Aggregation rules
(b) Aggregation rules(1) General rule. Trades or businesses may be aggregated only if an individual or RPE can demonstrate that (i) The same person or group of persons, directly or by attribution under sections 267(b) or 707(b), owns 50 percent or more of each trade or business to be aggregated, meaning in the case of such trades or businesses owned by an S corporation, 50 percent or more of the issued and outstanding shares of the corporation, or, in the case of such trades or businesses owned by a partnership, 50 percent or more of the capital or profits in the partnership; (ii) The ownership described in paragraph (b)(1)(i) of this section exists for a majority of the taxable year, including the last day of the taxable year, in which the items attributable to each trade or business to be aggregated are included in income; (iii) All of the items attributable to each trade or business to be aggregated are reported on returns with the same taxable year, not taking into account short taxable years; (iv) None of the trades or businesses to be aggregated is a specified service trade or business (SSTB) as defined in 1.199A-5; and (v) The trades or businesses to be aggregated satisfy at least two of the following factors (based on all of the facts and circumstances): (A) The trades or businesses provide products, property, or services that are the same or customarily offered together. (B) The trades or businesses share facilities or share significant centralized business elements, such as personnel, accounting, legal, manufacturing, purchasing, human resources, or information technology resources. (C) The trades or businesses are operated in coordination with, or reliance upon, one or more of the businesses in the aggregated group (for example, supply chain interdependencies). (2) Operating rules(i) Individuals. An individual may aggregate trades or businesses operated directly or through an RPE to the extent an aggregation is not inconsistent with the aggregation of an RPE. If an individual aggregates multiple trades or businesses under paragraph (b)(1) of this section, QBI, W-2 wages, and UBIA of qualified property must be combined for the aggregated trades or businesses for purposes of applying the W-2 wage and UBIA of qualified property limitations described in 1.199A-1(d)(2)(iv). An individual may not subtract from the trades or businesses aggregated by an RPE but may aggregate additional trades or businesses with the RPE's aggregation if the rules of this section are otherwise satisfied. (ii) RPEs. An RPE may aggregate trades or businesses operated directly or through a lower-tier RPE to the extent an aggregation is not inconsistent with the aggregation of a lower-tier RPE. If an RPE itself does not aggregate, multiple owners of an RPE need not aggregate in the same manner. If an RPE aggregates multiple trades or businesses under paragraph (b)(1) of this section, the RPE must compute and report QBI, W-2 wages, and UBIA of qualified property for the aggregated trade or business under the rules described in 1.199A-6(b). An RPE may not subtract from the trades or businesses aggregated by a lower-tier RPE but may aggregate additional trades or businesses with a lower-tier RPE's aggregation if the rules of this section are otherwise satisfied.