Nuveen High Income December 2018 Target Term Fund is a diversified, closed-end management investment company. The Fund’s investment objectives are to provide a high level of current income and to return original net asset value (NAV) to common shareholders on or about the termination date. The Fund seeks to achieve its investment objectives by investing, normally, at least 80% of its managed assets in corporate debt securities, and separately at least 80% of its managed assets in securities that, at the time of investment, are rated below investment grade (BB+/Ba1 or lower) or are unrated but deemed equivalent by the sub adviser. The Fund’s portfolio consists of a range of investments, including high yield securities (junk bonds), corporate debt securities, bonds, non-united states and emerging markets issuers, senior loans, subordinated loans, preferred securities, convertible securities, illiquid securities and derivatives. Nuveen Fund Advisors is the investment adviser of the Fund.