The number of buy-to-let mortgage products available has more than doubled over the last 12 months, according to the latest Complex Buy-to-Let Index from Mortgages For Business.

In the first quarter of 2010, an average of 142 products were available to buy-to-let investors. This figure has more than doubled to an average of 298 products in Q1 2011. Mortgages For Business says this rise is due in part to the entrance (or re-entrance) of four mortgage lenders to the market but can be attributed mainly to lender response to high demand from the investor market and an easing of lending criteria which has allowed for more diverse product ranges.

Average LTVs for ‘vanilla’ buy-to-let transactions are now at 66%, three percentage points up (63%) from the end of 2010 and six percentage points up (66%) from the end of 2009. There has also been an easing of criteria for Houses in Multiple Occupation (HMO) transactions. Average LTVs for these mortgages are now 63% compared to 61% at the end of 2010.

Complex buy-to-let transactions provide the highest yields for investors and yield growth has been strong over the first quarter of 2011. HMO transactions now provide an average yield of 9.3% compared to 8.7% at the end of 2010 and Multi-unit Freehold Blocks (MUFB) now yield 7.4% compared to 5.3% in 2010.

David Whittaker, managing director at Mortgages for Business, said: “As the owner-occupier market continues its slow ambling advance through no-mans land the private rental sector is flourishing. Unprecedented demand from renters is encouraging professional landlords and investors to grow their portfolios and this demand has been met to some degree by lenders expanding their buy-to-let product ranges