NAV means Net Asset Value; it represents the current value of our mutual fund units at which they are trading. It is similar to CMP of shares in stock markets
NAV is measure only useful for open traded mutual funds, as buying can be done at desired NAV value.
Like shares NAV changes based on the market conditions and securities that mutual fund company is invested. It continuously alters on the intraday during trading hours during market working days.
The NAV during initial fund issue is the base value of that fund. The base value NAV is allotted on company preference.
But unlike in shares the NAV value is not affected by public fund holders (Demand to fund), say that even large investor response had come to fund its value (NAV) cannot increase.