The cost of issuing residential mortgage-backed securities over the past couple of weeks has been as low as 85 basis points over the bank bill swap rate for big banks, and as high as 105 bps over swap for mutual banks. P&N Bank will pay 105 bps over the one-month bank bill swap rate on the A$276 million A tranche of its latest RMBS issue. The tranche has a weighted average life of 2.9 years.The issue, the Pinnacle Series Trust 2013-T1, is P&N's first RMBS transaction since 2010 and only its second RMBS issue.At the end of September, Westpac priced the $2.1 billion A tranche of its latest RMBS issue, with a weighted average life of three years, at 85 bps over swap.And, last week, ME Bank priced the $1.1 billion A1 tranche of its issue, with a weighted average life of 2.8 years, at 95 bps over swap.P&N Bank raised a total of $300 million. Pricing on the $16.5 million AB tranche, which has a weighted average life of 4.8 years, was 215 bps over swap.Pricing on the $6 million B1 tranche, which has a weighted average life of 4.8 years, was 320 bps over swap.And pricing on the $1.5 million B2 tranche, which has a weighted average life of 4.8 years, was 360 bps over swap.P&N said 13 investors participated in the deal.