Monzo has wrongly denied refunds to thousands of fraud and scam victims, the Guardian has revealed. According to data from the Financial Ombudsman Service (FOS), the bank rejected more than 1,000 fraud complaints last year. These complaints include cases of authorised push payment (APP) scams, chip and pin fraud, and identity theft. In 2024, 34% of the 3,372 cases referred to the FOS against Monzo were found to have been wrongly rejected. This was the highest error rate among major UK banks. NatWest was second with 33% of 1,972 fraud complaints wrongly rejected, and HSBC third at 32% of 2,535 rejected cases. A Monzo spokesperson said some cases involved fraud from over two years ago. They added, “Since then, we have continued to invest in technology to stop fraud before it impacts our customers – and it’s working. We prevented 2.9 times the value of fraud in 2025 compared to the year before.” Fraud is now the most common crime in the UK, making up 41% of offences in England and Wales ending September 2024. Alex Neill, co-founder of Consumer Voice, said scam victims face stress when challenging banks. She said, “People who’ve been scammed aren’t just out of pocket, they are often left feeling worried and ashamed. Firms need to play their part and make reimbursement fair, fast and consistent, without forcing victims into a long fight for answers.” New government rules from 2024 require banks to refund most APP fraud victims. UK Finance reported 185,733 APP fraud cases in 2024, down 20% from 2023. Fraudsters stole £450.7m, while £267.1m was paid in compensation. The FOS receives hundreds of fraud complaints weekly. Monzo, founded in 2015, now has over 14 million customers after trebling its base under CEO TS Anil, who will be replaced by Diana Layfield. Last summer, Monzo was fined £21m for weak financial crime controls. FOS advises fraud victims to complain first to their bank then approach them if unsatisfied. NatWest said it prioritizes resolving complaints quickly and works closely with the FOS. HSBC stated it complies fully with reimbursements, refunding over 13,000 scam claims last year and stopping £130m in fraud losses.