That statistic is misleading. Much of that change is the result of mergers. Just take a look at the list from 1955: http://archive.fortune.com/magazines/fortune

That statistic is misleading. Much of that change is the result of mergers. Just take a look at the list from 1955: http://archive.fortune.com/magazines/fortune/fortune500_archive/full/1955/ http://archive.fortune.com/magazines/fortune/fortune500_arch... . Just looking through the top 25, the vast majority still exist in some form in the Fortune 500 today. Only a few have flat out gone out of business (e.g. Bethlehem Steel) or been booted from the Fortune 500 because the overall industry shrank (e.g. pretty much the rest of the steel companies). Being in technology, which changes so rapidly, it's easy to think that "small companies overtaking big companies" is the norm, but if you look at more "static" industries, the leaders back in 1955 (e.g. Exxon Mobile, Kraft, Proctor and Gamble) are still the leaders today.