Which term best describes a property interest that automatically transfers to the owner's estate upon death?

The term that best describes a property interest that automatically transfers to the owner's estate upon death is reversionary interest. A reversionary interest occurs when a property owner transfers some interest in a property to another party but retains the right for the property to revert back to them or their estate after a certain event, such as the death of the owner or the completion of a lease term.

This means that upon the owner's death, ownership of the property goes back to their estate, ensuring that the estate has claim over the property without the need for formal probate processes or additional actions.

In contrast, fee simple represents the most complete interest in property, but it doesn’t inherently include a transfer upon death to the owner's estate. Joint tenancy allows for automatic transfer to the surviving joint tenants rather than the estate. Tenants in common provide for a shared ownership structure, but without automatic transfer to the deceased's estate, as each tenant has their own share of ownership that they can pass on independently. Thus, reversionary interest specifically captures the automatic transfer aspect upon death, making it the correct answer.