It's official: The top 10% largest US stocks now reflect a record 76% of the US equity market. This has officially surpassed the previous record set before the Great Depression in the 1930s. By comparison, at the 2000 Dot-Com Bubble peak, the top 10%'s share was at ~73%. In the 1980s, this figure was below 50%. Meanwhile, the top 10 stocks in the S&P 500 now represent a record 40% of the index’s market cap. We are witnessing history.