Open-end funds are obligated to redeem investor's shares at net asset value, and thus must keep cash or cash-equivalent securities on hand in order to meet potential redemptions. Closed-end funds do not need the cash reserves because there are no redemptions for closed-end funds. Investors in closed-end funds sell their shares when they wish to cash out
Why can closed-end funds sell at prices that differ from net asset value while open-end funds do not?
All mutual funds fall into one of two broad categories: open-end funds and closed-end funds. Most mutual funds are open-end. The reason why these funds are called "open-end" is because there is no limit to the number of new shares that they can issue. New and existing shareholders may add as much money to the fund as they want and the fund will simply issue new shares to them. Open-end funds also redeem, or buy back, shares from shareholders. In order to determine the value of a share in an open-end fund at any time, a number called the Net Asset Value (described below) is used. You purchase shares in open-end mutual funds from the mutual fund itself or one of its agents; they are not traded on exchanges.
Closed-end funds behave more like stock than open-end funds; that is to say, closed-end funds issue a fixed number of shares to the public in an initial public offering, after which time shares in the fund are bought and sold on a stock exchange. Unlike open-end funds, closed-end funds are not obligated to issue new shares or redeem outstanding shares. The price of a share in a closed-end fund is...