What is the meaning of Open-End Fund?

This is the standard municipal bond fund. It has no fixed number of bonds in its portfolio. Rather it buys issues as investors buy shares in the fund, sells issues as investors redeem shares. The tax-free dividend is dependent on a pro-rata share of the interest earned, and this varies as the income of the portfolio varies. The fund managers guarantee to buy back shares at their Net Asset Value, the market value of all the bonds in their portfolio as determined at the close of each business day. This NAV per share can be more or less than the original purchase price.' Open-End Fund's have no maturity date so ultimately they must be sold to return principal.