Wal-Mart rules the Fortune 500 for the second year in a row -- and the eighth time this decade -- beating Exxon Mobil decisively in the battle to be crowned America's largest company.
But things haven't been easy: Sales at its U.S. stores have dropped for seven straight quarters, despite gains in worldwide revenues and profits.
To fight back, CEO Michael Duke is restocking shelves with lower-priced products dropped by his predecessor, Lee Scott. He's also jumping on the anti-obesity bandwagon: Thousands of packaged food items are being reconfigured to cut their salt and sugar content. --Peter Newcomb, contributor