A closed-end fund (CEF) is a fund that raises capital by issuing a fixed number of shares which are not redeemable, and then invest that capital in financial assets such as stocks and bonds. Unlike open-end funds, new shares in a closed-end fund are not created by managers to meet demand from investors. Instead, the shares can be purchased and sold only in the market, which is the original design of the mutual fund, which predates open-end mutual funds but offers the same actively-managed pooled investments.

In the United States, closed-end funds sold publicly must be registered under both the Securities Act of 1933 and the Investment Company Act of 1940.

Closed-end funds are usually listed on a recognized stock exchange and can be bought and sold on that exchange. The price per share is determined by the market and is usually different from the underlying value or net asset value (NAV) per share of the investments held by the fund. The price is said to be at a discount or premium to the NAV when it is below or above the NAV, respectively.

A premium might be caused by the market's confidence in the investment managers' ability or the underlying securities to produce above-market returns. A discount might reflect the charges to be deducted from the fund in future by the managers, uncertainty from high amounts of leverage, concerns related to liquidity or lack of investor confidence in the underlying securities.

In the United States, closed-end funds are referred to under the law as closed-end companies and form one of three SEC-recognized types of investment companies along with mutual funds and unit investment trusts.