The MainStay DefinedTerm Municipal Opportunities Fund operates as a specialized closed-end investment vehicle, concentrating on fixed income securities. It is established and overseen by New York Life Investment Management LLC, with MacKay Shields LLC sharing co-management responsibilities. The fund primarily directs its capital toward U.S. debt markets, specifically focusing on high-quality municipal bonds that offer exemption from ordinary U.S. federal income taxation. Its performance is gauged against the Barclays Municipal Bond Index. This fund was initiated on June 26, 2012, and is domiciled within the United States.