AI now represents 39% of the S&P 500. That's approaching the concentration extremes seen during history's biggest bubbles. Yet everyone keeps talking about rotation.

A sharp rise in AI infrastructure spending has catapulted many tech stocks in the US to huge returns over the past 12 months. Technology accounts for almost all of the top gainers…

AI now represents 39% of the S&P 500. That's approaching the concentration extremes seen during history's biggest bubbles. Yet everyone keeps talking about rotation.