West Bromwich Building Society is celebrating after a posting a set of "outstanding" half year results.
However, the society said the slowdown in the housing market meant its full year figures may not repeat its previous record levels.
The business yesterday revealed its results for the half year ending September 30.
It highlighted growth of eight per cent to total assets of £6.4 billion, with mortgage assets up nine per cent to £5.1 billion.
Gross lending was up eight per cent to £1 billion and its group solvency ratio stood at 15.3 per cent.
Net savings balances were up by £240 million; group pre-tax profit was up by three per cent, from the prior period, to £20.9 million, and group management expenses ratio was 0.74 per cent (prior period 0.85 per cent).
Group arrears (2.5 per cent or more) of 0.57 per cent were maintained at "historic low levels."
The society said these were "outstanding results by any measure."
The core society was performing well and group profit also benefited from the "particularly strong results generated by subsidiaries."
The results demonstrated that the group continued to make good progress "in all areas of the business" and had built a position of substantial capital strength.
The results were prepared for the first time under International Financial Reporting Standards, the society said.
The inclusion of investment property revaluation gains had a material impact on the reported profit figure but, otherwise, the impact of IFRS had a lesser effect than for other lenders.
This was because the group had historically adopted accounting policies that spread mortgage acquisition costs, consistent with IFRS, a policy that was new for many other companies.
The society said: "Comparison of the results reported with the prior period is complex as not all standards require previous periods to be restated.
"However, had the accounting changes been fully applied to the previous periods, the reported profit before tax would be around ten per cent higher than the equivalent period in the previous year."
While the West Brom continued to make good progress with underlying profitability remaining strong, the new accounting approach was likely to cause fluctuations in reported profitability from year-to-year.
In particular, that applied to investment property revaluation gains.
The society said: "Although overall the interim results were broadly comparable with last year and we expect further progress in our underlying businesses in the second half, the slowdown in the housing market could mean that the contribution of our investment properties might not be as great as last year.
As a consequence, the full year results might not repeat the previous year's record performance."
Chief executive Andrew Messenger said that despite fierce competition, increasing regulation and uncertainty over markets and business conditions, "we have performed well."
He added: "Our subsidiaries and core member business are performing in line with expectations and we are building a strong, sustainable mutual building society."
He said future focus would be on delivering profitable growth, increasing financial strength and offering exceptional value, service and advice. ..SUPL: