Different from open-end funds, a typical feature of closed-end funds is that they have a certain closed period. During this period, the circulation of fund shares is listed on the stock exchange, and investors must bid for the fund shares in the secondary market through securities brokers.

This feature makes closed-end funds have two prices, one is the unit net value, which is managed by the fund manager; The other is the transaction price in the secondary market, which changes at any time, and this price may be different from the net value at the time of transaction. When the transaction price of closed-end funds in the secondary market is lower than the actual net value, this situation is called "discount".