The Standard and Poor's 500, or simply the S&P 500, is a stock market index tracking the stock performance of 500 leading companies listed on stock exchanges in the United States. It is one of the most commonly followed equity indices and includes approximately 80% of the total market capitalization of U.S. public companies, with an aggregate market cap of more than $49.8 trillion as of March 31, 2025. The S&P 500 index is a Free-float weighted/capitalization-weighted index. As of April 2025, the ten largest companies on the list of S&P 500 companies accounted for approximately 35% of the market capitalization of the index and were, in order of highest to lowest weighting: Apple, Microsoft, Nvidia, Amazon.com, Alphabet, Meta Platforms, Berkshire Hathaway, Broadcom, Tesla, and JPMorgan Chase. The components that have increased their dividends in 25 consecutive years are known as the S&P 500 Dividend Aristocrats. Companies in the S&P 500 derive a collective 72% of revenues from the United States and 28% from other countries. The index is one of the factors in computation of the Conference Board Leading Economic Index, used to forecast the direction of the economy. Wikipedia