employee as it conducts an internal review into whether central bank officials knew of, or condoned, manipulation of the currency markets.
None of the banks, or any of the suspended or fired traders, has been accused of wrongdoing by the authorities.
