The investment seeks to track the investment results (before fees and expenses) of the Nasdaq BulletShares® USD High Yield Corporate Bond 2021 Index (the "underlying index"). The fund generally will invest at least 80% of its total assets in securities that comprise the underlying index. The underlying 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 2021 (collectively, "2021 Bonds"). The fund is non-diversified.