Stock market concentration

The stock market has seen a significant rise, driven primarily by a small number of companies known as the 'Magnificent Seven,' including Apple, Amazon, and Microsoft. These seven companies make up 30% of the market value of the S&P 500. The concentration of market gains in a handful of companies has not been seen since the dot-com boom. There are various explanations for this, including herd mentality and a flight to safety, as well as the potential for these companies to be leading the market or acting as an aberration. This concentration raises concerns about capital allocation and the efficiency of the market.