Many funds have decidedly bumpy rides, some even nosedive. The extent to which your investment fluctuates will, of course, depend on the type of fund you hold and the expertise of the manager. The bottom line here is that although mutual funds are not insured, there are many safeguards in place to ensure that no one runs off with your money. The NAV is the price of one unit in a mutual fund. Mutual funds are not insured.
Load funds charge sales commissions.