Investors in the giant US mortgage debt market have been growing more confident that they will be repaid, despite the serious problems experienced by Fannie Mae and Freddie Mac.

Risk premiums for mortgage bonds fell late last week after days of volatile trading. Rates on 30-year fixed mortgages dropped to 6.13 per cent from 6.25 per cent last week, according to BankRate.com. Mortgage rates, however, are up from under 6 per cent in May.