Wis. Stat. § 221.0310

A bank that has loans secured by real estate mortgages may, with the approval of the division, sell all or any portion of the loans to the Federal National Mortgage Association, or any successor to that association. In connection with this sale of loans, the bank may make payments of any required capital contributions in the nature of subscriptions for stock of the Federal National Mortgage Association or any successor to that association, may receive stock evidencing these capital contributions and may hold or dispose of this stock.