The SPDR S&P 500 ETF is an exchange-traded fund that aims to track the performance of the S&P 500, a stock market index that includes 500 of the largest publicly traded companies in the United States. This ETF allows investors to buy shares that represent a diversified portfolio of these companies, making it easier to invest in the overall market. Launched in 1993, the SPDR S&P 500 ETF is one of the largest and most popular ETFs in the world. It trades on the New York Stock Exchange under the ticker symbol SPY, providing investors with liquidity and flexibility to buy or sell shares throughout the trading day.