Wis. Stat. § 611.34: Corporate repurchase of shares.

No stock corporation may repurchase any of its own shares within 5 years after initial issuance of the certificate of authority, except pursuant to a plan for the repurchase which has been approved by the commissioner. After 5 years a stock corporation may repurchase its own shares under ss. 180.0631, 180.0640, and 180.1708 (2), but within 10 days after the end of any month in which it purchases more than one percent of any class of its outstanding shares the corporation shall report the price and the names of the registered shareholders from whom the shares are acquired and of any other persons beneficially interested, so far as the latter are known to the corporation. The corporation shall make a like report within 10 days after the end of any 3-month period in which it purchases more than 2 percent of any class of its outstanding shares or within 10 days after the end of any 12-month period in which it purchases more than 5 percent of any class of its outstanding shares.