The investment seeks to track the investment results of an index composed of U.S. real estate investment trusts ("REITs") that hold U.S. residential and commercial mortgages. The fund generally invests at least 90% of its assets in securities of the underlying index and in depositary receipts representing securities of the underlying index. The underlying index measures the performance of the residential and commercial mortgage real estate, mortgage finance and savings associations sectors of the U.S. equity market. The fund is non-diversified.