Definition of 'Defeased Securities'
Securities that have been secured by another asset, such as cash or a cash equivalent, by the debt-issuing firm. Firms that have created defeased securities, which are typically bonds, will have sufficient cash set aside for retirement of the debt upon maturity.
Investopedia explains 'Defeased Securities'
For example, the U.S. government could place the funds necessary to pay off a series of Treasury bonds in a trust account specifically created to pay the outstanding bonds upon maturity. The government sets aside these funds to ensure that it has enough cash to pay its bonds when they are due. Commonly, defeased securities are retractable.
Securities than can be defeased will often carry a lower yield than comparable securities, as the option to retire the debt early favors the issuer and caps the potential investment return for the bondholder. However, for a risk averse investor, this feature proves beneficial because it lowers the default risk of the security.