Genworth Mortgage Insurance Australia has renewed its lenders mortgage insurance contract with Commonwealth Bank. The contract is critical for Genworth, as it accounts for 53 per cent of the insurers gross written premium.The contract has been renewed for three years. Genworth chief executive Georgette Nicholas said in a statement that the new contract provides the opportunity to expand the relationship with CBA through new product and service offerings."The new CBA contract is on terms that meet our pricing return on equity profile and risk appetite," Nicholas said.The company also announced that Nicholas would leave the company on December 31.Despite the fact that she announced her resignation in May, the company has not yet found a new CEO. Non-executive director Duncan West will serve as acting CEO.In a September quarter earnings update, the company reported a 24.4 per cent increase in gross written premium, compared with the prior corresponding period, and a 28 per cent increase in net profit.Nicholas said the increase in premium was driven by a higher volume of high loan-to-valuation lending. It was the best quarter for gross written premium in four years.The number of paid claims rose from 320 in the September quarter last year to 361 in the latest quarter.