Coventry Building Society posted record results as its conservative business model enabled it to thrive despite the credit crunch.
The UK's third largest building society reported a 40% jump in underlying pre-tax profits to £46.5 million for the six months to the end of June.
The group attributed its success to its "simple business model", which it said had enabled it to weather the events of the past three years.
It said its policy of funding all of its mortgage lending through savers' deposits had enabled it to remain "open for business" during the credit crunch, with its mortgage book increasing by 6% during the first half of the year - broadly in line with its performance over the past 10 years.
Overall, net mortgage lending totalled £751 million during the first half of the year.
The increase in lending led to the group achieving a record net mortgage market share of 31%.
However, the figure needs to be seen in the context of the fact that many banks and building societies are not actively lending, giving them a negative net lending figure.
The group's growth in mortgage lending was matched by an even bigger jump in savings levels, with deposits increasing by £1.7 billion or 13% during the six months, as the society focused on cushioning its members from the full impact of the record low base rate.
The society said that even though the cost of attracting savings had increased significantly in relation to the base rate, limited competition in the mortgage market meant it was able to recoup this through the higher margins it charged on lending.