NAICS Code 561621 — Security Systems Services (except Locksmiths)

National Industry in the official 2022 North American Industry Classification System (U.S. Census Bureau). It is one of 2 national industries under 56162 (Security Systems Services).

Code	561621
Title	Security Systems Services (except Locksmiths)
Level	National Industry (6-digit)
Edition	NAICS 2022 edition
SBA size standard	$25 million in average annual receipts

Official definition (2022 NAICS)

This U.S. industry comprises establishments primarily engaged in (1) selling security alarm systems, such as burglar and fire alarms, along with installation, repair, or monitoring services or (2) remote monitoring of electronic security alarm systems.

Is a business under 561621 "small"?

Under the SBA size standards (13 CFR 121.201, effective March 17, 2023), a business classified in NAICS 561621 qualifies as a small business if it does not exceed $25 million in average annual receipts. Small-business status determines eligibility for federal set-aside contracts, SAM.gov certifications and SBA loan programs — receipts are averaged over the latest 5 fiscal years.

Where 561621 sits in the hierarchy

Level	Code	Title
Sector	56	Administrative and Support and Waste Management and Remediation Services
Subsector	561	Administrative and Support Services
Industry Group	5616	Investigation and Security Services
NAICS Industry	56162	Security Systems Services
National Industry	561621	Security Systems Services (except Locksmiths)

Related SIC codes

Via the official U.S. Census concordance (1987 SIC ↔ NAICS), shown only where the industry definition is unchanged in NAICS 2022.

SIC code	Title
7382	Security Systems Services

Related National Industry codes

• 561622 — Locksmiths

Data: official 2022 NAICS structure, descriptions and Census concordances, U.S. Census Bureau — U.S. government works in the public domain (17 U.S.C. §105). Suggested reference, not an official determination.