(a) A financial institution having its principal office in this state shall be taxed as a business corporation organized and existing under the laws of this state.
(b)
(1) A financial institution having its principal office outside this state but doing business in this state shall be taxed as a foreign business corporation doing business in this state.
(2) However, this subsection is not intended to recognize the right of a foreign financial institution to conduct any business activities in this state except to the extent and under the conditions permitted by Acts 1953, No. 559, §§ 1-8 [unconstitutional] and any other applicable laws of this state.