Fitch Ratings and S&P Global Ratings have assigned expected ratings to Bank of Queensland's first prime residential mortgage backed securities issue for the 2017 calendar year. The two highest rated notes in the Series 2017-1 REDS Trust, the Class A1 and Class A2 notes, total A$460 million and $18.75 million, respectively. These have both been provisionally rated as AAA(EXP)sf by Fitch and AAA (sf) by S&P. The next three tranches, comprising $8.50 million Class AB notes; $7.50 million Class B notes; and $4.70 million Class C notes, were assigned provisional ratings of AAA (sf) AA (sf) and A (sf), respectively, by S&P. The $0.55 million Class D notes were not rated by S&P. The AB, B, C and D notes have not been rated by Fitch.According to a Fitch pre-sale media release, the total collateral pool consisted of 2,157 loans, totalling A$500 million at the 18 December 2016 cut-off date. The average current loan size is $291,375. Investment loans represent 38 per cent of the pool by balance, interest-only loans represent 22.5 per cent and fixed-rate loans 25.4 per cent."The final loan pool will be finalised prior to the closing date and adjusted to match the final liability balance," Fitch said.The credit enhancement provided by the class A2, AB, B, C, and D notes is sufficient to leave the A1 notes independent of any credit provided by lenders' mortgage insurance. Similarly, the rating of the class A2 notes is based upon the credit support provided by the subordinated notes and is independent of LMI credit.