FILE PHOTO - A sign is pictured in front of the Vitol Group trading commodities building in Geneva October 4, 2011. Picture taken October 4, 2011. REUTERS/Denis Balibouse

LONDON (Reuters) - Global energy trader Vitol faces a possible fine of $6 million from a U.S. energy regulator for alleged manipulation in California’s power market, an order from the regulator showed.

“The Commission directs Vitol to show cause why it should not be required to disgorge unjust profits of $1,227,143, plus interest,” the Federal Energy Regulatory Commission (FERC) wrote in an Order to Show Cause.

The FERC alleges that Vitol and an employee purposefully sold physical power at a loss in the market run by the California Independent System Operator.

The employee faces a possible $800,000 fine.

Vitol’s U.S. subsidiary said it “regrets the FERC’s decision to issue an Order to Show Cause against it and denies all of FERC’s allegations.”

In the order filed on July 10, the FERC states the alleged manipulation took place in 2013. Vitol has 30 days to respond.