SBA size standard
$25 million
Measured by average annual receipts over the last 5 fiscal years
SBA table effective March 2023
Official definition
This U.S. industry comprises establishments primarily engaged in providing investigation, detective, and personal background check services.
FY2025 federal spending
The Department of Defense bought 67% of the $852.4M obligated under 561611 in FY2025.
- Contract awards
- 1,132
- Contract vehicles (IDVs)
- 540
Top buying agencies
- Department of Defense$574.3M
- Department of Justice$82.1M
- Department of Homeland Security$80.8M
- Department of Health and Human Services$28.5M
- Department of State$21.3M
FY2025 federal contract obligations, USAspending.gov
NAICS 561611 obligated $852 million in FY2025 across 1,132 contract awards. DoD is $574 million, or 67 percent, and that spend is the federal background investigation mission now consolidated under the Defense Counterintelligence and Security Agency. DOJ follows at $82 million, DHS at $81 million, HHS at $28 million, and State at $21 million.
What belongs here
Investigation, detective, and personal background check services.
- Guard and patrol work is 561612.
- Alarm and access control systems are 561621.
- Broader professional and technical support that includes some vetting is 541690.
Competing in this code
The code had 540 IDVs alongside 1,132 awards in FY2025, and in practice it is vehicle-gated: background investigation fieldwork is bought through a small number of large multiple-award contracts, and firms outside them do not compete. The investigator workforce is the asset: cleared, trained field investigators with the specific case type experience, in the geographies where the case volume sits. Because the government's clearance backlog is a persistent operational problem, capacity commitments carry unusual evaluation weight. A firm that can document surge hiring in a named metro area has something the incumbents are struggling to supply.
NAICS 561611 FAQ
What is the SBA size standard for NAICS 561611?
SBA sets it at $25 million in average annual receipts, averaged over your last five completed fiscal years. Come in at or under that and you are small on every NAICS 561611 solicitation, including the set-asides.
Which agencies buy investigative and background check services under NAICS 561611?
FY2025 obligations: DoD ($574 million), DOJ ($82 million), DHS ($81 million), HHS ($28 million), State ($21 million). DoD's two-thirds share is the consolidated federal background investigation mission, and the civilian remainder is agency-specific vetting and investigative support.
Can a firm compete in NAICS 561611 without a vehicle position?
Rarely. Most work is ordered against a small number of large multiple-award contracts, and the code had 540 IDVs alongside 1,132 awards in FY2025. The realistic sequence is subcontracting to a vehicle holder to build cleared investigator capacity, then competing at the next on-ramp.
What capability matters most in federal background investigation work?
Cleared field investigator capacity in the right geographies. Case volume is concentrated in specific metro areas, the government has a standing throughput problem, and evaluators weight documented surge hiring capability heavily. Corporate size matters much less than the investigator roster you can actually field.