iShares Russell Midcap Growth Index Fund (the Fund) seeks investment results that correspond generally to the price and yield performance of the Russell Midcap Growth Index (the Index). The Index measures the performance of the mid-capitalization growth sector of the United States equity market. It is a subset of the Russell Midcap Index. The Index is a capitalization-weighted index and consists of those companies or portion of a company, with higher price-to-book ratios and higher forecasted growth within the Russell Midcap Index. Component companies are adjusted for available float and must meet objective criteria for inclusion to the Index. The Index represents approximately 48% of the total market capitalization of the Russell Midcap Index. 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.