Nationwide will hand back almost a million pounds to customers after it failed to warn them they would be charged before entering an unarranged overdraft.
Some 70,000 customers will get cash back after warning texts sent out by the building society didn't mention charges.
Nationwide's Sara Bennison said: “While these members haven’t been overcharged, we appreciate these texts are designed to help people avoid unarranged overdraft charges, so we apologise that on this occasion we didn’t meet the high standards we set ourselves.
"We are contacting impacted members and will be automatically refunding the charges back into their account."
Worryingly, it's the second time in 6 months that the CMA has taken action against Nationwide for breaking this Order, having secured £6 million in refunds for affected customers in August 2019.
CMA director Adam Land said: “Banks and building societies that fail to send customers text alerts saying they will be charged if they enter an unarranged overdraft are breaking the rules.
"The fact that Nationwide is a repeat offender makes it even more serious."
Nationwide isn't the only bank to fall foul of the rules - with HSBC and Santander also being told to hand back cash recently.
“This is exactly the sort of issue we would expect to fine companies for in future, if the Government gives us the increased powers we’ve asked for,” Land said.
Nationwide's Bennison said: “ From 11 November 2019, the Society removed unarranged overdraft charges, so this issue will not occur again in the future.”
