The SPDR S&P 500 ETF Trust is a very liquid exchange-traded fund which trades on the NYSE Arca under the symbol SPY. The ETF is designed to track the S&P 500 index by holding a portfolio comprising all 500 companies on the index. It is a part of the SPDR family of ETFs and is managed by State Street Global Advisors. The fund is the largest and oldest ETF in the USA. Legally, the fund is set up as a unit investment trust. It has a net expense ratio of 0.0945%, its CUSIP is 78462F103, and its ISIN is US78462F1030. Wikipedia