Companies get added to and deleted from the S&P 500 (SNPINDEX:^GSPC) all the time. But can it be predicted? In the following video, Motley Fool contributor John Maxfield discusses the two main reasons companies get booted from the index and what impact being added has on the short- and long-term performance of stocks.

Erin Miller, John Maxfield, and The Motley Fool have no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.