(a) In all cases where a combined report is required or permitted (see Subpart 6-2 of this Part) a combined franchise tax report must be submitted by the taxpayer designated as the parent responsible for paying the combined tax on form CT-3-A. In addition, each related corporation in the combined group must submit such other reports and other information which the commissioner may require.

(b) It is not necessary that all corporations in the combined group have the same accounting period. (See Subpart 2-1 of this Title for information relating to accounting periods.) Where a corporation’s taxable year is different from that of the taxpayer designated as the parent, the applicable taxable year of such corporation to be included in the combined group is the taxable year that ends within the taxable year of the taxpayer designated as the parent. The commissioner may permit or require a taxpayer to use a different accounting period where appropriate.

(c) If any corporation in the combined group is a stockholder of a tax exempt DISC, a consolidated franchise tax report, form CT-3C, which includes that corporation and the DISC, must be submitted with the combined report. A copy of the information report, form CT-3B, filed by the tax exempt DISC must also be submitted with the combined report.