This new contract, which takes effect from January 2010, extends Connells and the Nationwide group partnership into its 20th year.
Nationwide now accounts for around 1 in every 10 mortgages sold in the UK. It's aim is to have the size, scale and reach of the retail banks combined with traditional building society values of transparency and long term good value for their membership.
Roland McCormack, Connells Asset Management Managing Director, said: "Nationwide Building Society remains at the forefront of the market and we are delighted to have been appointed in this critical business area. We relish the prospect of adding value to the Society's customer service proposition in this new economic era."