Ala. Code § 11-20-47

The corporation, all properties at any time owned by it and income therefrom of the corporation, all bonds issued by the corporation and the income therefrom, conveyances by or to the corporation and leases and mortgages by or to the corporation shall be exempt from all taxation in the State of Alabama. No license or excise tax may be imposed on any corporation in respect of the privilege of engaging in any of the activities authorized by this article.