13 C.F.R. § 121.402
What size standards are applicable to Federal Government Contracting programs?
(a) A concern must not exceed the size standard for the NAICS code specified in the solicitation. The contracting officer must specify the size standard in effect on the date the solicitation is issued. If SBA amends the size standard and it becomes effective before the date initial offers (including price) are due, the contracting officer may amend the solicitation and use the new size standard.
(b) The procuring agency contracting officer, or authorized representative, designates the proper NAICS code and corresponding size standard in a solicitation, selecting the single NAICS code which best describes the principal purpose of the product or service being acquired. Except for multiple award contracts as set forth in paragraph (c) of this section, every solicitation, including a request for quotations, must contain only one NAICS code and only one corresponding size standard.
(1) Primary consideration is given to the industry descriptions in the U.S. NAICS Manual, the product or service description in the solicitation and any attachments to it, the relative value and importance of the components of the procurement making up the end item being procured, and the function of the goods or services being purchased.
(2) A procurement is generally classified according to the component which accounts for the greatest percentage of contract value. Acquisitions for supplies must be classified under the appropriate manufacturing or supply NAICS code, not under a Wholesale Trade or Retail Trade NAICS code. A concern that submits an offer or quote for a contract, order, or subcontract where the NAICS code assigned to the contract, order, or subcontract is one for supplies, and furnishes a product it did not itself manufacture or produce, is categorized as a nonmanufacturer and deemed small if it has 500 or fewer employees and meets the requirements of § 121.406(b).
(c) Multiple Award Contracts (see definition at § 125.1).
(1) For a Multiple Award Contract, the contracting officer must:
(i) Assign the solicitation a single NAICS code and corresponding size standard which best describes the principal purpose of the acquisition as set forth in paragraph (b) of this section, only if the NAICS code will also best describe the principal purpose of each order to be placed under the Multiple Award Contract; or
(ii) Divide the solicitation into discrete categories (such as Contract Line Item Numbers (CLINs), Special Item Numbers (SINs), Sectors, Functional Areas (FAs), or the equivalent), and assign each discrete category the single NAICS code and corresponding size standard that best describes the principal purpose of the goods or services to be acquired under that category (CLIN, SIN, Sector, FA or equivalent) as set forth in paragraph (b) of this section. A concern must meet the applicable size standard for each category (CLIN, SIN, Sector, FA or equivalent) for which it seeks an award as a small business concern.
(2)(i) The contracting officer must assign a single NAICS code for each order issued against a Multiple Award Contract. The NAICS code assigned to an order must be a NAICS code included in the underlying Multiple Award Contract. When placing an order under a Multiple Award Contract with multiple NAICS codes, the contracting officer must assign the NAICS code and corresponding size standard that best describes the principal purpose of each order. In cases where an agency can issue an order against multiple SINs with different NAICS codes, the contracting officer must select the single NAICS code that best represents the acquisition. If the NAICS code corresponding to the principal purpose of the order is not contained in the underlying Multiple Award Contract, the contracting officer may not use the Multiple Award Contract to issue that order.
(ii) With respect to an order issued against a multiple award contract, an agency will receive small business credit for goaling only if the business concern awarded the order has represented its status as small for the underlying multiple award contract for the same NAICS code as that assigned to the order, provided recertification has not been required or occurred for the contract or order.
(d) The NAICS code assigned to a procurement and its corresponding size standard is final unless timely appealed to SBA's Office of Hearings and Appeals (OHA), or unless SBA assigns an NAICS code or size standard as provided in paragraph (e) of this section.
(e) When a NAICS code designation or size standard in a solicitation is unclear, incomplete, missing, or prohibited, SBA may clarify, complete, or supply a NAICS code designation or size standard, as appropriate, in connection with a formal size determination or size appeal.
(f) Any offeror or other interested party adversely affected by an NAICS code designation or size standard designation may appeal the designations to OHA under part 134 of this chapter.