Okla. Const. art. XXII, § 2

No corporation shall be created or licensed in this State for the purpose of buying, acquiring, trading, or dealing in real estate other than real estate located in incorporated cities and towns and as additions thereto; nor shall any corporation doing business in this State buy, acquire, trade, or deal in real estate for any purpose except such as may be located in such towns and cities and as additions to such towns and cities, and further except such as shall be necessary and proper for carrying on the business for which it was chartered or licensed; and provided further that under limitations prescribed by the legislature, any corporation may acquire real estate for lease or sale to any other corporation, if such latter corporation could have legally acquired the same in the first instance; nor shall any corporation be created or licensed to do business in this State for the purpose of acting as agent in buying and selling or leasing land for agricultural purposes; provided, however, that corporations shall not be precluded from taking mortgages on real estate to secure loans or debts, or from acquiring title thereto upon foreclosure of such mortgages or in the collection of debts, conditioned that such corporation or corporations shall not hold such real estate for a longer period than seven (7) years after acquiring such title; and provided, further, that this Section shall not apply to trust companies taking only the naked title to real estate in this State as a trustee, to be held solely as security for indebtedness pursuant to such trust; and provided, further, that no public service corporation shall hold any land, or the title thereof, in any way whatever in this State, except as the same shall be necessary for the transaction and operation of its business as such public service corporation.