15 U.S. Code § 657s - Limitations on subcontracting
Contract amounts expended by a covered small business concern on a subcontractor that is a similarly situated entity shall not be considered subcontracted for purposes of determining whether the covered small business concern has violated a requirement established under subsection (a) or (d).
The Administrator may change, by rule (after providing notice and an opportunity for public comment), a percentage specified in paragraphs (1) through (4) of subsection (a) if the Administrator determines that such change is necessary to reflect conventional industry practices among business concerns that are below the numerical size standard for businesses in that industry category.
With respect to a category of contracts to which a requirement under subsection (a) does not apply, the Administrator is authorized to establish, by rule (after providing notice and an opportunity for public comment), a requirement that a covered small business concern may not expend on subcontractors more than a specified percentage of the amount paid to the concern under a contract in that category.
A requirement established under paragraph (1) shall apply to all covered small business concerns.
The Administrator shall establish, through public rulemaking, requirements similar to those specified in paragraph (1) to be applicable to contracts for general and specialty construction and to contracts for any other industry category not otherwise subject to the requirements of such paragraph. The percentage applicable to any such requirement shall be determined in accordance with paragraph (1).