US AI Capex Surge Heightens Market Concentration Risks

US hyperscalers are forecast to spend about $700 billion on AI‑related capital expenditure in 2026, driving the weight of the "Magnificent 7" to nearly 25 % of the MSCI World Index and three semiconductor firms to 30 % of the MSCI Emerging Markets Index. The massive outlays are boosting S&P 500 returns and earnings growth, but they also raise concerns about an increasingly concentrated equity market.

Analysts project AI infrastructure spending to top $1 trillion in 2027 and reach $3‑4 trillion annually by 2030. U.S. data‑center power demand could climb to roughly 66 GW in 2027, more than double 2026 levels, putting pressure on the electric grid and financial markets. Asian chip makers such as Samsung, SK Hynix and Taiwan’s TSMC are benefitting from the supply‑chain lift, but investors are advised to diversify exposure to mitigate concentration risk.