CHICAGO (Standard&Poor's) April 17, 2012--Standard&Poor's Ratings Services said today that it assigned its preliminary 'BBB' and 'BBB-' senior unsecured and subordinated debt ratings, respectively, to Memphis, Tenn.-based AutoZone Inc.'s Rule 415 shelf registration statement filed April 17, 2012. The company plans to immediately draw down $500 million ten-year senior unsecured notes from the shelf. We rate the proposed issuance 'BBB'. We also withdrew our preliminary 'BBB' and 'BBB-' senior and subordinated debt ratings from AutoZone's shelf registration statement dated July 29, 2008, which has expired. All of the company's remaining ratings, including the 'BBB' corporate credit rating, are unchanged. Our rating outlook on the company is stable. We expect AutoZone to use net proceeds from the