Volatile Chipmaker Stocks Emerge as Key Driver of S&P 500 Rally

Shares of chipmakers are increasingly dominating the S&P 500 Index, powering stocks to record highs while stirring concerns over the rally’s durability.

A selloff on Friday brought those worries to the forefront, as the benchmark fell 1.2% in its biggest drop since March while a gauge of chipmakers sank 4%. For most of 2026, however, the two have risen together, with a handful of semiconductor companies accounting for more than half of the 8% gain in the S&P 500 this year. Winners include bull market mainstay Nvidia Corp., as well as Sandisk Corp., which has climbed almost 500% year-to-date and Micron Technology Inc., whose shares have more than doubled.