Nationwide is the world's largest building society as well as one of the largest savings providers and a top-three provider o ... f mortgages in the UK. It is also a major provider of current accounts, credit cards, ISAs and personal loans. Nationwide has around 15 million customers. Customers can manage their finances in a branch, via the mobile app, on the telephone, internet and post. The Society has around 17,000 employees. Nationwide's head office is in Swindon with administration centres based in Northampton, Bournemouth and Dunfermline. The Society also has a number of call centres across the UK. read more