FirstMac is returning to the mortgage-backed securities market with the planned sale of A$300 million in bonds that are supported by full-doc loans.In August, the Brisbane-based mortgage manager sold $80 million in RMBS backed by low-doc loans, in a deal priced at up to 375 basis points over the one-month bank bill swap rate.Fitch Ratings wrote in a pre-sale report on the latest RMBS that "FirstMac has not provided income information for any of the loans in the pool and there are no low documentation loans within the pool."FirstMac also said the loan pool was "100 per cent full doc."As with recent FirstMac RMBS issues, one investor in the securities is likely to be High Livez, a retail managed fund established by FirstMac last year to invest in securities issued by wholesale trusts managed by the financier.High Livez reported a distribution of 7.63 per cent and a "total return" of 7.8 per cent for the fund as at the end of September, with 80 per cent of funds invested in asset-backed securities.