Nuveen Floating Rate Income Opportunity Fund is a diversified closed-end management investment company. The Fund's investment objective is to achieve a high level of current income. The Fund invests approximately 80% of its managed assets in adjustable rate loans, primarily secured senior loans. As part of the 80% requirement, the Fund also may invest in unsecured senior loans and secured and unsecured subordinated loans. The Fund invests approximately 65% of its managed assets in adjustable rate senior loans that are secured by specific collateral. The Fund's portfolio consists of various sectors, including media; software; pharmaceuticals; diversified telecommunication services; diversified consumer services; food products; wireless telecommunication services; real estate investment trust; technology hardware, storage and peripherals; healthcare equipment and supplies; airlines, and insurance. The Fund's investment advisor is Nuveen Fund Advisors, LLC.