§ 89 Sole Ownership and Co-ownership
As a general rule a right is owned by one person only at a time, but duplicate ownership is perfectly possible. Two or more persons may at the same time have the same right vested in them. This may happen in several distinct ways, but the simplest and most obvious case is that of co-ownership. Partners, for example, are co-owners of the chattels which constitute their stock in trade, of the lease of the premises on which their business is conducted, and of the debts owing to them by their customers. It is not correct to say that a right owned by co-owners is divided between them, each of them owning a separate part. The right is an undivided unity, which is vested at the same time in more than one person. If two partners have at their bank a credit balance of 1000l., there is one debt of 1000l. owing by the bank to both of them at once, not two separate debts of 500l. due to each of them individually. Each partner is entitled to the whole sum, just as each would owe to the bank the whole of the firm’s overdraft. The several ownership of a part is a different thing from the co-ownership of the whole. So soon as each of two co-owners begins to own a part of the right instead of the whole of it, the co-ownership has been dissolved into sole ownership by the process known as partition. Co-ownership involves the undivided integrity of the right owned.
Co-ownership, like all other forms of duplicate ownership, is possible only so far as the law makes provision for harmonising in some way the conflicting claims of the different owners inter se. In the case of co-owners the title of the one is rendered consistent with that of the other by the existence of reciprocal obligations of restricted use and enjoyment.
Co-ownership may assume different forms by virtue of the different incidents attached to it by law. Its two chief kinds in English law are distinguished as ownership in common and joint ownership. The most important difference between these relates to the effect of the death of one of the co-owners. In ownership in common the right of a dead man descends to his successors like any other inheritable right. But on the death of one of two joint owners his ownership dies with him, and the survivor becomes the sole owner by virtue of this right of survivorship or jus accrescendi.