The Registrar General requires instruments presented for registration to state expressly whether co-owners are to take as joint tenants or tenants in common. The benefits accruing from this form of co-ownership, in terms of smooth transition of ownership, make joint tenancies an attractive arrangement for couples purchasing property together. This convenience is reflected in the high proportion of co-owners preferring to adopt this arrangement. The Land Titles Office estimates that in NSW joint tenancies outnumber tenancies in common by a factor of 11 to 1. A joint tenancy may be severed during the lifetime of the joint tenants.
Severance operates to convert the interest held as joint tenant into one held as tenant in common.
At common law there are three ways in which a joint tenancy can be severed. Each one is at liberty to dispose of his own interest in such manner as to sever it from the joint fund - losing, of course, at the same time, his own right of survivorship. And, in the third place , there may be a severance by any course of dealing sufficient to intimate that the interests of all were mutually treated as constituting a tenancy in common. When the severance depends on an inference of this kind without any express act of severance, it will not suffice to rely on an intention, with respect to the particular share, declared only behind the backs of the other persons interested. There are several reasons why co-owners may wish to sever the joint tenancy.