New Delhi, Feb. 10 -- If you track the US stock market today through the headline index move, it can feel like a simple story: markets rise over time, so most stocks should eventually rise too. That's the comforting picture the index chart paints, especially when US Market Today coverage focuses on record levels and big themes.

But the mechanism of wealth creation in the US stock market is far more uneven than most investors realise.

Even during long bull runs, a surprisingly large share of companies fail to regain their old highs for years, sometimes decades. And yet, indices keep climbing. That isn't a contradiction. It's the defining feature of how equity markets work.

The hidden gap between "the market" and "a stock"When people say...