Coventry Building Society has seen its total assets soar by nearly half a billion pounds since the start of the year.

Interim figures from the country's fifth largest mutual mortgage lender and savings provider show that the business grew to £11.571 billion in value in the six months to June 30. That's an increase of £481.2 million, or 4.3 per cent, since the start of the year and a rise of more than £1 billion, or ten per cent, over the same period last year.

The Coventry, which recently said farewell to longserving chief executive Martin Ritchley, said growth in both savings and mortgage balances had delivered a strong financial performance in the first half of the year.

Yesterday's figures showed that mortgage and other loans increased by £385 million to a record £9.4 billion while savings balances put on five per cent to £7.8 billion.

Pretax profits rose by 13 per cent to £29 million.

The Coventry's net interest margin, the difference between interest paid to savers and interest paid by borrowers and a key indicator of the value offered to members, was reduced to 0.85 per cent from 0.93 per cent this time last year.

Management expenses as a ratio of assets was cut to 0.55 per cent from 0.59 per cent.

New chief executive David Stewart, the society's former operations director who succeeded Mr Ritchley last month, said: "As a building society, our aim is to provide good value mortgage and savings products for the benefit of our members.

"I am therefore very pleased to report further growth in both mortgage and savings balances, both of which have risen to record levels.

"We have been particularly keen to help first time buyers in what is a difficult market for them and it is pleasing that these efforts have been recognised in the form of several independent awards."

The Coventry is winning a reputation for innovation in the savings market and recently added the Coventry First current and savings account to the portfolio.

"With no dividends to pay to outside shareholders, we have again been able to narrow our interest margin, now 0.85 per cent of average assets, for the benefit of our saving and borrowing members," Mr Stewart said. "We also continue to improve our efficiency and I am pleased to report a further reduction in our management expenses to average assets ratio to 0.55 per cent."