The growth took West Brom’s assets to £8.3bn, while its mortgage assets also increased, up 18% to £6.7bn.
The Society said that despite mortgage balances having grown significantly, residential and commercial mortgage arrears were down, with only 0.50% of cases more than 2.5% in arrears, which it said was half the average level seen across the rest of the industry.
Commenting on the results, Stephen Karle, chief executive of West Bromwich Building Society, said: “The Society has, for the 10th consecutive year, produced record financial results. Over this decade we have experienced a remarkable period of success with assets now standing at more than £8bn, making us one of the fastest growing building societies in the whole of the UK. A decade of success built upon a clear vision and strategy, a commitment to member value and service and, most of all, the dedication, hard work and flair of our tremendously talented staff.”