The Fortune 500 is an annual list compiled and published by Fortune magazine that ranks the top 500 U.S. closely held and public corporations as ranked by their gross revenue after adjustments made by Fortune to exclude the impact of excise taxes companies collect.[1] The list includes publicly and privately-held companies for which revenues are publicly available. The first Fortune 500 list was published in 1955.

Wal-Mart was the largest company on the list in 2007 and 2008. ExxonMobil was in second place[2] in 2007 and 2008, but overtook Wal-Mart in 2009.[3] Wal-Mart once again regained the top spot in 2010. One should note that the revenue and profit numbers are for the year previous to the named year: therefore the 2010 list ranks companies by 2009 revenues.

Although the Fortune 500 list is the most familiar one, similar gross revenue lists of the top firms range from the highest ranking Fortune 100 including the top one hundred to the broader ranking Fortune 1000 that includes the top thousand firms. While the membership on the smaller lists are somewhat stable, the ranking on the lists may change over time, depending upon revenues and often, because of mergers among firms already listed.

The original Fortune 500 was restricted to companies whose revenues were derived from manufacturing, mining, or energy exploration. At the same time, Fortune published companion "Fortune 50" lists of the 50 largest commercial banks (ranked by assets), utilities (ranked by assets), life insurance companies (ranked by assets), retailers (ranked by gross revenues) and transportation companies (ranked by revenues). These have been consolidated into one single list, so the Fortune 500 as it exists today includes companies that in previous years would have been on one of the "Fortune 50" lists.