Wis. Stat. § 226.05: Bank deposits by nonresidents, taxation evidence.

The making and maintaining of deposits and checking or other accounts by a nonresident of this state or by a foreign corporation in any bank, either state or national, or in any trust company in this state, shall not be considered as doing business or acquiring, holding or disposing of property in this state, nor considered a factor in determining whether such person or corporation is doing business in this state, or in determining the situs of the property or income of such corporation or person for taxation purposes.