Unless a bank owns at least eighty percent of the stock of the agricultural credit corporation or livestock loan company, it may not obligate more than twenty percent of its capital stock and surplus for those purposes

— under GENERAL POWERS OF BANKS.

Under no circumstances may a bank obligate more than twenty percent of its capital stock and surplus and undivided profits for that purpose. Any agricultural credit corporation or livestock loan company, or its affiliate, has the same privileges as a state chartered bank or trust company provided in §