What is Spy Etf? The SPDR S&P 500 ETF Trust (NYSE: SPY) is an exchange-traded fund (ETF) that seeks to track the performance of the S&P 500 Index. The S&P 500 Index is a widely followed measure of U.S. stock market performance. As of September 30, 2016, the fund had $202.9 billion in assets under […]