Wis. Stat. § 224.03: Banking, unlawful, without charter; penalty.

It shall be unlawful for any person, partnership, association, or corporation to do a banking business without having been regularly organized and chartered as a national bank, a state bank or a trust company bank. Any person or persons violating any of the provisions of this section, either individually or as an interested party in any partnership, association, or corporation shall be guilty of a misdemeanor and on conviction thereof shall be fined not less than $300 nor more than $1,000 or imprisoned in the county jail for not less than 60 days nor more than one year or both.