Wis. Stat. § 114.78: Tax exemption.

The exercise of the powers granted by this subchapter will be in all respects for the benefit of the people of this state and for the increase of their commerce, welfare, and prosperity, and, as the undertaking of the authority’s powers and duties under this subchapter will constitute the performance of an essential public function, the authority shall not be required to pay any taxes or assessments upon or in respect to any property acquired or used by the authority under this subchapter and the authority’s income therefrom shall at all times be free from taxation of every kind by the state and by political subdivisions of the state.