SPDR S&P 500 ETF Trust

SPDR funds (pronounced "spider") are a family of exchange-traded funds (ETFs) traded in the United States, Europe, Mexico and Asia-Pacific and managed by State Street Global Advisors (SSGA). Informally, they are also known as Spyders or Spiders. SPDR is a trademark of Standard and Poor's Financial Services LLC, a subsidiary of S&P Global. The name is an acronym for the first member of the family, the Standard & Poor's Depositary Receipts, now the SPDR S&P 500 Trust ETF, which is designed to track the S&P 500 stock market index. SPDR is the third largest ETF provider, behind iShares and Vanguard.

The SPDR S&P 500 Trust is the largest ETF in the world by total assets under management. SSGA also manages the SPDR Gold Shares, the largest commodity based ETF in the world.

The funds are formulated as unit investment trusts. In 2007, SSGA rebranded its other United States ETFs as SPDRs, including the StreetTRACKS family and its other flagship ETF shares, the DOW DIAMONDS, that tracks the Dow Jones Industrial Average. This move united all U.S. ETFs managed by SSGA, a total of 23 at that time, under a single brand.