Different operating modes of funds, different trading places and ways, the liquidity of fund products is also different. For example, closed-end funds are mainly traded through exchanges; Open-end funds are mainly purchased and redeemed at fund direct sales and consignment outlets; Individual open-end fund varieties, such as ETF, can be listed and traded on the exchange, and can also be purchased and redeemed through portfolio securities in the primary market. In addition, the operating characteristics of funds with different operating modes will be different. For example, in the operation of open-end funds, some cash should be reserved for redemption, while the liquidity requirements of closed-end fund portfolio operation will be lower, so the risk-return characteristics of the two types of funds are inevitably different.