The West Bromwich Building Society has announced record financial results for the tenth year running.
But the 158 year-old mutual faces a period of uncertainty over the economy and the housing market, chief executive Stephen Karle has warned.
Figures for the 12 months to March 31 show that the country's ninth biggest building society made a pretax profit of £44.1 million, a rise of 14.5 per cent compared with the £38.5 million surplus the previous year.
Total assets grew by 15.4 per cent to a record £8.3 billion and mortgage assets under management rose by 18 per cent to £6.7 billion, another record.
Gross lending reached an all-time high of £2.5 billion, a rise of 15.8 per cent and the society's net savings balances grew by £550 million to £4.5 billion.
Subsidiary businesses, which include residential property investment, commercial lending and a mortgage broker franchise, contributed pretax profits of £22.8 million, an increase of 25 per cent.
The West Brom, which strengthened its balance sheet last year through the securitisation of £600 million of loans, returned the highest level of benefits ever seen to members - £34.1 million - in the form of improved investment rates and lower mortgage rates.
Efficiency gains last year saw the management expense ratio cut for the seventh year in a row, this time from 0.69 per cent of assets to 0.66 per cent.
The solvency ratio at the year end was 12.77 per cent, a level well ahead of regulatory requirements.
And despite the growth in the mortgage book and a deteriorating debt environment, only 0.5 per cent of the West Brom's borrowers are more than 2.5 per cent in arrears, a figure approximately half the average level for the rest of the sector.
Mr Karle, who presented his first set of annual figures since taking over as chief executive from the long-serving Andrew Messenger, 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 £8 billion, making us one of the fastest growing building societies in the whole of the UK.
"Looking ahead, we face a year of greater uncertainty in the economy and the housing market.
"Despite this, we are confident that the sound, broadly-based strategy of the group, supported by investment in new and innovative products, technology and our people, will continue to produce satisfactory results and enable the society to provide exceptional benefits to our members."
Consolidation in the building society sector is picking up pace with the merger of market leader Nationwide with the third-ranked Portman.
Mr Karle said: "We do not need to merge with other societies in order to continue our record of success.
"The society is ready to examine merger and other business alliance opportunities but only if we believe it will deliver increased long term benefits to our members."