British Airways was hit Monday with the largest penalty to date under the European Union’s General Data Protection Regulation, a £183.39m (U.S. $230 million) fine stemming from the compromised data of nearly 500,000 customers.

The nearly quarter-billion-dollar penalty, announced by the U.K.’s Information Commissioner’s Office (ICO), amounts to nearly 1.5 percent of British Airways’ annual revenue for the financial year that ended Dec. 31, 2017.