So far this year, only 30% of the constituent stocks in the S&P 500 Index have outperformed the large cap, which is slightly higher than the 29% in 2023. According to historical statistics, such low levels of consecutive relative ratios have only occurred during the Internet bubble in 2000. In contrast, the historical median is 49%, which usually signifies healthy market breadth. Undoubtedly, behind the 12% annual rise in the S&P 500 Index, it was mainly driven by a few large technology stocks. The far-reaching impact of a few stocks on the entire market also means that stock selection is becoming increasingly crucial for US stock investment returns.