Returns — Persons required to file.

Each of the following persons shall file a return with the Mayor stating specifically the items of his gross income and the items claimed as deductions and credits allowed under this chapter, and such other information for the purpose of carrying out the provisions of this chapter as the Mayor may require:

(1) Residents and nonresidents. — Every nonresident of the District receiving income subject to tax pursuant to this chapter and every resident of the District, except a fiduciary, who is required to file a federal return under the provisions of § 6012 of the Internal Revenue Code of 1986 [26 U.S.C. § 6012].

(2) Fiduciaries. —

(A) Every individual, if single, or if married and not living with spouse, for whom he or she acts, having met the filing requirements of § 6012 of the Internal Revenue Code of 1986 [26 U.S.C. § 6012];

(B) Every individual, if married and living with spouse, for whom he or she acts, having met the filing requirements of § 6012 of the Internal Revenue Code of 1986 [26 U.S.C. § 6012], except that if the fiduciary elects to file a separate return, the provisions of § 6012 of the Internal Revenue Code of 1986 [26 U.S.C. § 6012], relating to filing requirements for separate returns, shall be followed;

(C) Every estate for which he or she acts, the gross income of which for the taxable year is in excess of its personal exemption of $885 for taxable years beginning after December 31, 1986, $1,025 for taxable years beginning after December 31, 1987, $1,160 for taxable years beginning after December 31, 1988, $1,270 for taxable years beginning after December 31, 1989, and $1,370 for taxable years beginning after December 31, 1990; and

(D) Every trust for which he or she acts, the gross income of which for the taxable year is $100 or over.

(3) Joint fiduciaries. — A return by one of 2 or more joint fiduciaries filed with the Mayor shall be sufficient compliance with the provisions of subsection (b) of this section.

(4) If any resident or nonresident or any fiduciary is unable to make his own return, the return shall be made by his duly authorized agent.

(5) Corporations and financial institutions. —

(A) Every corporation or financial institution engaging in or carrying on any trade or business within the District or receiving income from sources within the District within the meaning of §§ 47-1810.01 to 47-1810.03 , even if the business or source income is exempt under other provisions of this chapter.

(B) Affiliated corporations (including affiliated incorporated financial institutions) shall file separate returns unless an election is made in accordance with the requirements of subparagraph (C) of this paragraph.

(C)

(i) On or before the due date, including any extensions, for filing the original tax return, an affiliated group may elect to consolidate the taxable income of all members of the affiliated group. The election shall be binding on the affiliated group; provided, that the election shall terminate automatically upon the revocation or termination of its federal consolidation election.

(ii) In order to file a consolidated return, the affiliated group shall have properly elected, or was required, to file a consolidated federal return under section 1501 of the Internal Revenue Code of 1986 [26 U.S.C. § 1501].

(iii) The election to file a consolidated return shall be accompanied by written consents to the election signed by each of the members of the affiliated group.

(iv) The District may require that a consolidated return be filed for an affiliated group that is eligible, but has not elected, to file a consolidated return under this subparagraph if the District determines that a consolidated return is necessary to prevent evasion of taxes or to clearly reflect the taxable income that is attributable to the business conducted in the District by the affiliated group.

(v) In taxable years after the year of the election, a corporation that was not a member of the original affiliated group in the year of the election but is a member of the affiliated group in the current year shall be deemed to have waived any objection to the filing of the consolidated return in the District by its consent, if any, to join in filing a consolidated return in the District by the parent of the District affiliated group. In the case of a corporation that is a member of the affiliated group for a part of the taxable year, the consolidated return shall include the income of the corporation for the part of the year that it is a member of the affiliated group.

(vi) All members of the affiliated group that elected or was required to file a consolidated return in the District are jointly and severally liable for the taxes, interest, and penalties of the affiliated group.

(vii) The Mayor may promulgate regulations to determine, compute, assess, collect, and adjust, the tax liability of the affiliated group.

(D) For purposes of this paragraph, the term “affiliated group” means an affiliated group as defined in section 1504 of the Internal Revenue Code of 1986 [26 U.S.C. § 1504]; provided, that the affiliated group shall not include any corporation which does not have gross income derived from sources within the District.

(6) Unincorporated businesses. — Every unincorporated business engaging in or carrying on any trade or business within the District or receiving income from sources within the District within the meaning of §§ 47-1810.01 to 47-1810.03 and having a gross income of more than $12,000, regardless of whether it has a net income. The return shall be made by the taxpayer or taxpayers liable for the payment of the tax.

(7) Partnerships. — Every partnership, other than partnerships subject to the taxes imposed by §§ 47-1808.01 to 47-1808.06 on unincorporated businesses, engaged in any trade or business, or receiving income from sources within the District. There shall be included in such return the names and addresses of the individuals who would be entitled to share in the net income of the partnership, if distributed, and the amount of distributive share of each individual.

(7A) Exempt Organizations. — Every exempt organization exempt from tax that has unrelated business income subject to tax under section 511 of the Internal Revenue Code of 1986 [26 U.S.C. § 511] or income subject to tax under section 527 of the Internal Revenue Code of 1986 [26 U.S.C. § 527], as provided under § 47-1802.01 .

(8) Registration. — No person shall engage in or continue to engage in a trade, business or profession subject to taxes under the provisions of this chapter without first registering to do so. Such registration shall be made in such manner and on such forms as the Mayor shall prescribe and registration shall not be transferable. Whoever engages in a trade, business or profession which is subject to tax under the provisions of this chapter without first registering to do so, as required by this section, shall, upon conviction thereof be fined not more than $500. Such failure to register shall also be subject to a civil penalty of $50 a day for each day that such failure continues.