The explanations of NAV I see are that it is the value of the fund, less liabilities, divided by the number of shares. The fund's expenses come out of the fund's net assets.
Most funds have different classes, with different expense ratios. But all the classes come from the same pool of securities that make up the fund.
It seems like there must be something else going on here, as that appears contradictory. If different classes come from the same set of assets, then should't the NAV of each class be the same? But if the NAV was the same, then how could the higher expense ratio classes be charging higher expenses? Doesn't their NAV need to grow less than lower expense ratio funds?