Firm that invests the pooled funds of retail investors for a fee. By aggregating the funds of a large number of small investors into a specific investments (in line with the objectives of the investors), an investment company gives individual investors access to a wider range of securities than the investors themselves would have been able to access. Also, individual investors should be able to save on trading costs since the investment company is able to gain economies of scale in operations. There are two types of investment companies: open-end (mutual funds) and closed-end (investment trusts). also called investment fund.