Co-ownership can be a joint tenancy and tenancy in common. With a joint tenancy, this is collective ownership and makes it so there is unity of ownership amongst one or more persons. Any sale or disposal of the property has to be done collectively with the unity of ownership. In this case, the initial purchase involved Harry, Ron, and Hermione all of which contributed equally to the purchase price of the property. If the law regarded them as joint tenants this would mean that Harry, Ron, and Hermione could not sell their share of the property to anyone else or leave it in a will to anyone else.
Joint tenancy agreements create the right of survivorship. Under this doctrine when one of the joint tenants dies their share in the property is divided between the surviving tenants. In this situation, this would mean that when Harry died his share would have been split between Ron and Hermione. As joint tenants, the legal title can only be dealt with as a whole. Joint tenancies are classed as unseverable. Although the joint tenancy is not severable Ron can sell his interest to Hermione as she is a joint tenant with him. None of the parties can force others to sell the property. It must be a unilateral decision as joint tenancy insists on the unity of title. When Ron sold his share of the property to Hermione if he did not expressly surrender his legal ownership in the property Hermione would not be able to sell the restaurant without Ron’s agreement.
Co-ownership generally assumes that the relationship is a joint tenancy unless there have been words of severance or when it is one of the three special cases where the owner is covered by equity. Under equity one of the special cases that are listed is where the co-owners are business partners. The notion behind treating business partners as tenants in common is because it is not appropriate to have rights of survivorship in business dealings. A tenancy in common creates individual ownership in the shares of the property but can only be recognized in equity or through severance.