What principle allows the ownership interest to revert to the surviving co-owners when a co-owner dies?

The principle that allows the ownership interest to revert to the surviving co-owners when a co-owner dies is known as the right of survivorship. This legal concept is a defining characteristic of joint tenancy, where each owner's share automatically transfers to the remaining co-owners upon their death. This means that the deceased co-owner's share does not become part of their estate or go to their heirs, but instead is immediately and automatically distributed among the surviving joint tenants.

In scenarios where joint tenants hold property together, the right of survivorship ensures a seamless transition of ownership interests, preventing the complications that can arise when property is passed through wills or probate. This principle fosters financial stability and continuity among surviving co-owners, clearly defining their rights and reducing potential conflicts regarding property interests after a co-owner's death.

This is in contrast to tenancy in common, where co-owners each have an individual share of the property that can be transferred to heirs upon death, and leasehold interest, which pertains to a temporary right to use and occupy property but does not involve ownership in the traditional sense. Thus, the correct answer is grounded in the nature of joint tenancy and the legal concept of the right of survivorship that governs it.