How we got hereThe Mag-7’s share of S&P 500 market cap was around 18.5% in early 2020. The cap-weighted S&P 500 dropped around 20% over the same period, while an equal-weighted version of the index declined about 13%. Nvidia’s central role in AI infrastructure buildout makes chip supply a systemic concern, not just a company-specific one. US hyperscalers are projected to spend around $700 billion on AI infrastructure in 2026, up from approximately $380 billion in 2025. The equal-weighted S&P 500 approach, while it underperforms during tech bull runs, offers a structurally different risk profile.