Business Buyer School Research · Short version · Version 2026.1
The 100 Industries With the Most Small Firms to Look At
Business Buyer School 2026 Acquisition Supply Study, short version · Version 2026.1 · Published October 6, 2026. These counts measure how many small firms exist, not how many are for sale. The top 100 is the 100 highest scores on the Acquisition Supply Index, which combines density, share and count of small firms; it is not a ranking by pool size.
Every number is on the open full study: Short version · Full study · Methodology · Data.
The short answer
Business Buyer School analysis of U.S. Census Bureau data found that 89% of U.S. employer firms have fewer than 20 employees. Across 152 industries where buying a small business is plausible, the highest scores on the Acquisition Supply Index (density, share and count of small firms combined) go to home builders (residential building construction), real estate agent and broker offices, personal care (salons, barbers, nails) and auto repair and maintenance. Manufacturing industries such as machinery, chemicals, glass and forging score lowest.
This counts small firms that exist, not businesses for sale. About 70% of the firms under 20 employees have fewer than 5 people, so the pool of firms with a real operation is smaller.
Three things worth knowing
- Look at firms with 5 or more employees. Restaurants (289,301 firms with 5 to 99 employees), HVAC, plumbing and electrical contractors (76,499) and dentists (74,220) have the largest staffed pools.
- Higher supply scores tend to go with lower durability scores. Industries with higher index scores tend to score lower on the Report 2 durability score (correlation -0.53). That is a pattern across industries, not a cause.
- Supply does not predict recession resistance (correlation 0.14).
Highest index scores (top 10 of the top 100)
| Industry | Firms under 20 employees (share) | Firms under 20 employees | Firms with 5 to 99 employees |
|---|---|---|---|
| Home builders (residential building construction) (2361) | 97.2% | 201,496 | 42,078 |
| Real estate agent and broker offices (5312) | 98.9% | 149,290 | 10,047 |
| Personal care (salons, barbers, nails) (8121) | 95.8% | 135,200 | 42,203 |
| Auto repair and maintenance (8111) | 95.9% | 143,105 | 50,407 |
| Law firms (5411) | 95.1% | 160,064 | 42,599 |
| Chiropractors, optometrists, physical therapists and similar practices (6213) | 95.0% | 157,071 | 46,197 |
| Management and technical consulting (5416) | 95.1% | 194,796 | 30,531 |
| Lessors of real estate (landlords, self-storage) (5311) | 95.6% | 96,756 | 18,543 |
| Finishing contractors (drywall, painting, flooring) (2383) | 94.0% | 117,820 | 34,544 |
| Specialized design (interior, graphic, industrial) (5414) | 97.6% | 36,038 | 6,149 |
Not in the top 100
The other 52 industries have lower index scores, mostly lower small-firm density; 40 of them still have more firms under 20 employees than the smallest count in the top 100, so the index is not a ranking by pool size. The lowest scores are Forging and stamping, Electrical equipment makers, Paint and coatings makers, Animal feed makers, Glass product makers. The full list is in the data file.
Common acquisition targets
| Industry | Supply rank of 152 | Firms under 20 employees | Firms with 5 to 99 employees |
|---|---|---|---|
| Home builders (residential building construction) (2361) | 1 | 201,496 | 42,078 |
| Auto repair and maintenance (8111) | 4 | 143,105 | 50,407 |
| Management and technical consulting (5416) | 7 | 194,796 | 30,531 |
| Finishing contractors (drywall, painting, flooring) (2383) | 9 | 117,820 | 34,544 |
| Insurance agencies (5242) | 11 | 124,571 | 30,985 |
| Dentists (6212) | 12 | 113,495 | 74,220 |
| Janitorial, landscaping and pest control (5617) | 13 | 200,133 | 64,969 |
| Accounting, tax and bookkeeping (5412) | 15 | 114,312 | 30,671 |
| Foundation, framing, roofing and exterior contractors (2381) | 22 | 93,665 | 35,763 |
| HVAC, plumbing and electrical contractors (2382) | 25 | 173,219 | 76,499 |
| Dry cleaning and laundry (8123) | 30 | 23,238 | 7,619 |
| Restaurants (7225) | 60 | 341,443 | 289,301 |
| Printing (3231) | 72 | 18,181 | 9,472 |
| Home health care (6216) | 119 | 18,401 | 15,087 |
Each row is a broad industry group, not one trade. HVAC cannot be separated from plumbing, or landscaping from janitorial or pest control, in these sources.
What this does and does not tell you
- It shows how many small employer firms exist in each industry, not how many are for sale.
- There is no price, profit or owner intent data here.
- A franchise location counts as a small firm.
- A firm with locations in several industries is counted in each.
Read the full study
Every table, the key statistics, what is and is not measured and the method. It is open to read, with no sign up.
How this was measured
Business Buyer School counted employer firms by size in each of 152 four digit industries from Census SUSB 2022 and combined small firm density, share and count into a 0 to 100 Acquisition Supply Index. The top 100 is the 100 highest index scores. It is not a ranking by pool size, and a separate table shows industries with the most staffed small firms. The methodology has the sources, formulas, exclusions and limits, and the data page has the table and downloads.
How to cite
Cite as: Business Buyer School, 100 Industries Ranked by Acquisition Supply, https://businessbuyerschool.com/research/acquisition-supply-index/. Version 2026.1. Published October 6, 2026.
A data license has not been published; short quotations with attribution and a link are welcome.
Take this into your own search
Industry research is context, not a verdict on any one business. These free parts of the school show how to use it.
- Write your Buy Box: set the type of business, size and hard exclusions before you search.
- Cleaning, landscaping and HVAC compared: how the same principles show up in three trades.
- See the curriculum or start free with Business Buyer School.