What is segmentation in B2B marketing?
B2B market segmentation splits the companies you could sell to into groups that need different messages, channels or prices. A segment is only useful if you can count it, find the companies in it, and would write to them differently. There are four common bases, and each needs a different data source.
| Basis | What you split on | Example split | Where the data comes from |
|---|---|---|---|
| Firmographic | Industry, employee count, location, legal form, revenue | Accounting firms with 10 to 99 employees in Texas | Census SUSB and CBP tables (free), company websites, LinkedIn |
| Technographic | Tools a company already uses or has adopted | Firms already using AI tools vs firms that don't | Job posts, public integrations pages, Census survey rates for sizing |
| Needs-based | The problem the company is trying to solve | Firms short of staff in tax season vs firms trying to add advisory work | Customer interviews, sales call notes, support tickets |
| Behavioural | What the company has done with you or in public | Visited pricing twice, started a trial, asked a question in a forum | Your CRM, product analytics, public posts |
Firmographics tell you how big a segment is. Needs and behaviour tell you which part of it will buy now. A workable segment usually combines one firmographic filter with one need or behaviour. For splitting leads you already have in a CRM, see how to segment leads so your outreach changes; this post is about sizing the market before you have those leads.
How do you size a B2B segment with free Census data?
Use the Census Bureau's Statistics of U.S. Businesses (SUSB), which counts firms by industry and by company size. The SUSB program page describes it as annual data for US establishments with paid employees, by establishment industry and enterprise size. Its sister series, County Business Patterns, counts establishments (locations) with paid employees by industry and employment size, below national level. For selling to companies, firms are usually the better count, because one firm with five offices is one buyer.
Find the NAICS code
Look up your buyers' industry code. Offices of certified public accountants are 541211; other accounting services are 541219. The 2022 tables use 2017 NAICS codes, as the table page says.
Open the 2022 SUSB annual tables
On the 2022 SUSB annual tables page, the US and states by 6-digit NAICS file is a spreadsheet of about 38 MB. Its header gives a release date of 10 April 2025, and it is the latest annual SUSB year on census.gov as of 5 Nov 2026.
Filter by state, NAICS and size class
Each row gives firms, establishments, employment, payroll and receipts for one size class, such as 10 to 19 employees. Note the noise flag column next to employment and payroll.
Add size classes, not industries
The size classes inside one industry add up exactly. Industries don't: the SUSB glossary says a multi-establishment firm's establishments in the same industry and area are counted as one firm, so a firm with establishments in two industries is counted in each, so a company in two accounting codes can appear in both.
You can check the second rule in the file itself. The four 6-digit codes under 5412 (accounting, tax preparation, bookkeeping and payroll) show 50,885 + 19,464 + 4,484 + 45,390 = 120,223 firms, while the 5412 total row shows 120,085. The 138-firm gap is companies counted in more than one code. Two limits: these tables cover only firms with paid employees, so sole traders with no staff are missing, and 2022 counts will have moved by now.
A worked example: sizing segments for a sample accounting product
Sample company: Northwind Ledger, an invented practice-management tool priced at $3,000 a year per firm. It wants accounting firms large enough to have a process problem, so it drops firms under 10 employees. Counts below are US firms from the 2022 SUSB 6-digit NAICS spreadsheet, by enterprise size.
| Segment | NAICS | Size class | US firms (2022) | Revenue if every firm bought ($3,000 each) |
|---|---|---|---|---|
| A. CPA offices, small | 541211 | 10 to 19 employees | 4,257 | $12,771,000 |
| B. CPA offices, mid-sized | 541211 | 20 to 99 employees | 2,015 | $6,045,000 |
| C. Other accounting services, small | 541219 | 10 to 19 employees | 2,081 | $6,243,000 |
| D. Other accounting services, mid-sized | 541219 | 20 to 99 employees | 1,247 | $3,741,000 |
| Total | 9,600 | $28,800,000 |
Check the sums: 4,257 + 2,015 + 2,081 + 1,247 = 9,600 firms, and 9,600 × $3,000 = $28,800,000. Each row is firms × $3,000, for example 4,257 × 3,000 = 12,771,000. Because C and D are a different NAICS code from A and B, a few firms may sit in both, so treat 9,600 as an upper bound.
The $28.8 million is a ceiling, not a forecast. To get a serviceable figure, apply the share you could realistically reach. If Northwind can only sell in English to US firms and starts with two states, the same file gives CPA offices with 10 to 99 employees of 495 + 239 = 734 in California and 324 + 147 = 471 in Texas: 1,205 firms, worth 1,205 × $3,000 = $3,615,000 a year at full adoption. Our TAM, SAM and SOM glossary entry explains the three levels.
How do you pick your first B2B segment?
Pick the segment where you can reach buyers fastest and have the strongest evidence of the problem, as long as it is big enough to matter. Size comes from the Census count; the other scores come from your own interviews and lists. Here is a sample scoring sheet for the Northwind example, with scores from 1 (weak) to 3 (strong) that are invented for illustration.
| Segment | Size (firms) | Can we list named buyers? | Evidence of the problem | Can one person close it? | Total |
|---|---|---|---|---|---|
| A. CPA offices, 10 to 19 | 3 (4,257) | 3 | 3 | 3 | 12 |
| B. CPA offices, 20 to 99 | 2 (2,015) | 3 | 2 | 2 | 9 |
| C. Other accounting, 10 to 19 | 2 (2,081) | 2 | 1 | 3 | 8 |
| D. Other accounting, 20 to 99 | 1 (1,247) | 2 | 1 | 2 | 6 |
Technographic data can change the order. The Census Bureau's May 2026 report on AI use, from its biweekly Business Trends and Outlook Survey, found 37% of firms with 250 or more employees and 32% of those with 100 to 249 reported using AI as of the period ending 3 May 2026, and fewer than 20% of firms with four or fewer employees. If your product assumes buyers already use AI tools, that favours larger segments. The survey changed its question wording in November 2025, so don't compare rates across that change.
A practical rule: if the top segment has fewer than about 1,000 firms you can reach, check that the price can carry a long sales cycle. That threshold is our rule of thumb, not a Census figure.
How do segments turn into an ICP and campaigns?
Write one ICP line per segment, add the trigger that makes a firm likely to buy now, then build one campaign per segment. The fields below go in a sheet, one row per segment. The filled row is for the sample Northwind segment A.
Each segment gets its own list, its own first line and its own success measure. If two segments would get the same message, merge them. Our sibling post has a fuller ICP template built from won and lost deals. If you have no customers yet, a two-week test to define your ICP shows how to check a segment with outreach before building for it.
When the segment and trigger are written down, Siela's Lead Finder can take your website, suggest roles, industries, company sizes and locations to reach, and look for people with a reason to talk now, such as hiring for the work you automate. You check the form before it starts.
This week: open the SUSB 2022 spreadsheet, find your buyers' NAICS code, and write down the firm count for your target size class in your first two states.
Frequently asked questions
What are the main types of B2B market segmentation?
Four bases cover most B2B work: firmographic (industry, size, location), technographic (tools a company uses), needs-based (the problem it is trying to solve) and behavioural (what it has done with you or in public). Firmographics size a market; needs and behaviour pick who will buy soon.
What are the 5 methods of market segmentation?
Consumer marketing usually lists demographic, geographic, psychographic, behavioural and needs-based segmentation. In B2B, demographic becomes firmographic (industry and company size), geographic stays as location, psychographic is closer to a company's priorities or buying culture, and technographic is often added as a further basis.
What is the difference between County Business Patterns and SUSB?
County Business Patterns counts establishments, meaning individual locations, by industry and employment size, below national level. SUSB counts firms, grouping locations under common ownership, by enterprise size. For B2B sizing, SUSB firm counts are closer to the number of buyers, while CBP helps when you sell to individual sites.
How many segments should a small B2B team target?
Start with one, two at most. Every segment needs its own list, message and measure, and a team of one to three people can rarely keep more than two campaigns running well. Add the next segment only when the first produces replies and booked calls you can repeat.
Is segmentation the same as an ideal customer profile?
No. Segmentation divides the whole market into groups and sizes each one. An ideal customer profile describes the best-fit company inside the segment you chose, with the roles, needs and triggers you will target. You segment first, then write an ICP for the segment you pick.
Sources
- U.S. Census Bureau: 2022 SUSB annual data tables by establishment industry (checked 5 Nov 2026)
- U.S. Census Bureau: SUSB 2022, U.S. and states by 6-digit NAICS (spreadsheet, released 10 Apr 2025) (checked 5 Nov 2026)
- U.S. Census Bureau: SUSB glossary (checked 5 Nov 2026)
- U.S. Census Bureau: Statistics of U.S. Businesses program page (checked 5 Nov 2026)
- U.S. Census Bureau: County Business Patterns program page (checked 5 Nov 2026)
- U.S. Census Bureau: Large Firms With at Least 20 Employees Biggest AI Users (26 May 2026, checked 5 Nov 2026)