The
mnemonic PITT is used for the four unities here: Possession, Interest, Time, &
Title. ; Unity of time : Interest must be acquired by both tenants at the same time. ::At common law, the "time" requirement could be satisfied only by using a "
straw man" to create a joint tenancy. The party creating the joint tenancy would have to convey title to a straw man, who would then transfer title to the two parties as joint tenants. ; Unity of title : The interests held by the co-owners must arise out of the same instrument (i.e., written contract, deed of conveyance or assignment, etc.). ; Unity of interest : Both tenants must have the same interest in the property. ::This means that the joint tenants must have the same type of interest. For example, if X and Y acquire a joint tenancy, both X and Y's interests must be in
fee simple absolute. If, for example, X has a fee simple absolute and Y has a
life estate, there is no unity of interest. ; Unity of possession : Both tenants must have the right to possess the whole property. ::This is a joint right: if they agree between themselves to possess different parts, that will not affect their joint right (as against a landlord or other third party) to possess the whole. If any of the four unities is broken and it is not a joint tenancy, the ownership reverts to a
tenancy in common. The unique aspect of a joint tenancy is that as the joint tenancy owners die, their shares accrue to the surviving owner(s) so that, eventually, the entire share is held by one person. Realism and Formalism in the Severance of Joint Tenancies This is because, for the purpose of the property interest, joint owners are regarded as a single legal entity. == A fifth unity ==