The Justice Department is investigating whether JP Morgan Chase manipulated US energy markets, according to people familiar with the case, marking the latest legal hurdle for a bank already facing a mountain of litigation and regulatory scrutiny.

JP Morgan last month agreed to pay $410 million to settle allegations raised by the Federal Energy Regulatory Commission that the bank manipulated markets in California and the Midwest. JP Morgan, the nation's largest bank by assets, didn't admit to wrongdoing as part of the settlement.