(a) The term entire net income means total net income from all sources, which is the same as the taxable income which the taxpayer is required to report to the United States Department of the Treasury for purposes of the Federal income tax imposed by chapter one of the Internal Revenue Code with the adjustments required by sections 18-2.3, 18-2.4 and 18-2.5 of this Subpart.

(b) Federal taxable income means taxable income as defined in section 63 of the Internal Revenue Code, and is the starting point in computing entire net income.

(c) Each corporation included in a Federal consolidated group must compute its Federal taxable income for purposes of article 32 of the Tax Law as if such corporation had computed its Federal taxable income on a separate basis for Federal income tax purposes. Provided, however, in the case of a member of a selling consolidated group, as defined in section 338(h)(10) of the Internal Revenue Code, with respect to which an election under such section 338(h)(10) has been made, Federal taxable income shall not include any gain or loss on the sale or exchange of stock of a target corporation which is not recognized by virtue of such election, but only if such member files on a combined return with such target corporation for the period including the acquisition date, as such term is defined in section 338(h)(2) of the Internal Revenue Code.

(d) Entire net income of a savings and insurance bank which conducts a life insurance business through a life insurance department under the authority of article 6-A of the Banking Law means the Federal taxable income which such bank is required to report to the United States Department of the Treasury under section 594(a)(1) of the Internal Revenue Code of 1954, as amended, adjusted as required by sections 18-2.3, 18-2.4 and 18-2.5 of this Subpart.

(e) The income actually reported or the income actually determined for Federal income tax purposes in not necessarily the same as the taxable income which should have been reported for Federal income tax purposes under the provisions of the Internal Revenue Code. Generally the determination of the Commissioner of Internal Revenue as to Federal taxable income is followed, but it is not binding on the Tax Commission.