Leading position in the retail auto parts aftermarket; Generates healthy free operating cash flow; and Good operating margins compared with industry peers. Operates in the highly competitive auto parts industry; Flat-to-slightly negative same-store sales in recent years; and History of aggressive share repurchases. The ratings on Memphis, Tenn.-based AutoZone Inc. reflect the company's leading position in the generally stable but highly competitive retail automobile parts aftermarket, consistent operating performance, and strong profitability measures. These strengths are somewhat tempered by management's historically aggressive share repurchase activity and expectations for continued flat-to-negative same-store sales performance resulting from difficult macroeconomic conditions. AutoZone is the largest retailer of automotive parts in the U.S., with about 4,122 stores domestically and in Puerto Rico, as well