UPDATE 1-AutoZone adds $500 mln for share buybacks

* CFO says financial health allows repurchase

DETROIT, June 17 (Reuters) - AutoZone Inc (AZO.N), the leading U.S. auto parts retailer, said on Wednesday its board had authorized another $500 million to buy back common stock.

Shares in the Memphis-based company have gained almost 12 percent since the start of the year as the U.S. recession has prompted more consumers to drive cars longer and shop for better deals on replacement parts.

"AutoZone's strong financial health has allowed us to continue to repurchase our stock while operating within our targeted leverage metric," said AutoZone Chief Financial Officer Bill Giles said in a statement.

In late May, AutoZone posted a 9-percent gain in profit that topped analyst estimates.

Billionaire investor Edward Lampert and his ESL Investments owns about 43 percent of AutoZone. Lampert is also the largest shareholder in AutoNation (AN.N), the largest U.S. auto dealership chain.

The deep U.S. recession has thrown the nation's auto industry into turmoil, forcing both Chrysler (FIA.MI) and General Motors Corp GMGMQ.PK into bankruptcy filings financed by the Obama administration.

Both GM and Chrysler are closing U.S. dealerships and their affiliated repair shops as they restructure. (Reporting by Kevin Krolicki; Editing by Tim Dobbyn)