US authorities could announce this week charges against former London-based JP Morgan employees that are related to claims they tried to hide heavy losses last year, Bloomberg reported, citing an unnamed source. The trades by Bruno Iksil, nicknamed the London Whale because of the size of his holdings, eventually caused more than $6.2 billion of losses for the US bank.

The situation remains fluid and it isn’t clear who may be charged, the news service reported the source as saying.

WealthBriefing is in contact with JP Morgan seeking further details.

Those facing US charges include Javier Martin-Artajo, a former executive who oversaw the trading strategy, and Julien Grout, a trader who worked for him.  Prosecutors also are considering charges for the bank, including a fine and a reprimand, the New York Times has also reported.

The investigation has focused on whether employees at JP Morgan’s chief investment office attempted to inflate the value of trades on the bank’s books by mis-marking them, a person with knowledge of the matter said previously. Federal officials are considering charges related to mis-marking books and falsifying documents, the Bloomberg report said.

Grout, a French citizen, is in France, which may make it difficult to arrest him if he’s charged because the country has tougher extradition laws than the UK, the report continued. Martin-Artajo, a Spaniard, lives in London, according to another person familiar with the matter.

JP Morgan first disclosed losses at its London office in May 2012 after what chief executive Jamie Dimon called “egregious mistakes” in managing credit-derivative positions.

The losses were an embarrassment to the blue-blooded US bank, which has in general emerged arguably stronger from the 2008 financial crisis than many of its rivals.