Joint tenant

A concurrent estate or co-tenancy is a concept in property law which describes the various ways in which property is owned by more than one person at a time. If more than one person owns the same property, they are referred to as co-owners. If more than one person leases the same property, they are called co-tenants or joint tenants. Most common law jurisdictions recognize tenancies in common and joint tenancies, and some also recognize tenancies by the entirety. Many jurisdictions refer to a joint tenancy as a joint tenancy with right of survivorship, and a few U.S. states treat the phrase joint tenancy as synonymous with a tenancy in common.

The type of ownership determines the rights of the parties to sell their interest in the property to others, to will the property to their devisees, or to sever their joint ownership of the property. Just as each of these affords a different set of rights and responsibilities to the co-owners of property, each requires a different set of conditions to exist.

Law can vary from place to place, and the following general discussion will not be applicable in its entirety to all jurisdictions.

Under the common law, Co-owners share a number of rights by default:

Co-owners generally do not have any obligation to contribute to any costs of improving the property. If one co-owner adds a feature that enhances the value of the property, that co-owner has no right to demand that any others share the cost of adding that feature – even if other co-owners reap greater profits from the property because of it. However, at partition, a co-owner is entitled to recover the value added by his or her improvements of the property if the "improvements" resulted in an increase in property value. Conversely, if the co-owner's "improvements" decrease the value of the property, the co-owner is responsible for the decrease. In an Australian case, the High Court said that the costs of repairing by one co-owner must be taken into account on the partition or final distribution (i.e. sale) of the property.

Furthermore, each co-owner can independently encumber the co-owner's own share in the property by taking out a mortgage on that share (although this may effectively convert a joint tenancy to a tenancy in common, as described below); other co-owners have no obligation to help pay a mortgage that only runs to another owner's share of the property, and the mortgagee can only foreclose on that mortgagor's share. Bank loans secured by mortgages on individual shares of co-owned property are one of the most rapidly expanding areas in the mortgage lending industry.

...
Wikipedia