The investment seeks to track the investment results (before fees and expenses) of the Nasdaq BulletShares® USD 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 investment grade corporate bonds with maturities or, in some cases, effective maturities in the year 2021 (collectively, 2021 Bonds).