(1)
General rule
Subject to paragraph (2), each item of loss, deduction (other than for interest expense), or credit of any taxpayer with respect to any activity the income from which is excluded from gross income under this section shall be disallowed.
(3)
Interest
(A)
In general
Except as provided in subparagraph (B), the interest expense of an electing corporation shall be disallowed in the ratio that the fair market value of such corporation’s qualifying vessels bears to the fair market value of such corporation’s total assets.
(B)
Electing group
In the case of a corporation which is a member of an electing group, the interest expense of such corporation shall be disallowed in the ratio that the fair market value of such corporation’s qualifying vessels bears to the fair market value of the electing groups total assets.