A U.S. grand jury has indicted two former JPMorgan Chase & Co (JPM) traders at the center of the bank's "London Whale" scandal, court papers made public on Monday show.

Javier Martin-Artajo and Julien Grout were each charged with five criminal counts over their alleged roles in JPMorgan's chief investment office in trying to hide part of a $6.2 billion trading loss by mismarking the values of positions in a credit portfolio they managed.

Both men were charged with securities fraud, wire fraud, conspiracy, making false filings with the U.S. Securities and Exchange Commission, and falsifying books and records.

The government wants the men to forfeit proceeds traceable to their alleged offenses, including compensation from the largest U.S. bank. The case was assigned to U.S. District Judge Lorna Schofield in Manhattan.

A lawyer for Martin-Artajo did not immediately respond to requests for comment. A lawyer for Grout had no comment. Julie Bolcer, a spokeswoman for U.S. Attorney Preet Bharara in Manhattan, declined to comment. JPMorgan spokesman Brian Marchiony declined to comment.

(Reporting by Jonathan Stempel in New York)