Revolut has had the highest number of fraud and scam complaints escalated to the Financial Ombudsman Service (FOS), according to data obtained by Which?.

The consumer champion analysed cases of authorised push payment fraud (APP) and other scam or fraud complaints.

It found that in 2024, the digital bank had 3,242 APP-related complaints submitted to the FOS.

Revolut was closely followed by fellow challenger bank Monzo, with customers sending the ombudsman 2,344 APP complaints in total.

Barclays came in third, with 1,704 recorded APP complaints over the 12-month period.

APP fraud involves a customer being tricked into sending money to a scammer by bank transfer while unauthorised fraud involves criminals stealing money by hacking into accounts using stolen card details and committing identity fraud.

During the same year, the FOS received 2,631 other fraud and scam complaints from Revolut customers. The bank was again followed by Monzo with 1,810 complaints, and Barclays with 1,461 complaints.

In 2025 so far, the FOS has received 1,875 complaints from Revolut customers, 1,161 complaints from Barclays customers and 1,063 complaints from Monzo customers.

The consumer champion said that with 40 per cent of the complaints by Monzo customers being upheld by the FOS over the past nine months, this could indicate that its customers are the most likely to have been wrongly denied reimbursement over the period.

During 2025 so far, 31 per cent of the claims against Barclays were upheld, while the FOS upheld 30 per cent of the claims against Revolut.

Responding to the figures, a spokesperson for Revolut told Which? that the company has robust protections in place to analyse over a billion transactions per month and it takes fraud incredibly seriously.

“Each potential fraud case concerning a Revolut customer is carefully investigated and assessed independently of other cases and we also revisit liability considerations as a result of complaints wherever any errors are identified during the complaints review,” the spokesperson added. “Our Financial Crime prevention team now makes up more than a third of our total global workforce of 10,000+ employees, and half of the data scientists at Revolut are working on Financial Crime-related topics or products.”

It added that the company has developed “sophisticated AI models” capable of spotting and blocking potentially fraudulent transactions using hundreds of internal and external data points.

In 2024, the bank says it prevented over £600 million of potential fraud against its customers.
A spokesperson for Monzo told Which? that fraud is an industry-wide problem, with people losing £1.17 billion to fraudsters nationwide in 2024 alone.

“At Monzo our priority is to stop fraud before it impacts our customers – and it’s working,” they added. “We prevented 2.9 times the value of unauthorised fraud in FY2025 compared to the year before and we continue to prioritise investing heavily to protect our customers, leveraging our unique position as a fully regulated bank with cutting-edge technology to stop fraudsters in their tracks.”

Barclays told Which? that protecting its customers from fraud and scams is its highest priority, adding that the company continues to work closely with the wider industry to tackle this crime.

“In the unfortunate cases where our customers do fall victim to fraud, we work hard to reach the right outcome and provide them with the support they need during a difficult time,” they added. “We’re committed to providing excellent service and we continue to make progress both in reducing the number of complaints referred to the FOS and improving the uphold rate for our decisions.”

---