Market concentration is back on the rise: The top 10 stocks now reflect 37% of the S&P 500's market cap, near an all-time high. Since 2020, this percentage is now up 12 points. By comparison, at the 2000 Dot-Com Bubble peak, this metric stood at 27%. Meanwhile, the top 10 stocks' earnings account for 30% of all S&P 500 profits. This is significantly above the long-term average of ~20%. The market is highly reliant on big tech.