International ratings service Standard & Poor's (S&P) has raised its corporate credit rating on pizza delivery company Domino's to double-'B'-minus from single-'B'-plus based on the company's improved operating performance and credit protection measures. The outlook is stable. S&P said the ratings on Domino's reflect its participation in the highly competitive pizza industry, a narrow product focus, and a significant debt burden of US$640m outstanding as of 24 March 2002.