JPMorgan sues former London Whale boss-report

Oct 31 (Reuters) - JPMorgan Chase & Co has filed suit 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 this year, according to a published report.

Javier Martin-Artajo, who was Iksil's immediate supervisor, was named a defendant in a London lawsuit filed Oct. 22 and made public on Wednesday, Bloomberg News reported. The court filings did not reveal any details of the complaint, the news service said.

JPMorgan executives said in July the bank would act to take back pay from traders and supervisors involved in the loss. Those included Iksil, Martin-Artajo, and Achilles Macris, who was Martin-Artajo's boss.

A JPMorgan spokeswoman in New York declined to comment.