Fidor Bank U.K., a digital challenger bank from Germany's Fidor Group, said it will close its U.K. operations by Sept. 15, citing uncertainty related to Brexit. 

Fidor Bank U.K. posted an announcement on its website and sent notices to account holders regarding the shutdown, asking customers to withdraw all funds by the 15th, but giving them login access until Sept. 30. Fidor still operates a challenger bank in Germany called Fidor Bank DE. 

The bank said that debit Mastercard will automatically be deactivated as of Sept. 15th. 

French banking entitity Group BPCE acquired Fidor in 2016.