US attorneys in New York are dropping the cases against Julien Grout of France and Javier Martin-Artajo of Spain, who were accused of being key figures in covering up $6.2 billion (€5.7 billion) in trading losses at JPMorgan Chase in a scandal that blew up in 2012.
US officials said a Spanish court rejected efforts to extradite Martin-Artajo, "and a prior determination had been made that attempts to extradite Grout from France would have been futile," said acting US attorney Joon Kim.
Kim also said prosecutors could "no longer rely" on testimony of Bruno Iksil, the trader who nicknamed the "London Whale," based on "a review of recent and statements made by Iksil."
A judge must approve the motion to dismiss the case.
US federal prosecutors filed criminal charges in 2013 against Martin-Artajo and Grout, alleging they kept false records on trades, committed wire fraud and submitted false US securities filings when they worked for the bank in London.
Iksil was cleared of criminal responsibility after cooperating with prosecutors.