British authorities investigating potential manipulation in the currency markets are looking at the role of a senior trader at JPMorgan Chase & Co. while he worked for another firm, the Wall Street Journal reported on its website on Monday.

The bank's London-based head of spot currency trading participated in certain electronic chat sessions while at his former employer, Royal Bank of Scotland Group PLC, that authorities have homed in on, the WSJ said.

The chat sessions were with a group of traders from other banks who were called "The Bandits' Club" and "The Cartel," the WSJ said.

Reuters reported last week that Royal Bank of Scotland had handed Britain's financial regulator instant messages sent by a former currency trader to counterparts at other banks, but could not verify the identity of the former trader.

Investigations into the $5 trillion-a-day market have broadened, with authorities in Switzerland and Britain looking into whether traders at banks sought to manipulate benchmark foreign currency rates.

JPMorgan spokesman Brian Marchiony declined comment.