Visa is being investigated by the European Commission over its rules for fintech firms regarding digital wallets, The Times reported.

The investigation follows concerns among regulators that some fintechs are manipulating the rules in order to provide high-speed payments to customers.

This makes it difficult for Visa to check for money laundering and fraud, industry insiders told the publication.

According to the report, the probe, which started in June, was mentioned in the company’s most recent regulatory filing. The company, which did not reveal the scope of the investigation, said it has been cooperating with the probe.

Electronic payments firmEuronetfiled a lawsuit against Visa last year.

Euronet alleged that Visa’s certain rules related to ATM access fees in Poland, the Czech Republic and Greece are against the competition laws. It is reportedly seeking damages, costs, and injunctive relief to stop Visa and Mastercard from enforcing the rules.

Australia-based electronic money company iSignthisalso alleged Visa of limiting data access for smaller fintechs, the report said. The company’s licence with Visa ended last month.

A spokesperson for Visa was quoted as saying: “We are working with a wide variety of fintechs and start-ups to provide them open access to our global network.

“We welcome new solutions and new ways for people to make electronic payments and for merchants to accept them, subject always to delivering the security and convenience that our customers expect from Visa.”

Last week, Visa and digital wallet firm Vipps announced a strategic partnership to accelerate mobile payments in Europe.