John Hancock Preferred Income Fund is a closed-end, diversified management investment company. The Fund's investment objective is to provide a high level of current income, consistent with preservation of capital. It invests at least 80% of its assets (net assets plus borrowings for investment purposes) in preferred stocks and other preferred securities, including convertible preferred securities. The Fund invests 25% or more of its total assets in the industries composing the utilities sector; at least 50% in securities that are rated investment grade, or in unrated securities; up to 50% in securities that are rated below investment grade; at least 65% in securities that are rated investment grade or in unrated securities, and up to 35% in securities that are rated below investment grade. It invests in various sectors, such as consumer staples, food and staples retailing, banks, insurance and real estate investment trusts. Its investment adviser is John Hancock Advisers, LLC.