Research from Commonwealth Bank has clarified the extent of the decline in spreads on high-end corporate loans over the last year, one of the factors containing margins for big banks.Generic corporate pricing for BBB-rated (or equivalent) credit for terms of three years or more fell by 30 basis points to around 130 bps over the year to December 2013, CBA said in an annual research report on the debt market.The margin decrease was even greater for the five-year tenors, CBA said, with generic pricing down by around 40 bps to around 160 bps. The bank said "this may be predominantly attributable to the lower loan volumes in 2013 compared to the last two years, coupled with an abundance of liquidity from lenders, particularly for investment grade borrowers."Taking into account the fall in bank bill swap rates CBA said "this effectively translated into a double win for borrowers and most BBB-rated (or equivalent) borrowers were able to borrow funds in the loan market for a tenor of three years at an all-in cost of borrowings between four per cent and five per cent."The bank estimated loan market volume for 2013 at US$95 billion, down two per cent on the 2012 volume.CBA said while Australian loan market volume by dollar amount was down on 2012, the deal count was significantly higher: 192 transactions were closed in 2013, compared to 148 in 2012. Australian banks accounted for 49 per cent of commitments in the syndicated loan market in 2013, CBA said, down from 51 per cent in 2012. CXBA said this was "no surprise, as some international banks that repatriated funds during the GFC returned to Australia."International banks stepped up their level of commitment as the syndicated loan market saw limited new transactions," with banks from Japan funding approximately 10 per cent of the syndicated loan market.