If you give money to the fund manager, it is equivalent to hiring him to help you manage your money. There is also the deepest problem, that is, the agency problem. Because of this agent problem, investors are most worried about: how to ensure that the fund manager treats my money with 100% energy responsibility? After all, people are selfish, and it is normal for fund managers to protect their own interests first, not those of investors. There is only one solution to this problem: I need the fund manager to put his money in this fund, so he will take my money as his own. Of course, it is impossible for a fund manager to put only a little money, but a large part of his own property, so that I can ensure that he is really interested in this fund.