The investment seeks to track the investment results of the Russell 1000® Index, which measures the performance of large- and mid- capitalization sectors of the U.S. equity market. The fund generally invests at least 80% of its assets in the component securities of its underlying index and in investments that have economic characteristics that are substantially identical to the component securities of its underlying index and may invest up to 20% of its assets in certain futures, options and swap contracts, cash and cash equivalents.