In particular, semiconductor specialist Nvidia is viewed as the engine powering the AI vehicle right now. Demand for its most powerful graphics processing units (GPUs) has been off the charts, and investors have cheered on the stock accordingly. That said, many use cases for AI remain largely overlooked by investors.

Investors have found another major way to play the artificial-intelligence trend besides semiconductor stocks, and that’s led to a changing of the guard atop this year’s list of the best S&P 500 performers.

Ever since shares of Nvidia (NVDA) reached an all-time high in June, the chipmaker’s stock has experienced some turbulence — but its market cap is still up over 150% so far this year.

Some investors have been concerned about the ongoing liquidation of Nvidia shares by the company's CEO. However, there are plenty of reasons to sell stock, particularly if stock options make up a large part of an executive's compensation package.