Ala. Code § 40-21-6
Insofar as the other evidence and information adduced before said department does not make it appear to said department improper or unjust for it to do so, the said department shall, in fixing the true value of the entire property, tangible and intangible, of any company, corporation, association or individual embraced within the provisions of this title, consider as a factor the average net earnings, averaged over a period of five years, and also take as a basis therefor the aggregate average market value or true value for the preceding year of all its shares of stock and add thereto the average market or true value for the preceding year of its entire indebtedness secured by any mortgage, lien or other charge upon its property and assets, and the sum or sums so produced shall be treated and considered a factor in ascertaining the true value of said entire property, tangible and intangible, for purpose of ad valorem taxation. The department may likewise consider the value of the individual units and items of property and the sum of the values of such units or items.
Ala. Code § 40-21-6 (1975)