Fund is an indirect way of securities investment. By issuing fund shares, fund management companies concentrate investors' funds, which are managed by fund custodians (that is, qualified banks) and managed and used by fund managers to invest in financial instruments such as stocks and bonds, and then * * * bear the investment risks and share the benefits. According to whether fund units can be increased or redeemed, they can be divided into open-end funds and closed-end funds. When can I buy and sell open-end funds, what is the cost of open-end funds, and how to determine the price of open-end fund transactions? Today, I will introduce you to the related knowledge of open-end fund trading. Investors need to buy and sell funds on the open day stipulated in the fund contract, which is generally the trading day of Shanghai Stock Exchange and Shenzhen Stock Exchange. The specific business processing time is generally determined by the fund manager and the sales organization. However, applications accepted after the closing of the Stock Exchange (currently at 3 pm) can only be counted as applications accepted on the next open day. Closed period refers to a period of time after the establishment of a fund that does not accept redemption. Because newly established funds need a relatively long period to gradually complete the shareholding layout according to market conditions, fund contracts generally have a closed period. According to China's "Pilot Measures for Open-end Securities Investment Funds", the closed period after the establishment of open-end funds shall not exceed 3 months. If the fund closure period is too short, there will be a problem that the fund must be redeemed before the layout is completed, which will affect the net value of the fund unit and the rights and interests of investors. Therefore, the short closure period may be relatively risky. Fund investment should be long-term, and investors should not take the length of the closed period as the standard for selecting funds.