In the context of security over an asset, the process by which the mortgagor's rights in the secured asset are extinguished (that is, the mortgagor's equity of redemption is extinguished) and that asset becomes vested in the mortgagee. The mortgagee becomes the absolute owner of the asset and may then sell it free of the mortgagor's rights (including its equity of redemption), and free of the rights of any lower ranking security-holders. A mortgagee's right to foreclose arises once the liabilities secured by the mortgage have become repayable. The right is available to the holder of a legal mortgage and, in certain circumstances, the holder of an equitable mortgage but not to the holder of a pledge or a charge. For more information, see Practice notes, Enforcing security: overview: Foreclosure and Mortgages and charges over land: Foreclosure.

In the context of competition law, the closing of potential opportunities to actual or potential competitors by means of exclusivity arrangements (so that, for example, a party who agrees to purchase all his requirements for products of a particular range from one supplier denies other suppliers the opportunity of supplying him). There will be foreclosure where such arrangements make it difficult to enter the market and where there are no concrete possibilities for bypassing those arrangements, for example, by acquiring or using other distribution formats.