Its (Euronext: ALITS.NX - news) inquiry - ordered by the Department of Justice - is on top of the Securities and Exchange Commission's (SEC) investigation into the credit derivatives trade losses announced by JPMorgan last week.
The Federal Reserve - effectively the US central bank - also has a team looking at what happened.
While no reason has been given for bringing in the FBI, it is viewed in some quarters as a necessary public step, given the continuing debate in Washington over bank regulation.
It is understood the SEC is looking into the background of the trades that first drew the attention of regulators in the US and UK last month.
They will be examining exactly what top exectives, including chief executive Jamie Dimon, knew about the positions at the bank's chief investment office.
JPMorgan Chase has already accepted the resignation of its chief investment officer, Ina Drew, who was paid $15.5m (£9.6m) last year, making her one of the bank's highest-paid executives.
It is also reported that Achilles Macris, the head of the trading unit in London where the trades took place, is leaving his position.
While there is currently no evidence of criminal behaviour, Erik Gordon, a professor in the law and business schools at the University of Michigan, said that would come under the remit of the FBI.
"The FBI looks for evidence of crimes and goes after people who it alleges are criminals," he said.
"They want to send people to jail. The SEC pursues all sorts of wrongdoing, imposes fines and is half as scary as the FBI."
Mr Dimon has promised that staff found responsible for any wrongdoing will be held accountable.
He also told the bank's AGM in Tampa, Florida that their bonus payments could be clawed back.
Mr Dimon, who holds the dual role of chief executive and chairman, saw off a non-binding shareholder vote on a motion to split the two positions.
But with only 40% backing him, analysts suggested the result may have been down to the fact many investors had voted before the trading loss was confirmed.