The nine largest banks and building societies in Great Britain and Northern Ireland, based on the volume of personal and business current accounts.

They are as follows: AIB Group (UK) plc trading as First Trust Bank in Northern Ireland, Bank of Ireland (UK) plc, Barclays Bank plc, HSBC Group, Lloyds Banking Group plc, Nationwide Building Society, Northern Bank Limited, trading as Danske Bank, NatWest Group plc, Santander UK plc (in Great Britain and Northern Ireland).