Betfred will face a fine of £322,000 ($395,000) after a Gambling Commission (GC) investigation found the operator failed to carry out adequate source of funds checks on a customer.
Over a 12-day period in November 2017, a Betfred customer deposited £210,000 and lost a total of £140,000.
The customer, who has since been convicted of £2m worth of fraud, had been spending stolen money through several gambling operators, including Betfred.
Petfre Limited, operating as Betfred, will return £140,000 to the identified victim, while £182,000 will go towards the GC’s national strategy to reduce gambling harm.
The GC said: "The management of this customer in relation to anti-money laundering (AML) raised significant concerns regarding the effectiveness of the policies and procedures that Petfre had in place and its management of risks to the licensing objectives."
Despite the failings, the GC is confident Betfred acknowledged the errors and has improved its AML procedures since the time in question.
A spokesperson from Betfred told Gambling Insider: "As noted by the GC, this was an isolated incident concerning one individual over a short period in November 2017.
"We have subsequently reviewed and strengthened our anti-money laundering policies, procedures and controls."