Investor demand for mortgage-backed securities remains strong, despite the high volume of issuance so far this year. On Friday, Suncorp Bank upsized its latest RMBS issues and priced the top tranche at less than 100 basis points over the swap rate.Suncorp upsized Apollo Series 2013-1 from the A$750 million offered at its launch to $1.15 billion.Pricing on the $1.06 billion A tranche, which has a weighted average life of 3.4 years, is 95 bps over the one-month bank bill swap rate.Pricing on the $63.2 million AB tranche, which has a weighted average life of 5.9 years, is 170 bps over swap.Pricing on the $11.5 million B1 tranche, which has a weighted average life of 5.9 years, is 280 basis points over swap.Pricing on the $5.7 million B2 tranche, which has a weighted average life of 5.9 years, is 325 bps over swap.Suncorp Bank's chief executive, David Foster, said in a statement that 22 institutional investors and eight bank investors participated in the transaction. There were investors from Hong Kong, the United Kingdom, Japan and New Zealand.Deutsche Bank arranged the deal. Deutsche, ANZ, Macquarie Bank and NAB were joint lead managers.This year's RMBS issuers include Commonwealth Bank, which has issued $2.5 billion, Westpac ($2.1 billion), ING Direct ($1 billion), Bendigo and Adelaide Bank ($850 million), Resimac $750 million), Columbus Capital ($500 million), Liberty Financial ($500 million), Pepper Australia ($350 million) and AFG ($275 million).