Nvidia and 19 Other Stocks Now Make Up 50% of the S&P 500. Here's What It Means for Your Investment Portfolio.

The largest companies have contributed disproportionately to S&P 500 gains. An easy way to measure that is by comparing the S&P 500's performance to the S&P 500 Equal Weight Index, which effectively weights each S&P 500 component at 0.2% of the index. So, instead of Nvidia having over 350 times more influence than a company like Clorox in the S&P 500, their stock prices would have the same impact in the S&P 500 Equal Weight Index.This means that investor sentiment and earnings growth can drastically impact ...