"Traditional stock indexes, such as the S&P 500 and even the MSCI World Index, are deeply flawed. They do not weight their members equally, but rather according to their market values. This means they put the most weight on the biggest and most expensive stocks and markets. Today, Apple alone makes up 3 percent of the S&P 500. The U.S., which makes up less than 20 percent of the global economy, accounts for about 50 percent of the MSCI World Index.Inevitably, this means these indexes, and the money managers who follow them, put too much weight on the most fashionable and overvalued assets at the worst times—Japan in 1989, technology stocks in 1999, banks in 2006."