Okla. Stat. tit. 6, § 706

A. Transfer of shares. The shares of stock of a bank or trust company shall be deemed personal property and shall be transferred on the books of the bank or trust company, in such manner as the bylaws may prescribe but no stock shall be transferred on the books of any bank or trust company where the registered holder thereof is indebted to the bank or trust company for any matured and unpaid obligations. The shares of stock of a stockholder indebted to the bank or trust company, as provided herein, may be transferred or any claims of the bank or trust company, as herein defined, may be waived at any time by written consent of the bank or trust company, executed by an officer other than the borrowing stockholder. B. Lending on stock prohibited. It shall be unlawful for any bank or trust company to loan its funds to any stockholder, on its stock or its holding company stock as collateral security; provided, that any bank or trust company may hold its stock to secure the indebtedness previously in good faith contracted. C. Purchase of treasury stock. With the approval of the Commissioner and subject to the conditions as the Commissioner may prescribe, a bank may purchase its own stock as treasury stock.