AutoZone is adding another $750 million to its ongoing share buyback program, the Memphis-based car parts retailer announced after market close on Wednesday, Oct. 7. The company said that including the new amount authorized by its board, AutoZone has since 1998 authorized share buybacks worth $16.4 billion. AutoZone chief financial officer Bill Giles said in a release about the news that the company's "continued strong financial performance" allows the company to buy back its stock while maintaining its investment grade rating.