The dominance of U.S. largest companies reached new heights on August 8, 2025, as Alphabet, Amazon, Apple, Berkshire Hathaway, Broadcom, Meta Platforms, Microsoft, Nvidia, Tesla, and Walmart commanded a record 40.2% of the S&P 500’s total value—up from 33.0% in 2023—and 35% of the entire U.S. stock market. Their combined market cap hit an unprecedented $22.8 trillion, intensifying concerns over market concentration and vulnerability to a handful of corporate giants.