432A.6  Computation of tax on ocean marine insurance profit.
  In determining the amount of the tax imposed by this chapter, the taxable underwriting profit of such insurer on such ocean marine insurance business written within this state, shall be ascertained as follows:
  1.  In the case of every such insurer which has written any such business within this state during three calendar years immediately preceding the year in which such taxes were payable, the taxable underwriting profit shall be determined by adding or subtracting, as the case may be, the underwriting profit or loss on all such insurance written within the United States, ascertained as hereinbefore provided, for each of such three years and dividing by three.
  2.  In the case of every such insurer other than as specified in subsection 1 such taxable underwriting profit, if any, shall be the underwriting profit, if any, on such ocean marine insurance business written within this state during the taxable year, ascertained as hereinbefore provided, but after such insurer has written such ocean marine insurance business within this state during three calendar years, an adjustment shall be made on the three-year average basis by ascertaining the amount of tax payable in accordance with subsection 1.
[C75, 77, 79, 81, §432A.6]