Wis. Stat. § 72.02
An estate tax is imposed upon the transfer of all property that is subject to a federal estate tax and that has a taxable situs in this state. The tax imposed is equal to the federal credit against the federal estate tax as finally determined. If only a portion of a decedent's property has a taxable situs in this state, the tax imposed is the amount obtained by multiplying the federal credit by a fraction the numerator of which is the value of the decedent's estate that has a taxable situs in this state and the denominator of which is the total value of the property in the estate that qualifies for the federal credit.
Wis. Stat. § 72.02
The gross estate for purposes of calculating the estate tax is the taxable estate as determined under federal law. The statutes do not authorize the Department of Revenue to add gifts made in contemplation of death to the federal taxable estate when calculating the estate tax. The amount of estate tax is determined by the federal credit for state death taxes provided under federal law. Any construction that results in a calculation of the estate tax that is not equal to the federal tax credit for state death taxes is inconsistent with the plain language of this section. DOR v. Estate of Schweitzer, 2008 WI App 2, 307 Wis. 2d 298, 744 N.W.2d 861, 06-0984. Wisconsin's New Estate Tax. Wilcox. Wis. Law. Dec. 2001. Time Runs Out on Wisconsin's Estate Tax. Reineke & Botham. Wis. Law. Dec. 2007.