A fund in a broad sense refers to a certain amount of funds set up for a certain purpose, mainly including trust and investment funds, provident funds, insurance funds, retirement funds and funds of various foundations. In a narrow sense, funds refer to funds with specific purposes and uses. In practice, funds mainly refer to securities investment funds. Securities investment fund refers to an investment tool that forms an independent fund property by selling the funds raised by fund shares, which is managed by the fund manager and the fund custodian, and makes securities investment in the form of portfolio, and the fund share holders enjoy the benefits and bear the risks according to their shares.

Securities investment funds can be divided into the following categories according to different standards:

1, which can be divided into open-end funds and closed-end funds according to whether the fund units can be increased or redeemed.

2. According to different organizational forms, it can be divided into corporate funds and contractual funds. China's securities investment funds are all contractual funds.

3. According to the difference of investment risk and income, it can be divided into growth fund, income fund and balanced fund.

4. According to different investors, it can be divided into four categories: money fund, bond fund, hybrid fund and stock fund.