The investment seeks to provide total return that closely corresponds, before fees and expenses, to the total return of the ICE BofA 15+ Year US Inflation-Linked Treasury Index. The fund invests at least 80% of its total assets (exclusive of collateral held from securities lending) in the component securities of the ICE BofA 15+ Year US Inflation-Linked Treasury Index (the underlying index). The underlying index is an unmanaged index comprised of Treasury Inflation-Protected Securities (TIPS) with a maturity of at least 15 years.