Funds can be divided into broad sense and narrow sense. Broadly speaking, they refer to a certain amount of funds set up for a certain purpose, such as trust and investment funds, provident funds, retirement funds and so on. In a narrow sense, they refer to funds with specific purposes and uses. Usually, funds mainly refer to securities investment funds. The income of securities investment funds comes from the future, and the performance of the income is inseparable from the performance of the investment target market, which has certain risks. (1) According to whether the fund unit can be increased or redeemed, it can be divided into open-end funds and closed-end funds. Open-end funds are not traded on the market (as the case may be), but are purchased and redeemed by banks, brokers and fund companies, and the fund scale is not fixed; Closed-end funds have a fixed duration and are generally listed and traded on the stock exchange. Investors buy and sell fund shares through the secondary market.