The London-based firm uncovered the issue through internal quality controls and self-reported the findings to U.K. authorities. While the company has already issued corrected statements and pledged to handle all potential financial liabilities at its own expense, the incident highlights a growing series of regulatory hurdles for the business. Wise confirmed that the technical flaw has been patched, ensuring no further risk to its user base.

This tax-related complication follows a turbulent period for the company. Belgian prosecutors initiated a money-laundering probe in June concerning transactions exceeding 500 million euros, and in July, the U.S. Office of the Comptroller of the Currency denied Wise a national trust bank charter. The regulator pointed to specific deficiencies in the firm's anti-money laundering and terrorism financing programs, casting a shadow over the company's expansion efforts following its move to list on the New York Stock Exchange.