The SPDR S&P 500 ETF Trust is an exchange-traded fund (ETF) 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 fund allows investors to buy shares that represent a diversified portfolio of these companies, making it easier to invest in the overall U.S. stock market. Launched in 1993, the SPDR S&P 500 ETF is one of the largest and most widely traded ETFs in the world. It provides a cost-effective way for investors to gain exposure to the U.S. equity market without having to purchase individual stocks.