The Financial Conduct Authority (FCA) is investigating the 2012 Royal Bank of Scotland (RBS) IT outage that locked customers out of their accounts, costing the bank a massive £175m in compensation payments.
The FCA confirmed it was investigating the incident and whether to take action against RBS in a statement on Tuesday.
"The FCA will reach its conclusions in due course and will decide whether or not enforcement action should follow that investigation," it said.
If the FCA determines the outage was caused by negligence then RBS could face an unlimited fine. The outage was the result of an IT failure in RBS' systems that halted the overnight transfer of money between accounts
The failure led to a backlog of payment requests and stopped millions of customers from receiving or making payments for almost an entire week. The incident was so bad that RBS considered taking legal action against CA Technologies, the software vendor that manages RBS's CA-7 automation software.
An RBS spokesperson told V3 the bank has upgraded its systems to ensure a similar outage does not occur.
"Last summer's IT failure was unacceptable. We have already made significant improvements and over the next three years will invest hundreds of millions in our systems" said the spokesman.
"We will be working closely with our regulators in the UK and the Republic of Ireland. Our customers deserve a service they can rely on 100 percent of the time and that's what we want to provide."
Despite the upgrade RBS suffered a three-hour outage that stopped a some customers taking out cash earlier in 2013.
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