Realising the value of your investment in a financial instrument by redeeming it — giving it back to the issuer for cancellation against payment of its face value, redemption amount, or net asset value — rather than selling it in the secondary market.

Requires the instrument in question to have reached its maturity, or an optional redemption date, or be the sort of thing (like an investment in an open-ended investment company) with periodic redemption rights. Some sorts of instruments (e.g. shares) don't ever do that, so all you can do to liquidate your investment is to sell them.

See also