GENEVA—Some of Switzerland's largest banks have begun transferring requested information to the U.S. Department of Justice on their dealings with U.S. clients suspected of tax evasion.

The information transfer is part of an arrangement unveiled by the Swiss government July 3 to facilitate settlements between the banks and U.S. authorities.

A spokesman for Credit Suisse, Switzerland's second-largest bank, confirmed July 26 that the bank “applied for, and received permission” from the Swiss government to hand over information on its “leaver list” of U.S. client activity.