A reversion in property law is a future interest that is retained by the grantor after the conveyance of an estate of a lesser quantum that he has (such as the owner of a fee simple granting a life estate or a leasehold estate). Once the lesser estate comes to an end (the lease expires or the life estate tenant dies), the property automatically reverts (hence reversion) back to the grantor. Unlike some other future interests, reversions have always been fully alienable ('sellable').