Suncorp yesterday sold $850 million in three year debt, possibly the financier's first sale of debt through the public bond market since the liquidity crunch took hold nine months ago.The bank sold $600 million in fixed-rate debt and $250 million in floating rate debt. The bank struck a margin of 130 basis points over the three-year swap rate on the fixed term debt and the same margin over the three-month swap rate on the floating rate debt.The margin on Suncorp's debt compares favourably with that of AMP, which sold $250 million in fixed and floating rate debt two weeks ago. Suncorp has a long term credit rating of A+ from Standard & Poor's while AMP has a rating of A.