The Competition and Markets Authority (CMA) in the UK has warned four banks for breaching transaction history-related regulations.

According to the Retail Banking Market Investigation Order 2017, all financial institutions are required to send current account banking transaction histories to former customers.

The procedure must be completed within 40 days of a customer or small business closing their current account. The regulation also requires the banks to send the data to 95% of such customers within ten days.

However, CMA found that Monzo, Bank of Ireland, NatWest Group and Virgin Money violated the regulations.

Overall, around 150,000 customers did not receive their transaction history within the necessary timeframe. Monzo alone accounts for majority of these breaches failing to deliver banking data to more than 143,000 former account holders.

Some of these breaches were delayed by a few weeks, while others were not provided even after a year.

CMA was already written to all four banks and would initiate further action if they violate the regulations again.

The steps may include organising training or carrying out annual compliance audits.

CMA Remedies Business and Financial Analysis senior director Adam Land said: “Nearly 150,000 people were affected by these banks’ breaches, with the majority being former Monzo customers. This may have made things harder for people trying to borrow money or apply for a mortgage.

“The CMA’s work in the sector is making it easier for people to get a better deal from their bank. Banks must comply with all the rules – that includes providing a full transaction history promptly.

“We will be watching closely to make sure these leading names stick to their word and don’t let their customers down again. The Bank of Ireland, Monzo, Natwest Group, and Virgin Money should be in no doubt that the CMA stands ready to take further action if these failures are repeated.”