(a) In general
For purposes of this subchapter, the notional shipping income of an electing corporation shall be the sum of the amounts determined under subsection (b) for each qualifying vessel operated by such electing corporation.

(b) Amounts

(1) In general
For purposes of subsection (a), the amount of notional shipping income of an electing corporation for each qualifying vessel for the taxable year shall equal the product of—

(A) the daily notional shipping income, and

(B) the number of days during the taxable year that the electing corporation operated such vessel as a qualifying vessel in United States foreign trade.

(2) Treatment of vessels the income from which is not otherwise subject to tax
In the case of a qualifying vessel any of the income from which is not included in gross income by reason of section 883 or otherwise, the amount of notional shipping income from such vessel for the taxable year shall be the amount which bears the same ratio to such shipping income (determined without regard to this paragraph) as the gross income from the operation of such vessel in the United States foreign trade bears to the sum of such gross income and the income so excluded.

(c) Daily notional shipping income
For purposes of subsection (b), the daily notional shipping income from the operation of a qualifying vessel is—

(1) 40 cents for each 100 tons of so much of the net tonnage of the vessel as does not exceed 25,000 net tons, and

(2) 20 cents for each 100 tons of so much of the net tonnage of the vessel as exceeds 25,000 net tons.

(d) Multiple operators of vessel
If for any period 2 or more persons are operators of a qualifying vessel, the notional shipping income from the operation of such vessel for such period shall be allocated among such persons on the basis of their respective ownership, charter, and operating agreement interests in such vessel or on such other basis as the Secretary may prescribe by regulations.