It seems like when the question says there are more sellers than buyer...

Exam candidates know that closed-end fund shares trade among investors on the secondary market. Does that mean for closed-end funds the imbalance of buying and selling interest does determine the NAV?

No. The Net Asset Value for either an open-end or closed-end fund is the difference between the assets of the securities portfolio, minus any liabilities, divided by the outstanding shares. Open-end funds don’t borrow a lot of money, so their liabilities are minimal. At the end of each market session, the value of all stocks and bonds in the portfolio are revalued. Those, plus all the cash the portfolio has generated, are the assets. The liabilities are the amounts borrowed short-term, perhaps to pay investors who redeem shares. Take the assets, minus the liabilities, and divide those net assets by the number of outstanding shares.

That is the new NAV for the fund.

Only now are shares redeemed at that price or sold to investors at a price based on this new NAV. The transfer agent is merely turning cash into shares, or shares into cash, based on this new Net Asset Value per share. Investors’ shares are not being traded among investors.

The NAV is calculated the same way, and only once a day, for a closed-end fund. The shares trade throughout the day, at a market price that could be above or below the NAV.