Major banks have suspended still-more currency traders in a sprawling probe into the guts of the foreign-exchange market, indicating that potentially questionable practices extend well beyond a single chat room, known as "The Cartel," that once appeared to be the investigation's focus.

HSBC suspended two currencies traders, a spokesperson confirmed Friday-the first time since global regulators began their examination of the market last year that the bank has taken action against employees. The traders, Edward Pinto and Serge Sarramegna, the bank's chief trader for major currencies, are both based in London. Neither could be reached for comment.