NAICS Code 541990 Explained: Who It's For
NAICS 541990 is All Other Professional, Scientific, and Technical Services, with a $19.5M SBA size standard. What it covers, who uses it, and when to choose it.
NAICS code 541990 is "All Other Professional, Scientific, and Technical Services." It's the catch-all code within sector 54 for professional, scientific, or technical services that aren't specifically classified under another code. Its SBA size standard is $19.5 million in average annual receipts, so a firm under that threshold counts as small for 541990 opportunities.
This guide explains what 541990 actually covers, who should use it, and how it compares to more specific codes.
What 541990 covers
541990 captures specialized professional or technical services that don't fit a dedicated NAICS code. Per the classification, these are establishments primarily engaged in providing professional, scientific, or technical services except those specifically classified elsewhere in subsector 541.
Common examples include:
- Subject-matter expert and advisory services that aren't management consulting (541611) or engineering (541330)
- Specialized technical services without a dedicated code
- Niche scientific or professional support work
Because it's a residual ("all other") category, 541990 is broad — but that's also its limitation (see below).
Size standard
| NAICS 541990 | |
|---|---|
| Title | All Other Professional, Scientific, and Technical Services |
| Sector | 54 — Professional, Scientific, and Technical Services |
| SBA size standard | $19.5M average annual receipts |
| Type | Revenue-based |
Confirm the current figure on our NAICS 541990 page — SBA size standards are periodically adjusted for inflation.
When to choose 541990 — and when not to
Choose 541990 when your service genuinely doesn't fit a more specific 541-series code. It's legitimately the right home for a lot of specialized advisory and technical work.
Avoid defaulting to it when a more specific code fits. Agencies often solicit under specific codes, and a precise NAICS:
- Matches you to more relevant opportunities
- Signals you're a specialist, not a generalist
- May carry a more favorable size standard
If management consulting is your core, 541611 is likely better; for engineering, 541330; for IT, the 541511/541512/541519 family. Use 541990 as a secondary code to capture edge work, with a more specific primary code where one exists.
How to add it
Add 541990 (and any secondary codes) to your SAM.gov registration. Not sure which codes fit? Start with how to find your NAICS code or browse the NAICS directory.
Frequently asked questions
What is NAICS 541990? All Other Professional, Scientific, and Technical Services — the residual code in sector 54 for professional/technical services not classified elsewhere.
What is the size standard for 541990? $19.5 million in average annual receipts (revenue-based).
Should 541990 be my primary NAICS code? Only if no more specific 541-series code fits your core service. A precise primary code usually matches better and signals specialization.
What's the difference between 541990 and 541611? 541611 is Administrative and General Management Consulting; 541990 is the catch-all for professional/technical services without a dedicated code. Use the specific one when it applies.
Key takeaways
- 541990 = All Other Professional, Scientific, and Technical Services, a residual catch-all in sector 54.
- Size standard: $19.5M average annual receipts.
- Prefer a more specific code as your primary when one fits; use 541990 for genuine edge cases.
- Add it in SAM.gov; see the 541990 page for current details.