Short for Standard & PoorÂ’s 500 Depositary Receipts. A SPDR is an investment vehicle that tracks the return of the S&P 500 index or one of its subgroups. A SPDR is an exchange-traded fund (ETF), which essentially is a mutual fund-like instrument that is traded on stock exchanges. SPDRs make it easy for pension funds and other large institutions to gain exposure to the U.S. equity market without having to buy all 500 individual stocks in the S&P 500. They also are targeted at individual investors. SPDRs were introduced by the American Stock Exchange and are among its most popular ETFs. Other ETFs are Diamonds, Ishares, and Quebes (QQQ). See also Diamonds and Quebes.