North Dakota Constitution Art. XII, § 16

Any combination between individuals, corporations, associations, or either having for its object or effect the controlling of the price of any product of the soil or any article of manufacture of commerce, or the cost of exchange or transportation, is prohibited and hereby declared unlawful and against public policy; and any and all franchises heretofore granted or extended, or that may hereafter be granted or extended in this state, whenever the owner or owners thereof violate this article shall be deemed annulled and become void.