SPDRs Definition
SPDRs stand for Standard and Poor’s Depositary Receipts. Known as "Spiders," a SPDR is a unit investment trust that holds shares of all of the companies in the Standard & Poor’s 500 Composite Stock Price Index (S&P 500). SPDRs closely track the price performance and dividend yield of the S&P 500. There are also SPDRs that represent other indexes or particular industry groups.