Wis. Stat. § 221.0307
A bank may, with the approval of the division and by action of the bank's board of directors, acquire and hold the stock of any state or federal agency or of any similar institution approved by the division. A bank that intends to make such an investment shall give the division written notice of its intention. The division may disallow the investment if it finds that the bank is in an unsafe or unsound condition or that the transaction would be an unsafe or unsound investment for the bank. The division shall have 30 days after the date on which notice is received to issue a prohibition under this section. The division may extend the time for issuing the prohibition to 30 additional days if the division notifies the bank before the initial 30-day period expires that the division is extending the time limit.
Wis. Stat. § 221.0307