Cal. Code Regs. tit. 2 § 1138.18
If a decedent, having property with a situs in California, leaves property having a situs in a state other than California, the maximum state death tax credit shall be multiplied by the percentage which the gross value of property having a situs in California bears to the gross value of the entire estate subject to federal estate tax. The product of the calculation shall be the portion of the maximum state death tax credit which is attributable to property having a situs in California. The property having a situs in the other state, whether or not or to what extent the property is taxed in that state, will be ignored for purposes of the California tax.
Cal. Code Regs. Tit. 2, § 1138.18
Note: Authority cited: Section 14103, Revenue and Taxation Code. Reference: Section 13304, Revenue and Taxation Code.