The market breadth is experiencing a historic improvement:

66% of stocks in the S&P 500 are outperforming the index since the beginning of the year, the highest level since data collection began in 1986.

This ratio has more than doubled compared to the extreme concentration levels seen in 2023, 2024, and 2025, when only 29%, 29%, and 31% of stocks outperformed the index, respectively.
This is even more positive than the dot-com bubble burst period from 2000-2002.
This means that 332 out of the members of the S&P 500 are exceeding the +0.7% increase of the index since the start of the year.
Interestingly, Nvidia, $NVDA, is the only stock in the "Big 7" group with a higher growth rate than the benchmark index so far this year.
Market leadership is becoming slightly broader.