Sales Outsourcing Agencies: Scattered Across Four Codes

There is no official list of sales outsourcing agencies, because outsourced sales has no classification of its own. The firms scatter across marketing consulting, advertising and telemarketing, and in each of those codes they are a minority among businesses doing something else entirely.

If you sell to agencies, this is the vertical where buying a list does the most damage, because the list will look plausible and be mostly wrong.

What NAICS code covers sales agencies?

None, and the mechanism is worth understanding: NAICS generally assigns an establishment to an industry based on its principal product or service. A multi-service agency doing demand generation, content and SDR work is filed under whichever activity is largest, so two nearly identical agencies can sit in different codes.

The three codes that bracket the market, all 2025 annual averages:

• NAICS 541613, Marketing Consulting Services: 97,330 private-sector establishments and 318,330 average annual employment
• NAICS 541810, Advertising Agencies: 39,453 establishments and 207,790 employment
• NAICS 561422, Telemarketing Bureaus and Other Contact Centers: 11,814 establishments

Roughly 148,000 establishments across the three, of which outsourced B2B sales agencies are a small and unmeasured fraction. For scale, QCEW derived 12.1 million establishments and 155.0 million employed people across all covered industries in 2024.

The telemarketing code is the interesting one. It is the closest thing to an outbound-calling classification, it is the smallest of the three, and it carries connotations most modern SDR agencies would reject, which is precisely why so few of them file under it.

How to build the list when no code fits

1. Define the service, not the sector. Does the agency supply people who prospect on a client's behalf, run campaigns, or advise on strategy? Those are three businesses.
2. Size with QCEW, which publishes quarterly employment and wage data at national, state, county and metropolitan levels by industry, and treat the result as an upper bound.
3. Qualify on operating signals: whether the agency hires SDRs, whether it runs sending infrastructure, which sales stack it operates. These separate a sales agency from a marketing agency more reliably than any code.
4. Watch for the annual-average subtlety when you compare years: a QCEW annual-average establishment count is the average of the four quarterly counts, and the annual file stores average establishments and average employment as separate fields.
5. Expect high churn. Agencies form, merge and dissolve faster than classification updates, so a list decays quickly and needs a refresh cadence.

Defining the category and assembling firms against it is the specific problem Causo's GTM agency prospecting is built for.

Why generic databases miss sales agencies

There is no reliable category to filter on, so any "agency" filter returns advertising, PR, market research, design and management consulting together.

Self-description is the only signal, and agency websites describe aspiration as much as practice.

Service mix is invisible. Whether a firm supplies SDRs, runs paid media, or writes strategy decks does not appear as a field, and it is the only thing that matters for fit.

And size data misleads: an agency with fifteen staff running outbound for twelve clients and a fifteen-person design studio are indistinguishable in a business database. The general failure of buying rows rather than qualifying them is covered in B2B prospecting for founders.

Selling to sales agencies: who decides

The founder or managing director, in almost every case. These are small, owner-led businesses where the person who decides also runs delivery.

Two things make this buyer distinctive. They are commercially fluent about exactly what you are selling, because prospecting is their product, so weak claims get dismantled in the first call. And their buying question is margin: does this let a team of eight service ten clients instead of eight, or does it add a subscription without changing capacity. Answer that arithmetic explicitly and you will get further than any feature demonstration.

They are also a channel as much as a customer. An agency that adopts your tool may deploy it across every client account, which makes the deal larger than the seat count suggests, and makes reference-quality onboarding worth more here than almost anywhere else. If you are still choosing a vertical, how to find customers for your startup covers the sequencing.