The S&P 500 has never been this concentrated in just 2 stocks

Apple (AAPL) and Nvidia (NVDA) have truly become the straws that stir the stock market's drink. The S&P 500 (^GSPC) has never been more concentrated in just two stocks than it is today, Creative Planning president Peter Mallouk pointed out. Nvidia and Apple represent over 15% of the index (see chart below). That percentage dusts the 9.1% concentration seen for Microsoft (MSFT) and General Electric (GE) in the lead-up to the dot-com bust.Apple and Nvidia, VIP stocks. Nvidia and Apple are on quite a run, which helps to explain their rising importance to the S&P 500. Apple stock hit $345 on Tuesday, marking an all-time high for the iPhone maker's shares.