Okla. Stat. tit. 36 § 624.1
If, by the laws of any state other than this state, or by the action of any public official of another state, any insurer or company, as defined in Section 624 of this Code, organized or domiciled in this state, shall be required to pay taxes for the privilege of doing business in such other state, and such amounts are imposed or assessed so that the taxes which are or would be imposed against Oklahoma domestic insurance companies are greater than those taxes required of insurers organized or domiciled in such other states, to the extent such amounts are legally due to such other states, an insurer or company organized or domiciled in this state may claim a credit against the tax payable pursuant to this article for any calendar year prior to 1989 of a sum not to exceed one hundred percent (100%) of such amount. Provided, for the tax attributed to premiums collected prior to July 1, 1988, the credit shall not be greater than the tax payable for such premiums; for the tax attributed to premiums collected on or after July 1, 1988 through December 31, 1988, the credit authorized by this section and the investment credit authorized by Section 625 of this title shall not reduce the tax payable for such premiums to less than one percent (1%).
Beginning with the taxes payable for calendar year 1989, the premium tax levied by Section 624 of this title shall not be reduced by the credit provided for in this section.
Okla. Stat. tit. 36, § 624.1