Fund funds have broad and narrow definitions. Fund in a broad sense is the general name of institutional investors, including trust and investment funds, unit trust funds, provident funds, insurance funds, retirement funds and funds of various foundations. Funds in the existing securities market, including closed-end funds and open-end funds, have the characteristics of income function and value-added potential.

From the accounting point of view, capital is a narrow concept, which refers to funds with specific purposes and uses. Because the investors of government agencies and institutions do not require investment returns and investment recovery, but require funds to be used for designated purposes in accordance with the law or the wishes of the investors, funds are formed.