Ulster Bank is a large retail bank, and one of the traditional Big Four Irish clearing banks. The Ulster Bank Group was subdivided into two separate legal entities: National Westminster Bank Plc, trading as Ulster Bank ; and, until April 2023, Ulster Bank Ireland DAC. Prior to the closure of Ulster Bank in the Republic of Ireland in April 2023, the headquarters of Ulster Bank in the Republic of Ireland were located on George's Quay, Dublin, whilst the headquarters of Ulster Bank Northern Ireland are in Donegall Square East, Belfast, and it maintains a large sector of the financial services in both the UK and the Republic of Ireland.

National Westminster Bank, trading as NatWest, is a major retail and commercial bank in the United Kingdom based in London, England. It was established in 1968 by the merger of National Provincial Bank and Westminster Bank. In 2000, it became part of The Royal Bank of Scotland Group, which was re-named NatWest Group in 2020. Following ringfencing of the group's core domestic business, the bank became a direct subsidiary of NatWest Holdings; NatWest Markets comprises the non-ringfenced investment banking arm. The British government currently owns 35% of NatWest Group after spending £45 billion bailing out the lender in 2008; the proportion at one point was 54.7%. NatWest International is a trading name of RBS International, which also sits outside the ringfence.