The fund is an actively managed exchange-traded fund (ETF) that seeks high current income and long-term capital appreciation by investing in unaffiliated closed-end funds that the fund's investment adviser, Calamos Advisors LLC, believes offer both attractive income opportunities as well as arbitrage opportunities resulting from such closed-end funds trading at attractive discounts. Under normal circumstances, the fund seeks to achieve its investment objectives by investing at least 80% of its net assets in U.S. and non-U.S. closed-end funds. The fund is non-diversified.