The fund generally will invest at least 80% of its total assets in securities that comprise the underlying index. The index seeks to measure the performance of a portfolio of U.S. dollar-denominated high yield corporate bonds (commonly known as "junk bonds") with maturities or, in some cases, "effective maturities" in the year 2028. It does not purchase all of the securities in the index; instead, the fund utilizes a "sampling" methodology to seek to achieve its investment objective.