The index seeks to track the investment results of an index composed of U.S. dollar-denominated, investment-grade corporate bonds maturing in 2055. The fund will invest at least 80% of its assets in the component instruments of the underlying index, and the fund will invest at least 90% of its assets in fixed income securities of the types included in the underlying index that BFA believes will help the fund track the underlying index. The fund is non-diversified. The fund is non-diversified.