Global markets are showing heightened sensitivity as the rally gets increasingly top-heavy, led by mega-cap tech stocks while breadth remains weak. Analysts highlight that even though indices are at fresh highs, the underlying participation rate is narrowing. Institutional trading desks warn that if upcoming earnings disappoint or policy signals disappoint, volatility could increase sharply. The confluence of stretched valuations, heavy debt loads in tech infrastructure and geopolitical risks may leave markets vulnerable to reversals despite the near-term bullish posture.