Investing Assets & Markets Stocks What Is the SPDR S&P 500 ETF (SPY)? The SPDR S&P 500 ETF (SPY) Explained By Cory Mitchell Cory Mitchell Facebook Twitter Cory Mitchell, Chartered Market Technician, is a day trading expert with over 10 years of experience writing on investing, trading, and day trading for publications including Investopedia, Forbes, and others. learn about our editorial policies Updated on May 31, 2022 Reviewed by Michael J Boyle Reviewed by Michael J Boyle Michael Boyle is an experienced financial professional with more than 10 years working with financial planning, derivatives, equities, fixed income, project management, and analytics. learn about our financial review board Fact checked by David Rubin Fact checked by David Rubin Facebook Instagram Twitter David J. Rubin is a fact checker for The Balance with more than 30 years in editing and publishing. The majority of his experience lies within the legal and financial spaces. At legal publisher Matthew Bender & Co./LexisNexis, he was a manager of R&D, programmer analyst, and senior copy editor. learn about our editorial policies Share Tweet Pin Email Definition The SPDR S&P 500 ETF (SPY) is an exchange-traded fund (ETF) that tracks the Standard & Poor's 500 (S&P 500) index. It does this by holding a portfolio of stocks in companies that are included in the S&P 500. Photo: Laurence Dutton / Getty Images Definition and Example of the SPDR S&P 500 ETF (SPY) The SPDR S&P 500 is an exchange-traded fund (ETF) that was created to provide an investment vehicle that produces returns roughly in line with the S&P 500 Index before expenses. The fund, known as "SPY" for its trading symbol on the NYSE Arca exchange, was the first ETF listed in the U.S. in January 1993 when introduced by State Street Global Advisors. "SPDR" stands for "Standard & Poor's Depositary Receipts." An ETF is a fund that owns securities like stocks, bonds, and mutual funds. Investors buy shares in the fund, but they don't own the underlying assets. ETF shares are traded on a stock exchange. SPY is a popular ETF and is consistently one of the highest-volume trading vehicles on U.S. exchanges. Its average volume is typically over 70 million shares, although that does fluctuate over time. Many investors and hedge funds use SPY because it represents the S&P 500 index—a basket of 500 major U.S. companies. The S&P 500 index is composed of U.S. companies across all Global Industry Classification Standard (GICS) sectors with an unadjusted market capitalization of $8 billion or greater. Each company in the index must also have had positive earnings in the most recent quarter and over the most recent four quarters. Note Investors use the SPDR S&P 500 ETF (SPY) because it provides exposure to a wide range of large U.S. companies with a single purchase. How the SPDR S&P 500 ETF (SPY) Works The SPDR S&P 500 is a unit investment trust, which means that SPY must attempt to fully replicate the S&P 500. The managers of the fund purchase and sell stocks to align their holdings with the S&P 500 index. When you buy a share of SPY, you're buying a unit of the current holdings representing a small portion of each stock in the S&P 500 index. Investors buy SPY hoping that the holdings within the fund—the stocks of the S&P 500 index—will rise. This allows them to sell their SPY units at a higher price than what they paid. If the holdings within the fund fall, the value of each unit/share of SPY will fall as well. SPY trades on the stock exchange, so traders can buy or sell their units to or from other market participants. Occasionally, the unit's price might not reflect the underlying value of the holdings within a unit, because the units are traded on an exchange. Euphoria or fear can cause buyers or sellers to push the price above or below the true value of the underlying holdings. Traders can view the true value of one SPY unit by looking up the symbol "SPY.NV." It's updated each morning with the value of holdings. NV indicates net asset value. Alternatives to SPDR S&P 500 ETF (SPY) While SPY is the biggest ETF tracking the S&P 500, it's far from the only one. One popular alternative is the Vanguard S&P 500 ETF (VOO), which also tracks the index and offers a lower net expense ratio than SPY (0.03% vs. SPY's 0.09%) as of March 2022. The expense ratio is the percentage of a fund's assets that are used for administrative expenses. It's essentially a fee you pay for buying a professionally managed product. Another competitor, iShares Core S&P 500 ETF (IVV), also offers an expense ratio of 0.03%. Key Takeaways The SPDR S&P 500 ETF (SPY) is an exchange-traded fund (ETF) that tracks the Standard & Poor's 500 (S&P 500) index. The SPDR S&P 500 exchange-traded fund (ETF) is designed to produce returns roughly in line with the S&P 500 Index before expenses. The managers of the fund purchase and sell stocks to align their holdings with the S&P 500 index.You can find many alternatives to the SPDR S&P 500 ETF, including the Vanguard S&P 500 ETF and the IShares Core S&P 500 ETF. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit Sources The Balance uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. ETF.com. "SPY SPDR S&P 500 ETF Trust." State Street Global Advisors. "SPDR S&P 500® ETF Trust." S&P Dow Jones Indices. "S&P 500," Page 1. U.S. Securities and Exchange Commission. "SPDR® Exchange Traded Funds: Basics of Product Structure." State Street Global Advisors. "SPDR® S&P 500® ETF Trust: Prospectus Dated January 28, 2022," Pages 4-6, 62-63. Yahoo Finance. "SPDR S&P 500 ETF Trust (SPY)." Yahoo Finance. "Vanguard S&P 500 ETF (VOO)." Yahoo Finance. "iShares Core S&P 500 ETF (IVV)."