District of Columbia Code Division VIII. General Laws. § 47-1805.02a. Combined reporting required.

(a) For tax years beginning after December 31, 2010, a taxpayer engaged in a unitary business with one or more other persons that are part of a water's-edge combined group reporting pursuant to § 47-1810.07 shall file a combined report, which includes the income, determined under § 47-1810.04 and § 47-1810.05 and the allocation and apportionment factors determined under § 47-1810.02 and the pertinent regulations of all such persons that are members of the unitary business, and other information as required by the Chief Financial Officer. If a worldwide combined reporting election has been made, the taxpayer shall file a combined report that includes such income and factors of all the persons that are members of the unitary business, and any other information as required by the Chief Financial Officer.

(b) The Chief Financial Officer may require, by regulation, a combined report to include the income and associated apportionment factors of any persons that are not included pursuant to subsection (a) of this section but that are members of a unitary business to reflect proper apportionment of income of the entire unitary business.

(c) If the Chief Financial Officer determines that the reported income or loss of a taxpayer engaged in a unitary business with any person not included represents an avoidance or evasion of tax by the taxpayer, the Chief Financial Officer may require, on a case-by-case basis, that all or any part of the income and associated apportionment factors be included in the taxpayer's combined report.

(d) With respect to inclusion of associated apportionment factors pursuant to this section, the Chief Financial Officer may require the exclusion of any one or more of the factors, the inclusion of one or more additional factors, that will fairly represent the taxpayer's business activity in the District, or the employment of any other method to effectuate a proper reflection of the total amount of income subject to apportionment and an equitable allocation and apportionment of the taxpayer's income.

(e) The Chief Financial Officer shall adopt regulations as necessary to implement combined reporting and to ensure that the tax liability or net income of any taxpayer whose income derived from or is attributable to sources within the District that is required to be determined by a combined report pursuant to § 47-1810.02 or § 47-1810.07 and of each entity included in the combined report, both during and after the period of inclusion in the combined report, is properly reported, determined, computed, assessed, collected, or adjusted.

(f) The Chief Financial Officer shall adopt regulations as necessary prescribing the form and manner of all returns and reports required under this section, including the time, place, and extension of such returns and reports.

(g) Any taxpayer election made under § 47-1805.02(5)(C) and the pertinent regulations to file a consolidated return is revoked for tax years beginning after December 31, 2010.