Any complex security that includes features of two or more basic securities. One of the most common combination securities is a convertible bond, which is a bond that may be exchanged for common stock. In other words, a convertible bond combines features of bonds (with a fixed return and repayment at maturity) with features of stocks (with equity in the issuing company and the possibility of a high return).
A security that combines the attributes of two or more individual securities. An example of a combination security is a convertible bond that is part debt and part common stock.