Standard & Poor's yesterday announced a lowering in the credit rating for the banking business of Suncorp, which the credit rating reduced to A from A+.The long-term rating of the Suncorp insurance subsidiaries remains at A+.S&P said in the ratings announcement that it "reduced the ratings uplift embedded in the rating of the bank by one notch" and due to Suncorp's changed strategy toward the bank, which is informally for sale.Suncorp knocked back an offer from ANZ to buy the bank in October, with the sale process overtaken by the introduction of the Australian government guarantee.The divergent S&P ratings may reinforce Suncorp's need to borrow in wholesale markets using the guarantee.