A structured product is a single investment, usually issued as a note or debenture, whose return is defined by a formula linked to an underlying such as an equity index. Instead of simply rising and falling with the market, it pays according to rules agreed in advance.
Underneath, most structures are built from two ingredients: a bond that provides a base of value, and one or more options that shape the upside and downside. Combining them lets an issuer engineer almost any payoff profile.