Standard & Poor's Corp. said Tuesday it has raised its corporate credit ratings for major department store operators Isetan Co. and Mitsukoshi Ltd.

The credit rating agency also said further upgrades were possible if the earnings environment improves further.

S&P raised its corporate credit rating on Isetan to BBB-minus-pi from BB-plus-pi "based on the company's improving profitability and cash flow protection stemming from its enhanced merchandising capabilities and steady debt reduction."