New Delhi, Nov. 27 -- For years, India's stock market ran on the shoulders of a few giants. Not anymore. Trading activity and institutional money are now spreading across the widest set of companies in nearly a decade, with market concentration gauges such as the Herfindahl-Hirschman Index, or HHI, falling sharply from their pandemic highs and signalling a structural broadening of who gets attention and capital.

The market-cap-based HHI for the National Stock Exchange (NSE) peaked at an 11-year high of 173 in March 2020, when pandemic uncertainty funnelled money into the most liquid large-caps. By October 2025, it had eased to 80, lowest level since March 2018, reflecting a broadening of ownership and liquidity.

The HHI is calculated by...