Stock price increases associated with addition to the S&P 500 Index have been interpreted as evidence that demand curves for stocks slope downward. A key premise underlying this interpretation is that Index inclusion provides no new information about companies' future prospects. We examine this...

Using a sample of 44,288 firm-years between 1984 and 1997, we document an increase in the extent of global diversification over time. This trend does not reflect a substitution of global for industrial diversification. We also find that global diversification results in average valuation...