Wis. Stat. § 214.63
The executed merger agreement, together, in the case of a stock financial institution, with a certified copy of the minutes of the meeting of stockholders of each merging stock financial institution approving the merger agreement, shall be filed with the division. The division shall issue to the resulting savings bank a certificate of merger, setting forth the name of each merging financial institution, the name of the resulting savings bank and the date on which the division approves the articles of incorporation and bylaws of the resulting savings bank. The merger takes effect on the date of the recording of the certificate or a later date if the certificate provides for a different date. Recording shall be completed in the same manner as required for savings bank articles of incorporation, in each county in which the home office of any of the merging financial institutions was located and in the county in which the home office of the resulting savings bank is located. The certificate shall be conclusive evidence of the merger and of the correctness of the merger proceedings except against this state.
Wis. Stat. § 214.63