Ex-Credit Suisse Trader Says ‘Den of Thieves’ Chat Was Banter

A former Credit Suisse Group AG currency trader defended his use of electronic chat rooms with employees at other banks -- including one in which he described the group as a “den of thieves” -- as just banter in discussions that were otherwise vital to understanding a volatile market.

Christopher Hatton, who left Credit Suisse earlier this year, testified Wednesday in a trial over a lawsuit by a group of investors claiming the bank rigged the foreign exchange market. He said he didn’t believe anything he’d posted was a violation of policies at the time.

Credit Suisse is the ...