(a) General rule. In general, the gross income and deductions of an individual attributable to a trade or business (including a trade or business conducted by an employee referred to in paragraphs (b), (c), (d), or (e) of § 1.1402(c)-3), for the purpose of ascertaining his net earnings from self-employment, are to be determined by reference to the provisions of law and regulations applicable with respect to the taxes imposed by sections 1 and 3. Thus, if an individual uses the accrual method of accounting in computing taxable income from a trade or business for the purpose of the tax imposed by section 1 or 3, he must use the same method in determining net earnings from self-employment. Likewise, if a taxpayer engaged in a trade or business of selling property on the installment plan elects, under the provisions of section 453, to use the installment method in computing income for purposes of the tax under section 1 or 3, he must use the same method in determining net earnings from self-employment. Income which is excludable from gross income under any provision of subtitle A of the Internal Revenue Code is not taken into account in determining net earnings from self-employment except as otherwise provided in § 1.1402(a)-9, relating to certain residents of Puerto Rico, in § 1.1402(a)-11, relating to ministers or members of religious orders, and in § 1.1402(a)-12, relating to the term “possession of the United States” as used for purposes of the tax on self-employment income. Thus, in the case of a citizen of the United States conducting, in a foreign country, a trade or business in which both personal services and capital are material income-producing factors, any part of the income therefrom which is excluded from gross income as earned income under the provisions of section 911 and the regulations thereunder is not taken into account in determining net earnings from self-employment.

(b) Trade or business carried on. The trade or business must be carried on by the individual, either personally or through agents or employees. Accordingly, income derived from a trade or business carried on by an estate or trust is not included in determining the net earnings from self-employment of the individual beneficiaries of such estate or trust.

(c) Aggregate net earnings. Where an individual is engaged in more than one trade or business within the meaning of section 1402(c) and § 1.1402(c)-1, his net earnings from self-employment consist of the aggregate of the net income and losses (computed subject to the special rules provided in §§ 1.1402(a)-1 to 1.1402(a)-17 inclusive) of all such trades or businesses carried on by him. Thus, a loss sustained in one trade or business carried on by an individual will operate to offset the income derived by him from another trade or business.

(d) Partnerships. The net earnings from self-employment of an individual include, in addition to the earnings from a trade or business carried on by him, his distributive share of the income or loss, described in section 702(a)(9), from any trade or business carried on by each partnership of which he is a member. An individual's distributive share of such income or loss of a partnership shall be determined as provided in section 704, subject to the special rules set forth in section 1402(a) and in §§ 1.1402(a)-1 to 1.1402(a)-17, inclusive, and to the exclusions provided in section 1402(c) and §§ 1.1402(c)-2 to 1.1402(c)-7, inclusive. For provisions relating to the computation of the taxable income of a partnership, see section 703.

(e) Different taxable years. If the taxable year of a partner differs from that of the partnership, the partner shall include, in computing net earnings from self-employment, his distributive share of the income or loss, described in section 702(a)(9), of the partnership for its taxable year ending with or within the taxable year of the partner. For the special rule in case of the termination of a partner's taxable year as result of death, see §§ 1.1402(f) and 1.1402(f)-1.

(f) Meaning of partnerships. For the purpose of determining net earnings from self-employment, a partnership is one which is recognized as such for income tax purposes. For income tax purposes, the term “partnership” includes not only a partnership as known at common law, but, also a syndicate, group, pool, joint venture, or other unincorporated organization which carries on any trade or business, financial operation, or venture, and which is not, within the meaning of the Code, a trust, estate, or a corporation. An organization described in the preceding sentence shall be treated as a partnership for purposes of the tax on self-employment income even though such organization has elected, pursuant to section 1361 and the regulations thereunder, to be taxed as a domestic corporation.

(g) Nature of partnership interest. The net earnings from self-employment of a partner include his distributive share of the income or loss, described in section 702(a)(9), of the partnership of which he is a member, irrespective of the nature of his membership. Thus, in determining his net earnings from self-employment, a limited or inactive partner includes his distributive share of such partnership income or loss. In the case of a partner who is a member of a partnership with respect to which an election has been made pursuant to section 1361 and the regulations thereunder to be taxed as a domestic corporation, net earnings from self-employment include his distributive share of the income or loss, described in section 702(a)(9), from the trade or business carried on by the partnership computed without regard to the fact that the partnership has elected to be taxed as a domestic corporation.

(h) Proprietorship taxed as domestic corporation. A proprietor of an unincorporated business enterprise with respect to which an election has been made pursuant to section 1361 and the regulations thereunder to be taxed as a domestic corporation shall compute his net earnings from self-employment without regard to the fact that such election has been made.