Although some studies have documented that there is a price increase for firms added to the S&P 500 Index other studies show mixed results. A more recent research suggests that managers are under greater scrutiny once they are added to the S&P500, and work harder to improve firm performance....

In this study we extend the work of Vijh (1994), Barberis, Shleifer, and Wurgler (2005), Denis, McConnell, Ovtchinnikov and Yu (2003) and Geppert, Ivanov and Karels (2011) by examining the effects of the addition to or deletion from the S&P 500 index on the firm's Fama - French four factor model...