In mainland China, the general Dao investors do not use the term mutual funds but instead replace them with investment funds, securities investment funds and so on, but the connotation of these terms is quite different from that of mutual funds. Early British investment trusts were closed-end funds, which could not issue new units or shares at will. After the completion of closed-end fund raising, investors no longer buy from fund companies directly or indirectly, but trade with each other in the stock market. Therefore, the size of the fund will not increase or decrease due to trading. Modern investment funds are no longer limited to closed-end funds, but there is an open-end fund, which can continuously issue fund units or fund shares according to the needs of investors. Investors buy and sell funds directly from fund companies or their agents, and the fund size will increase with the investors' trading.