Westpac is making the first securitisation deal by a major bank in 2011 - and its first since December 2009 - with a small A$435 million RMBS deal that will not be reliant on mortgage insurance.The pool backing the deal is more than two years seasoned and its weighted average loan-to-value ratio is 64.4 per cent. It is a closed pool with no pre-funding and substitution taking place during the life of the deal. The securities consist of $400 million of Class A notes and $15 million of Class B notes, which are both top rated, and $20 million of Class C notes that are not rated.  A small proportion, of around 4.1 per cent, of the pool is insured, which is for loans with loan-to -valuation ratios in excess of 80 per cent.Westpac's last foray into the residential mortgage-backed securities market was in December 2009, when it raised $2 billion with the top-rated tranche issued at a spread of 130 basis points over one-month swap.