Nvidia accounts for 13% of the S&P 500’s 23% rally since March 30

The S&P 500 has climbed 23% since March 30, 2026. Ten stocks did roughly 70% of the work. At the front of that line is Nvidia, which alone contributed 13% of the index’s advance over the period. One chipmaker, an outsized share of the gains Nvidia’s weight in the S&P 500 reached about 8% in September 2026. That is the highest concentration for any single stock in more than 50 years. The company’s market capitalization sat at approximately $5.8 trillion to $6 trillion as of early October 2026. Over the rally, Nvidia added about $1.2 trillion in market value to the index on its own. As of early October, Nvidia shares were up approximately 28% year-to-date. The S&P 500 had gained a more modest 13% to 14% over the same stretch. The fundamentals behind the run Nvidia reported $96.2 billion in revenue for its fiscal second quarter of 2027, driven by demand for data center hardware and AI computing. Nvidia projected full-year revenue growth of about 70% for fiscal 2028. Semiconductor stocks as a group made up roughly 5% of the S&P 500 in 2020. By mid-2026, that share had climbed to approximately 19.7%. What this means for investors With chips at roughly 19.7% of the index ...