The performance of a particular scheme of a mutual fund is denoted by Net Asset Value (NAV).
NAV is the market value of the securities held by the scheme. Since market value of securities changes every day, NAV of a scheme also varies on day to day basis.
It is calculated as follows : Take the current market value of the fund's net assets (securities held by the fund minus any liabilities) and divide by the number of units outstanding. Thus, if a fund has total net assets of ₹ 100 crores and 5 crore units, the NAV is ₹ 20 per unit. (Fund liabilities include items such as fees owed to investment managers.)
Open-ended schemes declare the NAV at the end of every business day.