Famous Companies Dropped From the S&P 500:
The S&P 500 is a fluid index, which means that certain components are removed and replaced from time to time. For example, companies may be removed if they are in some type of financial distress. Replacing components of the index is fairly common. In 2015, 24 changes were made to the S&P 500's composition.
Well-known name gets dropped from the index; companies that were once industry leaders may fall on hard economic times or go bankrupt. There are several reasons why a company may get removed from the index, as can be seen by looking at the Index's history of dropped companies. Same is true for other indices like NASDAQ.
dozu888: you go study up.
https://www.investopedia.com/articles/investing/022416/5-famous-companies-dropped-sp-500.asp