General rule. Where a person subject to tax under chapter 18 of title 47 of the D.C. Official Code is engaged in a unitary business with one or more other persons that are related by common ownership, the taxpayer member must determine its tax liability based upon the income and apportionment information of all persons included in the combined group using a combined report unless it is an excluded person under 9 DCMR § 157.3.
Excluded persons. Persons that are not included in a combined group and therefore not included in a combined report filed thereby, irrespective of whether they are engaged in a unitary business with a member of such group, include, unless such persons are otherwise required to be included under D.C. Official Code § 47-1805.02 a: any insurance company subject to premium tax under D.C. Official Code § 47-2608 (2005 Repl.) or § 31-3403.01 (2005 Repl.) exempt organization including an organization that has unrelated business income subject to tax under I.R.C. § 511; Qualified High Technology Company (QHTC); person, regardless of the place incorporated or formed, if the average of its property, payroll, and sales factors outside the U.S. is eighty percent or more; or as otherwise provided in chapter 18 of title 47 of the D.C. Official Code.
D.C. Mun. Regs. tit. 9, r. 9-157