Funds are considered securities. According to the different nature of property rights, marketable securities can be divided into three categories: commodity securities, currency securities and capital security. Capital security refers to the securities generated by financial investment or activities directly related to financial investment. Bondholders have a certain claim to the issuer's income, including stocks, bonds and their derivatives such as funds and convertible securities.

Funds can be divided into broad sense and narrow sense. Broadly speaking, a fund refers to a certain amount of funds set up for a certain purpose. In a narrow sense, funds mainly refer to securities investment funds.