iShares Russell Mid-Cap ETF (the Fund), formerly iShares Russell Midcap Index Fund, is an exchange-traded fund (ETF). The Fund seeks investment results that correspond generally to the price and yield performance of the Russell Midcap Index (the Index). The Index measures the performance of the mid-capitalization sector of the United States equity market. The Index is a float-adjusted, capitalization-weighted index of the 800 smallest issuers in the Russell 1000 Index. The Index includes equity securities issued by issuers, which range in size between approximately $1.7 billion and $12 billion, though these amounts may change from time to time. The Index is a subset of the Russell 1000 Index and serves as the underlying index for the Russell Midcap Growth and Value Index series. The Fund invests in a representative sample of securities included in the Index that collectively has an investment profile similar to the Index. The Fund’s investment advisor is BlackRock Fund Advisors.