Fund Description: SPDR Portfolio Mortgage Backed Bond ETF, formerly SPDR Barclays Mortgage Backed Bond ETF is an exchange-traded index fund or Index ETF which is a separate investment portfolio of the SPDR Series Trust, an investment management company. INVESTMENT OBJECTIVE: The SPDR Portfolio Mortgage Backed Bond ETF seeks to provide investment results that, before fees and expenses, correspond generally to the price and yield performance of the Bloomberg Barclays U.S. MBS Index, formerly Barclays U.S. MBS Index. INDEX DESCRIPTION: The Bloomberg Barclays U.S. MBS Index is designed to measure the performance of the U.S. agency mortgage pass-through segment of the U.S. investment grade bond market. U.S. agency mortgage pass-through security refers to a category of pass-through securities backed by pools of mortgages and issued by one of the following U.S. government-sponsored enterprises: Government National Mortgage Association (GNMA); Federal National Mortgage Association (“FNMA”) and Federal Home Loan Mortgage Corporation (FHLM). The Index is market capitalization weighted and the securities in the Index are updated on the last calendar day of each month. FUND STRATEGY: In seeking to track the performance of the 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. The Fund is generally expected to hold less than the total number of securities in the Index, but reserves the right to hold as many securities as it believes necessary to achieve the Fund's investment objective. Under normal market conditions, the Fund generally invests substantially all, but at least 80%, of its total assets in the securities comprising the Index or in securities that has been determined to have economic characteristics that are substantially identical to the economic characteristics of the securities that comprise the Index. The Fund may invest in securities that are not included in the Index, futures, options, swap contracts and other derivatives, cash and cash equivalents or money market instruments, such as repurchase agreements and money market funds (including money market funds. FUND MANAGEMENT: SSgA FM serves as the investment adviser to the Fund.