History of S&P 500 in Timeline

The S&P 500 is a stock market index that tracks the performance of 500 of the largest publicly traded companies in the United States. Representing about 80% of the total U.S. equity market capitalization, it's a widely followed indicator of overall market health. As of December 31, 2025, the S&P 500 had an aggregate market capitalization exceeding $61.1 trillion. It is commonly used as a benchmark for investment portfolios and mutual funds. Its performance provides insights into the broader U.S. economy.

1860: Poor's Publishing Formed

In 1860, Henry Varnum Poor formed Poor's Publishing, which published an investor's guide to the railroad industry.

1906: Standard Statistics Bureau Founded

In 1906, the Standard Statistics Bureau was founded, later becoming the Standard Statistics Company.

1923: Standard Statistics Company's First Index

In 1923, the Standard Statistics Company developed its first stock market index, consisting of 233 U.S. companies, computed weekly.

1926: Inception of S&P Index

Since its inception in 1926, the S&P index's compound annual growth rate—including dividends—has been approximately 9.8% (6% after inflation).

1941: Formation of Standard & Poor's

In 1941, Poor's Publishing merged with Standard Statistics Company to form Standard & Poor's.

March 4, 1957: Expansion of S&P 500

On March 4, 1957, the index was expanded to its current extent of 500 companies and was renamed the S&P 500 Stock Composite Index.

1962: Ultronic Systems Compiles S&P Indices

In 1962, Ultronic Systems became the compiler of the S&P indices, including the S&P 500 Stock Composite Index.

August 31, 1976: First S&P 500 Mutual Fund

On August 31, 1976, The Vanguard Group offered the first mutual fund to retail investors that tracked the index.

April 21, 1982: S&P 500 Futures Trading Begins

On April 21, 1982, the Chicago Mercantile Exchange began trading futures based on the S&P 500 index.

1982: Original SP big contract began trading

The original SP big contract began trading in 1982.

July 1, 1983: S&P 500 Options Trading Begins

On July 1, 1983, the Chicago Board Options Exchange began trading options based on the S&P 500 index.

1986: S&P 500 Price Updates

Beginning in 1986, the S&P 500 index value was updated every 15 seconds during trading hours, disseminated by Reuters.

January 22, 1993: S&P Depositary Receipts ETF

On January 22, 1993, the Standard & Poor's Depositary Receipts exchange-traded fund (ETF) issued by State Street Corporation began trading.

September 9, 1997: S&P E-mini Futures Contract Introduced

On September 9, 1997, CME Group introduced the S&P E-mini futures contract.

2005: Transition to Public Float-Adjusted Weighting

In 2005, the S&P 500 index transitioned to a public float-adjusted capitalization-weighting.

September 17, 2021: Final Trading Date for Original SP Big Contract

Friday, September 17, 2021, was the final trading date for the original SP big contract, which began trading in 1982.

October 2021: NBER Study on S&P Ratings

In October 2021, a study by the National Bureau of Economic Research suggested that companies purchasing ratings services from S&P Global may improve their chances of entering the S&P 500.

December 24, 2025: S&P 500 Record Closing High

On December 24, 2025, the S&P 500 set a record closing high of 6,932.05 after an intra-year correction.

December 31, 2025: S&P 500 Market Cap

On December 31, 2025, the S&P 500's aggregate market capitalization was more than $61.1 trillion.

January 2026: Top 10 S&P 500 Companies

In January 2026, the 10 largest companies in the S&P 500 were, in order of weighting: Nvidia, Alphabet (Class A & C shares), Apple, Microsoft, Amazon, Broadcom, Meta Platforms, Tesla, Berkshire Hathaway, and Lilly (Eli).