Defeasible estate

A defeasible estate is created when a grantor transfers land conditionally. Upon the happening of the event or condition stated by the grantor, the transfer may be void or at least subject to annulment. (An estate not subject to such conditions is called an indefeasible estate.) Historically, the common law has frowned on the use of defeasible estates as it interferes with the owners' enjoyment of their property and as such has made it difficult to create a valid future interest. Unless a defeasible estate is clearly intended, modern courts will construe the language against this type of estate. Three types of defeasible estates are the fee simple determinable, the fee simple subject to an executory limitation or interest, and the fee simple subject to a condition subsequent. A life estate may also be defeasible.

Because a defeasible estate always grants less than a full fee simple, a defeasible estate will always create one or more future interests.