The SPDR S&P Oil & Gas Equipment & Services ETF (Ticker: XES) seeks to replicate as closely as possible, before expenses, the total return performance of the S&P Oil & Gas Equipment & Services Select Industry Index. The index represents the oil and gas equipment and services sub-industry portion of the S&P Total Market Index (TMI). The S&P TMI tracks all the US common stocks regularly traded on the NYSE, American Stock Exchange, NASDAQ National Market and NASDAQ Small Cap Exchanges. The index holds approximately 23 stocks. Constituents are equal weighed at the beginning of each quarter and then float with the market for the rest of the quarter.