Strategy. In seeking to track the performance of the S&P SmallCap 600 Index (the Index), the Fund employs a sampling strategy, which means that the Fund is not required to purchase all of the securities represented in the Index. Instead, the Fund may purchase a subset of the securities in the Index in an effort to hold a portfolio of securities with generally the same risk and return characteristics of the Index. The quantity of holdings in the Fund will be based on a number of factors, including asset size of the Fund. Based on its analysis of these factors, SSGA Funds Management, Inc. (SSGA FM or the Adviser), the investment adviser to the Fund, either may invest the Fund's assets … Show more… In seeking to track the performance of the S&P SmallCap 600 Index (the Index), the Fund employs a sampling strategy, which means that the Fund is not required to purchase all of the securities represented in the Index. Instead, the Fund may purchase a subset of the securities in the Index in an effort to hold a portfolio of securities with generally the same risk and return characteristics of the Index. The quantity of holdings in the Fund will be based on a number of factors, including asset size of the Fund. Based on its analysis of these factors, SSGA Funds Management, Inc. (SSGA FM or the Adviser), the investment adviser to the Fund, either may invest the Fund's assets in a subset of securities in the Index or may invest the Fund's assets in substantially all of the securities represented in the Index in approximately the same proportions as the Index, as determined by the Adviser to be in the best interest of the Fund in pursuing its objective. The Fund is classified as diversified under the Investment Company Act of 1940, as amended; however, the Fund may become non-diversified solely as a result of tracking the Index (e.g., changes in weightings of one or more component securities). When the Fund is non-diversified, it may invest a relatively high percentage of its assets in a limited number of issuers. Under normal market conditions, the Fund generally invests substantially all, but at least 80%, of its total assets in the securities comprising the Index. In addition, in seeking to track the Index, the Fund may invest in equity securities that are not included in the Index, cash and cash equivalents or money market instruments, such as repurchase agreements and money market funds (including money market funds advised by the Adviser). In seeking to track the Index, the Fund's assets may be concentrated in an industry or group of industries, but only to the extent that the Index concentrates in a particular industry or group of industries. Futures contracts (a type of derivative instrument) may be used by the Fund in seeking performance that corresponds to the Index and in managing cash flows. The Index measures the performance of the small-capitalization segment of the U.S. equity market. The selection universe for the Index includes all U.S. common equities listed on the NYSE, NYSE Arca, NYSE American, NASDAQ Global Select Market, NASDAQ Select Market, NASDAQ Capital Market, Cboe BZX, Cboe BYX, Cboe EDGA, or Cboe EDGX with unadjusted market capitalizations between $850 million and $3.7 billion and float-adjusted market capitalizations of at least $425 million at the time of inclusion. These capitalization ranges may be revised by the Index Provider (as defined below) at any time. To be included in the Index, a security (or issuer of a security, as applicable) should (i) have an annual dollar value traded to float-adjusted market capitalization ratio of 1 or greater; (ii) trade a minimum of 250,000 shares in each of the six months leading up to the evaluation date; (iii) have a public float of at least 10%; and (iv) have positive aggregate earnings over the four most recent quarters and for the most recent quarter. In selecting securities for inclusion in the Index, the Index Provider also considers sector balance by comparing the weight of each GICS (Global Industry Classification Standard) sector in the Index to its weight in the relevant market capitalization range of the S&P Total Market Index. The Index is float-adjusted market capitalization weighted. Index constituents are added and removed on an as-needed basis. The Index is rebalanced on a quarterly basis in March, June, September and December. As of August 31, 2022, a significant portion of the Fund comprised companies in the industrial and financial sectors, although this may change from time to time. As of July 31, 2022, the Index comprised 601 stocks. The Index is sponsored by S&P Dow Jones Indices LLC (the Index Provider), which is not affiliated with the Fund or the Adviser. The Index Provider determines the composition of the Index, relative weightings of the securities in the Index and publishes information regarding the market value of the Index. Show less