One of the principal differences between a unit investment trust and a mutual fund is that a unit investment trust does not actively trade its investment portfolio. Rather, a unit investment trust buys relatively fixed securities (such as corporate and/or municipal bonds) and holds them for relatively long periods of time, with little or no trading. Since the portfolio is fixed, investors know exactly what they are investing in by reading the prospectus. Unit investment trusts also do not typically have boards of directors, corporate officers, or investment advisers. Unit investment trusts are also regulated under a specific Congressional act, the Investment Company Act of 1940, Sections 4 and 26.