Okla. Const. art. XIV, § 2

Classification of loans and lenders - Licenses - Maximum rates of interest. The Legislature shall have authority to classify loans and lenders, license and regulate lenders, define interest and fix maximum rates of interest; provided, however, in the absence of legislation fixing maximum rates of interest, all contracts for a greater rate of interest than ten percent(10%) per annum shall be deemed usurious; provided, further, that in contracts where no rate of interest is agreed upon, the rate shall not exceed six percent (6%) per annum. Amended by State Question No. 454, Legislative Referendum No. 167, adopted at election held Sept. 17, 1968.