Fixed bonds, generally designated open-end bond funds. Regular open debt base is an innovative closed debt base, which combines the advantages of open-end funds and closed-end funds and adopts a combination of closed operation and regular opening. Compared with the common closed-end debt base, the regular open debt base improves the liquidity of products. At present, the closed period of debt-based funds that are regularly opened in the market is generally 1 to 3 years, and some debt-based funds are as short as 6 months or adopt the quarterly restricted opening mode, which meets the needs of different types of investors. Compared with the common open-ended debt base, the regular open-ended debt base can increase the income by increasing leverage during the closed period, and the closed operation can reduce the pressure of fund redemption, which is more conducive to fund manager management. Some regularly opened debt bases can also be traded in the secondary market to meet the needs of investors in the market, but there are certain discounts and liquidity risks.