No person shall, without the prior approval of the commissioner, acting directly or indirectly or through or in concert with one or more persons:
a. Obtain or exercise control of a capital stock state association; or
b. Acquire beneficial ownership or control of any voting shares of a capital stock state association, if, after the acquisition, the person would beneficially own or control more than 25% of the then-outstanding voting share of the capital stock state association.