JPMorgan Chase & Co. has filed a suit in a British court against the former boss of Bruno Iksil, the trader known as the London Whale, for the outsized derivatives positions he took that cost the bank $6.2-billion (U.S.) in losses this year.
Javier Martin-Artajo, who was Mr. Iksil's immediate supervisor, was named a defendant in a London lawsuit filed on October 22.
Details of the court filings, which were first reported by Bloomberg News, will not be released until the defendant acknowledges the claim, the court said.
JPMorgan executives said in July the bank would act to take back pay from traders and supervisors involved in the loss. Those included Mr. Iksil, Mr. Martin-Artajo, and Achilles Macris, who was Mr. Martin-Artajo's boss.
A JPMorgan spokeswoman in New York declined to comment. Martin-Artajo's lawyer could not immediately be reached for comment.