Of course, changes in the economy, especially those significant enough to be reflected in the S&P 500, do not happen in a vacuum. The circumstances of the world at large help give additional context to why certain industries might thrive or struggle at given points in time. In order to demonstrate this, we’ve put together the above timelines to provide that context to the data we collected.

Each graphic represents a 25-year period of change on the S&P 500, the first covering 1970 to 1994, and the second covering 1995 to the present. Years are listed on the center line, with the rectangles above that line representing a company that was added to the index that year and rectangles below representing those companies taken off, all being color-coded based on their industry.

Above the entire timeline, we have added data points indicating certain world events that may have had an impact on the makeup of the index. These include events such as the multi-year recession of 1973-1975, which led to the year of the most churn in S&P history (1976), to the Dot-Com Bubble and the multiple major global financial crises of 2007-2008.



This timeline can help us to better understand how and why particular industries and companies have found success or failure at different times, giving a more complete picture of the index and the economy as a whole.

A Closer Look at Yearly Changes

For those interested in looking at some of the biggest changes in a given year, we have put together the following, which list the business sectors with the most companies that were added and removed from the index each year, as well as the total number of changes in that year. We have grouped this information together by decade to help keep them organized.