Belgian prosecutors announced Monday that they were in the advanced stages of an investigation into money transfer giant Wise, on suspicions that criminals used its accounts for money laundering, sending the shares of the company sharply down.

The Brussels prosecutors' office said it launched the probe last year as the British firm's name kept popping up in hundreds of requests for assistance from investigating authorities in other countries.

"The investigation is now at an advanced stage and nearing its conclusion," a spokesperson for the prosecutors' office told Agence France-Presse (AFP), confirming information first reported by the European Investigative Collaborations (EIC) network.

"The findings primarily concern the use of Wise accounts for criminal purposes, with indications of non-compliance with anti-money laundering legislation, particularly due to a failure to identify customers and their activities."

Detectives were probing whether criminal groups used Wise services to launder the proceeds of illicit activities, including fraud, corruption, and drug trafficking.

The probe focuses on Wise Europe, the firm's Belgium-headquartered European subsidiary, which said it was working with prosecutors to respond to queries about its business.

Such requests for information "are a normal part of operations and are not, in themselves, indicative of non-compliance with anti-money laundering requirements or of any wrongdoing," the company said in a statement.

"No specific findings have been shared with us to date," the company, which has more than 19 million active customers worldwide and processes approximately 4.7 million transactions per day, added.

Wise says it processed more than 243 billion dollars in cross-border transactions in the financial year 2026.

By midday, its share price on the London Stock Exchange had fallen by nearly 15%.