Barclays Bank has been fined £26m by UK regulators after one of its traders was discovered attempting to fix the price of gold.
The incident occurred in June 2012, the day after the bank was fined a record £290m for attempting to rig Libor.
Barclays said it "very much regrets the situation" that led to the fine.
The FCA found the bank failed to "adequately manage conflicts of interest between itself and its customers", in relation to fixing the price of gold.
The FCA also fined the trader, Daniel James Plunkett, £96,500.
"A firm's lack of controls and a trader's disregard for a customer's interests have allowed the financial services industry's reputation to be sullied again," said Tracey McDermott, the FCA's director of enforcement and financial crime.
Mr Plunkett was a director on the precious metals desk.
He was responsible for pricing and managing Barclays' risk on a contract that was specifically linked to the price of gold at 3:00p.m. on 28 June 2012.
If the gold price was above $1,558.96 at that time then Barclays would be required to make a payment of $3.9m to its customer.
But if the price was below that benchmark Barclays would not have to make the payment.
Mr Plunkett created fake orders with the intent of pushing the price of gold below $1,585.96, which he succeeded in doing.
The result was Barclays was not obligated to make the $3.9m payment to its customer, and Mr Plunkett booked a profit of $1.75m for the bank.
