The Top 15 Stocks in the S&P 500 Are Now 47% of the Value. In 2000 Bubble, It Was 27%

The top 15 stocks in the S&P 500 now account for a record 46.7% of the index's total value, up sharply from 27.2% at the peak of the 2000 Dot-Com Bubble. The concentration metric highlights how a handful of mega-cap names drive broader equity performance, raising comparisons to past bubble dynamics. For crypto traders, the story is a macro-risk signal rather than a direct catalyst, since extreme equity concentration could amplify volatility in risk assets if those leaders correct.