The JPMorgan Chase executives who supervised the traders at the center of the "London Whale" scandal are unlikely to face any charges over a trading debacle that cost the largest U.S. bank more than $6.2 billion.

Federal prosecutors brought criminal charges against two former JPMorgan traders - Javier Martin-Artajo and Julien Grout - accusing the pair of deliberately understating losses on the trades on JPMorgan's books.

The complaints make only passing reference to their former bosses. Neither Ina Drew, the bank's former chief investment officer, nor Achilles Macris, a former top Chief Investment Office executive, are mentioned by name in the complaints filed in New York.

The filings refer to Drew and Macris only by their titles and said they put pressure on their subordinates at one point to deal with the high degree of risk being taken on in the portfolio of derivatives trades that led to the losses.

There is no allegation in the complaints that either Drew or Macris did anything wrong or encouraged Martin-Artajo and Grout to conceal the losses, which first began to be publicly disclosed in May 2012.

Bruno Iksil, the trader most identified with the losses, is cooperating with federal prosecutors in an agreement which means he will not face charges. Iksil was known as "the London Whale" because of the size of derivatives trades he made.

US Attorney Preet Bharara, when asked by reporters about the prospect of additional actions against higher executives, said: "These are the charges we have brought". He said that the investigation is ongoing.

That the two senior executives may emerge from the year-long investigation unscathed is a sign that the scandal may not do much additional damage to the bank's image or the reputation of its chief executive, Jamie Dimon.

Drew, who resigned when the losses became public, was once a member of Dimon's elite operating committee of executives. She was criticized in the company's internal investigation for failing to understand the risks the London traders had been taking as they made $2 billion in profits over several years.

The bank also said she did not ensure that the mechanisms to monitor the risk being taken on by her traders were working.