Investments that that Mutual Funds cant make?

According to the Investment Company Act of 1940 Mutual Funds cant buy securities on margin. (long term) and cant sell stock short.

Open-end management companies (mutual funds) and publicly traded (closed-end) funds can not buy on margin and sell short short. There is no requirement that investment companies beat the market, keep fees low, borrow from banks or have all of their money in one stock, few stocks or one industry or market sector.