It is possible in theory. However, the fund manager is a professional expert in stock trading, with rich experience and inside information. Even several funds can jointly manipulate stocks, so it is unlikely to lose all. Historically, when the stock market was at its lowest ebb, the lowest fund only lost a few cents. Of course, it is unrealistic to expect the fund to make big money. Recently, the stock market has performed well, and few funds have outperformed the stock market (that is, the rate of return has not exceeded the stock index).