Mortgage insurers earned a total of A$999 million of premium income in the year to June last year and incurred claims of just $177 million.The segment is of increasing interest, not just to the banks and other lenders that buy this insurance (in a highly concentrated market) but also to investors, who will soon be asked to buy a stake of up to 40 per cent in Genworth Financial Australia, one of the two largest providers in this category of insurance.These figures on lenders' mortgage insurance are included in a report on the direct general insurance market released by the Australian Prudential Regulation Authority yesterday. No other class of general insurance comes close to the margin that mortgage insurers earn.Domestic motor vehicle is the biggest class, with $6.6 billion of premiums in 2010/11 and $6 billion of claims incurred.Home-owners' insurance generated $5.4 billion of premiums and $4.5 billion of claims.Fire and industrial special risks' insurance generated premium income of $3.3 billion and incurred claims of the same amount.Compulsory third-party motor vehicle insurance generated premiums of $2.7 billion and incurred claims of $2.4 billion.Meanwhile, Genworth announced the appointment of Richard Grellman as non-executive chairman of Genworth Australia Taiwan.Genworth's US parent announced last year that the Australian business would make a minority-share initial public offering and list on the Australian Securities Exchange this year.Grellman, who has plenty of experience as a listed company director, will help guide the local board through this process.He was a director of AMP Ltd between 2000 and 2011, chairman of medical services company Cryosite Ltd between 2002 and 2008, and a director of Centennial Coal between 2008 and 2010.