Oklahoma constitution
Article IX: corporations
Section 41

No trust company, or bank or banking company shall own, hold, or control, in any manner whatever, the stock of any other trust company or bank or banking company, except such stock as may be pledged in good faith to secure bona fide indebtedness, acquired upon foreclosure, execution sale, or otherwise for the satisfaction of debt; and such stock shall be disposed of in the time and manner hereinbefore provided.