Investment returns on a unit trust fund depend on the following:

-Returns from the financial markets;
-The type of assets within the unit trust portfolio; and
-The management skills of the portfolio managers.

The value of shares, bonds and other asset classes are determined by financial markets and can rise or fall over time.
In general, equity-based unit trusts provide the highest potential return, followed by bond or income funds and finally money market funds. In addition, the level of investment return is generally related to the level of risk incurred i.e. the higher the potential risk, the greater the potential return.