A mutual fund may accept applications even after the cut-off time, but the investor will get the NAV of the next business day. Further, the cut-off time rules apply for redemptions too.A mutual fund scheme's NAV is calculated and declared at the end of each market day, after the market has closed. This is because the prices of the stocks and other securities in the fund's portfolio constantly fluctuate throughout the day, making it difficult to calculate NAV during market hours. By calculating the NAV after market closing, the fund can use the final closing prices of all its holdings to determine the most accurate value of its assets.