Wisconsin Department of Revenue v. Milwaukee Mutual Insurance Co.

This appeal involves the attempted imposition of Wisconsin’s corporation franchise tax on income earned before the tax became effective. We conclude that the taxing statute’s use of the terms “federal taxable income,” “net income,” and “federal income tax” creates ambiguity, and affirm rejection of the attempted taxation in this case.

Section 71.01, Stats., provides in part:(2) Franchise tax on corporations. . . . The tax imposed by this subsection on insurance companies subject to taxation under this chapter . . . shall be based on net income computed under sub. (4), and no other provision of…