Real property in this State belonging to a resident transferor is subject to the Inheritance Tax Law. Real property outside the State belonging to a resident transferor is not subject to the law. If, however, a resident transferor owning real property situated outside the State has entered into an executory contract for its sale, the right of the transferor, his estate or heir to the proceeds of the sale will be treated as subject to the law should the state in which the property is situated not subject the property to its own inheritance or estate tax law, either on an application of the so-called "doctrine of equitable conversion" or for any other reason.
Cal. Code Regs. Tit. 18, § 13303.1
Note: Reference: Sections 13303- 13305, Revenue and Taxation Code.