Nationwide Building Society

Nationwide Building Society is a British mutual financial institution and the largest building society in the world. It has its headquarters in Swindon, with an office in Threadneedle Street, London, and with administration centres based in Bournemouth, Northampton and Dunfermline.

Made up of over a hundred mergers — most notably its merger with Anglia Building Society in 1987 and Portman Building Society in 2007 — Nationwide is now the second largest provider of household savings and mortgages in the UK. It also has a 6.8% market share of current accounts and has had the highest customer satisfaction rating of any UK high street financial service provider for over three years - at 94%.

In 2013, Nationwide had assets of around £193.3 billion compared to £325 billion for the entire building society sector, making it larger than the remaining 44 British building societies combined.

It is a member of the Building Societies Association, the Council of Mortgage Lenders and Co-operatives UK.