Holidays.
Bond funds are during national statutory holidays and weekends, and their income is not updated, or they neither make money nor lose money. Thursday of the 30th day of CICC Anyi is a holiday.
Whether it is a stock fund or a bond fund, the net value of the fund will fluctuate with the market. If the market goes up, it will generate income, and if it goes down, the income or principal will be deducted. Sometimes it will maintain a balance if it does not rise or fall.
Neither make nor lose money.