Business Code 238900: Coverage, Reporting, and SBA Size Standard

Business code 238900 is the four-digit NAICS industry group called “Other Specialty Trade Contractors,” which covers construction businesses whose specialty work doesn’t fit the common trade categories like electrical, plumbing, or masonry. When you actually need to enter a code on a tax return or federal registration, though, the number you use is the six-digit version: 238990, “All Other Specialty Trade Contractors.”¹ The 238900 form appears on Bureau of Labor Statistics pages and other aggregated federal data because those agencies pad the four-digit industry group with zeros to display it in a six-digit format.² For practical purposes, if you came looking for 238900, you want 238990.

Why Two Numbers Point to the Same Industry

The North American Industry Classification System is the federal standard for sorting businesses by industry.³ It narrows from a two-digit sector down to a six-digit national industry. For this corner of construction:

23 — Construction
238 — Specialty Trade Contractors
2389 — Other Specialty Trade Contractors
238990 — All Other Specialty Trade Contractors

238900 is just 2389 displayed at six digits. 238990 is the real reportable code.

What Work Falls Under 238990

This code is a catch-all for specialty construction trades that don’t have their own dedicated NAICS classification. It covers new construction, additions, alterations, maintenance, and repairs by contractors whose primary work doesn’t fit under foundation work, building equipment, finishing trades, or site preparation.¹

The Census Bureau lists these as examples of businesses that belong here:

Fence installation (residential and commercial fencing contractors whose primary business is fencing, not landscaping)
Outdoor swimming pool construction
Residential and commercial driveway and parking lot paving or sealing
Interlocking brick, block, and paver installation for patios and walkways
Scaffold erecting and dismantling
Steeplejack work on steeples, smokestacks, and similar tall structures
Manufactured and mobile home set-up and tie-down
Billboard erection
Crane rental when supplied with an operator
Sandblasting building exteriors

If your primary revenue comes from one of these activities and no more specific NAICS code fits, 238990 is likely correct.

Work That Does Not Belong Under 238990

Misclassifying a business under 238990 when a more specific code exists is a common mistake. The Census Bureau publishes cross-references showing where frequently confused activities actually go.¹

Site preparation — excavation, grading, demolition, dirt moving, septic installation, and land clearing — belongs under 238910.⁴
Paving public streets and highways belongs under 237310 (Highway, Street, and Bridge Construction). The driveway and parking lot paving that fits here is private.
Renting construction equipment without supplying an operator is 532412, a leasing business rather than a trade.
Cleaning and maintaining an existing swimming pool is 561790, a building service.
Asbestos removal, lead paint abatement, and similar hazardous material work is 562910.
Installing invisible pet containment systems is classified as electrical work under 238210.
Indoor swimming pool construction is 236220, commercial building construction.

One line that trips outdoor contractors up: a company that primarily installs fences, patios, or retaining walls as standalone projects belongs in construction, but a company that provides landscape design and maintenance and installs those structures as part of a broader landscaping package typically belongs under 561730 (Landscaping Services). Your primary revenue source decides it.

Where You Report the Code

Sole proprietors enter the principal business activity code on Schedule C (Form 1040), line B.⁵ C-corporations enter it on Form 1120, Schedule K, and S-corporations do the same on Form 1120-S.⁶ The IRS uses the code for statistical benchmarking against businesses in the same industry, not to compute tax.

Any business pursuing federal contracts must also register in SAM.gov and identify its NAICS codes there.⁷ You can list several codes if you do work across multiple categories, but your primary code should reflect where most of your revenue comes from. Contracting officers assign a NAICS code to each solicitation, and your registered codes determine which set-asides you can bid on.

The SBA Size Standard for 238990

For NAICS 238990, the SBA defines a small business as one with average annual receipts of $19.0 million or less.⁸ That figure isn’t last year’s revenue. The SBA calculates it as total receipts over your most recently completed five fiscal years, divided by five.⁹

If you’ve been in business fewer than five complete fiscal years, the SBA takes your total receipts for the time you’ve operated, divides by the number of weeks, and multiplies by 52 to annualize.⁹ “Receipts” means all revenue from any source, including service fees, interest, and commissions, reduced by returns and allowances. It roughly corresponds to total income plus cost of goods sold on your tax return.

Crossing the $19.0 million five-year average means you lose small business status for solicitations coded to 238990.

What Happens If You Pick the Wrong Code

Choosing the wrong NAICS code is not itself an IRS violation. Because the agency uses the code for statistical analysis rather than tax calculation, a wrong code alone won’t change what you owe. It can draw attention, though. If your income and expense ratios look unusual against the industry the code places you in, it can flag your return for review.

The more serious consequences involve federal contracting. Different codes carry different size standards, so using a code with a higher revenue threshold than 238990’s $19.0 million could make a non-small business appear to qualify for small business set-asides. Willful misrepresentation of size status to win a set-aside triggers a presumption of loss to the government equal to the total contract amount. Additional penalties include suspension or debarment from federal contracting, civil liability under the False Claims Act, and criminal prosecution under the Small Business Act with potential fines and imprisonment.¹⁰

Those penalties apply to willful misrepresentation, not honest mistakes. A business that acted in good faith reliance on an SBA size advisory opinion is protected. The line between careless and willful can be uncomfortably thin when the government is doing the interpreting, so getting the code right from the start pays off.

How to Choose and Update Your Code

The rule is straightforward: your primary NAICS code should reflect the activity that produces the largest share of your annual revenue. A fencing contractor who also does some driveway sealing uses the code tied to fence work if fencing brings in most of the income. You can list multiple codes in SAM.gov, but a tax return asks for a single primary code.

Search the Census Bureau’s NAICS lookup for the most specific six-digit code that matches your primary activity.³ Fall back to the residual 238990 only after confirming no more specific code captures what you do. If your primary work is electrical, plumbing, concrete, roofing, or any of the dozens of trades with dedicated codes, those take priority even if you occasionally do 238990-type work.

When your primary revenue source shifts, update the code. On SAM.gov, edit your NAICS codes through the entity registration portal under Core Data. On your tax return, enter the new code the following year. There’s no formal IRS process to change a previously reported code because you report it fresh each filing year.

1
Census Bureau. North American Industry Classification System (NAICS) – 238990
2
U.S. Bureau of Labor Statistics. NAICS 238900 – Other Specialty Trade Contractors
3
U.S. Census Bureau. North American Industry Classification System (NAICS)
4
Census Bureau. North American Industry Classification System (NAICS) – Subsector 238
5
Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025)
6
Internal Revenue Service. Instructions for Form 1120 (2025)
7
U.S. Small Business Administration. Basic Requirements
8
eCFR. 13 CFR Part 121 – Small Business Size Regulations
9
eCFR. 13 CFR 121.104 – How Does SBA Calculate Annual Receipts
10
eCFR. 13 CFR 121.108 – What Are the Penalties for Misrepresentation of Size Status