Most mutual funds are open-end fundss. This means that at the end of every day, the investment management company sponsoring the fund issues new shares to investors and buys back shares from investors wishing to leave the fund. A mutual fund can also be a closed-end fund. The sponsor of a closed-end fund registers and issues a fixed number of shares at the initial offering, similar to a common stock. Investors then can buy or sell these shares through a stock exchange. The sponsor does not redeem or issue shares after a closed-end fund is launched, so the investor must trade them through a broker.
Mutual funds can invest in many different kinds of securities. The most common are cash, stock, and bonds, but there are hundreds of sub-categories. Stock funds, for instance, can invest primarily in the shares of a particular industry, such as high technology or utilities. These are known as sector funds. Bond funds can vary according to risk (high yield or junk bonds, investment-grade corporate bonds), type of issuers (government agencies, corporations, or municipalities), or maturity of the bonds (short or long term). Both stock and bond funds can invest in primarily US securities (domestic funds), both US and foreign securities (global funds), or primarily foreign securities (international funds). By law, mutual funds cannot invest in commodities and their derivatives or in real estate. (However, there do exist real estate investment trusts, or REITs, which invest solely in real estate or mortgages, and mutual funds are allowed to hold shares in REITs.) A mutual fund may restrict itself in other ways. These restrictions, permissions, and policies are found in the prospectus, which every open-end mutual fund must make available to a potential investor before accepting his or her money.
Most mutual funds' investment portfolios are continually adjusted under the supervision of a professional manager, who forecasts the future performance of investments appropriate for the fund and chooses the ones which he or she believes will most closely match the fund's stated investment objective. This is called active management, in contrast to indexing, in which a fund's assets are managed to closely approximate the performance of a particular published index. Because the composition of an index changes less frequently than the condition of the market, an index fund manager makes fewer trades, on average, than does an active fund manager. For this reason, index funds generally have lower expenses than actively-managed funds, and typically incur fewer capital gains which must be passed on to shareholders.
Mutual funds are corporations under US law, but they are subject to a special set of regulatory, accounting, and tax rules. Unlike most other types of corporations, they are not taxed on their income as long as they distribute substantially all of it to their shareholders. Also, the type of income they earn is often unchanged as it passes through to the shareholders. Mutual fund distributions of tax-free municipal bond income are also tax-free to the shareholder. Taxable distributions can either be ordinary income or capital gains, depending on how the fund earned it.
You can buy many mutual funds directly from the fund sponsor. These are called "no-load" funds, because the issuer does not charge a sales commission. Some discount brokers will sell no-load funds, some for a flat transaction fee, some for no fee at all. Load funds are sold through intermediaries such as brokers, financial planners, and other types of registered representatives who charge a commission for their services.
Picking a mutual fund from among the thousands offered is not easy. The following is just a rough guide, with some common pitfalls.