Wal-Mart retakes the No. 1 slot on the Fortune 500 this year. See where America's largest corporations rank, and why. (more) Exxon Mobil was the most profitable company last year by far, raking in $39.5 billion in earnings. Who else made the top 20? (more) These female execs are heading up top companies like Avon, eBay and ADM. (more) | |