34% of the S&P 500's Value Comes From Just 8 Stocks

The S&P 500 index is a benchmark used to gauge the broader U.S. market. Its 500 large-cap and megacap components come from every sector of the economy, and reflect investing categories from value to growth. As those companies account for about 80% of the value of the U.S. stock market, the S&P 500 makes a fairly good proxy for it.However, each company's weight in the index is proportional to its market cap, and some companies have in recent years grown so big that now, just a few have a disproportionate amo ...