New Delhi, Feb. 11 -- On the surface, the US stock market looks healthy. Major indices such as the S&P 500 and Nasdaq remain resilient, volatility appears contained, and long-term trends continue to favour global leaders like Apple, Microsoft and Nvidia. For many investors, that's enough reassurance.

But markets are rarely that simple. Beneath strong indices, individual stock performance is diverging sharply. As 2026 approaches, this gap is widening and it's changing how returns are generated.

Indices aggregate performance but they don't reflect how uneven returns can be. A small group of stocks can lift the index, while many others lag or decline.

This phenomenon, often called concentrated returns, becomes more pronounced as markets m...