Question:  Egg Banking is a former name of the building society that had headquarters in what city?
Context: The Cambridge Building Society is a UK mutual building society based in Cambridge, Cambridgeshire, England.  It is the 14th largest in the United Kingdom based on total assets of £1,128 million at 31 December 2015.  It is a member of the Building Societies Association.  The Society was formed in 1850 as the Cambridgeshire Permanent Benefit Building Society, adopting its current name in 1945.  There is no connection between this Society and the Cambridge Foresters’ Benefit Building Society which was dissolved in 1960 or the Cambridge Peers Economic Building Society which was dissolved in 1972. Kent Reliance, formerly known as Kent Reliance Building Society and also known as KRBS, is a banking services provider based in Kent, England.  Until 31 January 2011 KRBS stood for Kent Reliance Building Society, which was created in 1986 and incorporated Chatham Reliance (established 1898), Dover District (established 1861), Herne Bay (established 1888) and Kent and Canterbury (established 1847).  On 1 February 2011, Kent Reliance Building Society transferred its business to a new bank, OneSavings Bank plc (which trades as Kent Reliance). The Yorkshire Building Society is the third largest building society in the UK, with its headquarters in Bradford, West Yorkshire, England.  It is a member of the Building Societies Association. Egg is a former British internet bank headquartered in Derby, that is now a trading name of Yorkshire Building Society.  Egg was born out of the UK banking arm of Prudential plc, Prudential Banking plc, which was established in 1996, and the Egg brand was launched in 1998.  The first online credit card was launched in 1999. The Chesham Building Society was a building society based in the market town of Chesham in Buckinghamshire, England which merged with the Skipton Building Society in June 2010.  Prior to the merger it was the 37th largest building society in the United Kingdom based on its total assets of £231 million.  It was a member of the Building Societies Association. The Dunfermline Building Society was a building society and later a trading division of Nationwide Building Society, based in Dunfermline, Fife, Scotland.  Before its 2009 merger with Nationwide, it was the largest building society in Scotland and the 12th largest in the United Kingdom based on total assets of £3.3 billion at 31 December 2007.  It was a member of the Building Societies Association. Derbyshire Building Society (previously trading as The Derbyshire) was a UK building society based in Duffield, Derbyshire in the East Midlands of England.  It was the 9th largest building society in the United Kingdom based on total assets of £7.1 billion at 31 December 2007, until it was acquired by Nationwide Building Society (Nationwide) on 1 December 2008.  It operated as a trading division of the society, with 50 branches, until it was fully integrated into its parent in November 2014. The Portman Building Society was a mutual building society in the United Kingdom, providing mortgages and savings accounts to consumers and offering loans to commercial enterprises.  Its head office was in Bournemouth and its administration centre in Wolverhampton.  Portman merged with the Nationwide Building Society in August 2007, at which time it was the third largest building society in the UK and the largest regional building society in the south of England, with 154 branches and assets exceeding £15 billion. The Scottish Building Society is a building society based in Edinburgh, Scotland.  It is the oldest building society in the world, the only building society based in Scotland and the 42nd largest in the United Kingdom based on total assets of £377.6 million at 31 January 2015.  It is a member of the Building Societies Association. A building society is a financial institution owned by its members as a mutual organization.  Building societies offer banking and related financial services, especially savings and mortgage lending.  Building societies exist in the United Kingdom (UK), and used to exist in Ireland and several Commonwealth countries.  They are similar to credit unions in organisation, though few enforce a common bond.  However, rather than promoting thrift and offering unsecured and business loans, the purpose of a building society is to provide home mortgages to members.  Borrowers and depositors are society members, setting policy and appointing directors on a one-member, one-vote basis.  Building societies often provide other retail banking services, such as current accounts, credit cards and personal loans.  The term "building society" first arose in the 18th century in Great Britain from cooperative savings groups.
Answer: Bradford