Company lists · Data refreshed September 2026
Top 25 Employee relations outsourcing companies based in the United States
RevenueBase identified 3,857 employee relations outsourcing companies headquartered in the United States as of September 2026 and tracks 156,501 professional contacts across them, including 52,327 with verified work emails. New York is the largest hub.
This list covers employee relations outsourcing companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 28, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest employee relations outsourcing companies based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 84,166 contacts → | ||||
Indirect evidence “Designing better ways to work through cutting-edge products, premium services and exceptional experiences that enable people to reach their full potential.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 2 | 8,522 contacts → | ||||
Indirect evidence “Randstad North America, Inc.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 3 | 4,761 contacts → | ||||
Indirect evidence “Since 1986, Insperity’s mission has been to help businesses succeed so communities prosper.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 4 | 4,056 contacts → | ||||
Indirect evidence “TriNet (NYSE: TNET) provides small and medium-size businesses (SMBs) with full-service HR solutions tailored by industry.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 5 | 2,866 contacts → | ||||
Indirect evidence “At Allegis Global Solutions (AGS), we’re in the human enterprise business.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 6 | 2,437 contacts → | ||||
Partial evidence “VensureHR is the direct employer services business unit of Vensure Employer Solutions, the largest privately held organization in the HR technology and services sector, delivering…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 7 | 1,591 contacts → | ||||
Partial evidence “We started as a staffing company in 1972, and over the past 50 years, evolved into a Professional Employer Organization or PEO.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 8 | 1,430 contacts → | ||||
Indirect evidence “Hiring someone in another country shouldn't mean months of legal setup and compliance risk in a jurisdiction you’re not familiar with.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 9 | 1,024 contacts → | ||||
Indirect evidence “ECLARO is an award-winning Talent Solutions firm headquartered in New York City and operating in the U.S, Canada and the Philippines.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 10 | 840 contacts → | ||||
Indirect evidence “Managing HR, payroll, benefits, and compliance can stretch your team thin, and mistakes are costly.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 11 | 828 contacts → | ||||
Partial evidence “Oasis, A Paychex Company, is a leading Professional Employer Organization (PEO).” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 12 | 792 contacts → | ||||
Partial evidence “Global employer of record (EOR) and agent of record (AOR) services, exclusively for the talent procurement sector.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 13 | 586 contacts → | ||||
Indirect evidence “CoAdvantage is now CoAd.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 14 | 553 contacts → | ||||
Indirect evidence “Industrial Staffing | Professional & Skilled Hourly Recruiting | HR Services | Retention Strategies | Outplacement | Greenfield Start Ups & Expansions | Talent Management At HTI…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 15 | 535 contacts → | ||||
Indirect evidence “We provide comprehensive HR solutions to companies of all sizes throughout the United States.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 16 | 480 contacts → | ||||
Indirect evidence “Founded in 2008, PACER is a Minority Woman-owned Global Staffing firm serving Fortune 500 Clients with customized and scalable workforce solutions.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 17 | 436 contacts → | ||||
Strong evidence “PrismHR creates exceptional software and services, empowering human resource outsourcing service providers such as Professional Employer Organizations (PEOs) and HR outsourcers to…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 18 | 383 contacts → | ||||
Partial evidence “FrankCrum offers outsourced HR, payroll and payroll administration, employee benefits and benefits administration, 401(k), workers compensation and HR Solutions.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 19 | 382 contacts → | ||||
Indirect evidence “One of the most important aspects of any company is its people.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 20 | 381 contacts → | ||||
Partial evidence “Headway Workforce Solutions is a leading B2B (Business to Business) provider of HR Administration Outsourcing and Talent Solutions.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 21 | 353 contacts → | ||||
Partial evidence “ExtensisHR, one of the largest Professional Employer Organizations (PEOs) in the U.S, is looking for talented people to join our team!” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 22 | 341 contacts → | ||||
Indirect evidence “Engage PEO delivers comprehensive HR solutions to small and medium-sized businesses, sharpening their competitive advantage.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 23 | 341 contacts → | ||||
Indirect evidence “Most founders don't start a business because they love navigating HR compliance, filing payroll taxes, or negotiating healthcare premiums.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 24 | 334 contacts → | ||||
Indirect evidence “Somos parte de ARCH Resources Group, un conglomerado líder en el desarrollo de soluciones en Recursos Humanos, con presencia en 12 países del continente.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 25 | 332 contacts → | ||||
Partial evidence “IntelliSource continues to redefine the outsourcing space through our breadth of experience, unique personality, and fresh approach to problem-solving, which is integrated into…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: employee relations outsourcing companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names employee relations outsourcing companies.
- Partial evidence
- Its own public description names part of employee relations outsourcing companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name employee relations outsourcing companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 3,857 employee relations outsourcing companies based in the United States
See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 52,327 reachable decision-makers.
Free signup · no credit card
Employee relations outsourcing companies based in the United States at a glance
As of Sep 28, 2026Companies by employee count
Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 3,857 companies.
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among employee relations outsourcing companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- What qualifies
- Companies headquartered in the United States whose own description of what they do matches “employee relations outsourcing companies”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names employee relations outsourcing companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among employee relations outsourcing companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 52,327 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 28, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Employee relations outsourcing companies by metro
- Employee relations outsourcing companies in New York123
- Employee relations outsourcing companies in Atlanta68
- Employee relations outsourcing companies in Houston62
- Employee relations outsourcing companies in Los Angeles57
- Employee relations outsourcing companies in Chicago49
- Employee relations outsourcing companies in Austin47
- Employee relations outsourcing companies in Miami47
- Employee relations outsourcing companies in San Diego47
- Employee relations outsourcing companies in Dallas41
- Employee relations outsourcing companies in San Francisco39
- Employee relations outsourcing companies in Denver35
- Employee relations outsourcing companies in Phoenix34
- Employee relations outsourcing companies in Tampa33
- Employee relations outsourcing companies in Charlotte31
- Employee relations outsourcing companies in Washington31
- Employee relations outsourcing companies in Orlando29
- Employee relations outsourcing companies in Boston28
- Employee relations outsourcing companies in San Antonio28
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names employee relations outsourcing companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many employee relations outsourcing companies are there based in the United States?
RevenueBase identified 3,857 employee relations outsourcing companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
ADP, headquartered in Roseland, tops this list with the largest team on record.
Which city has the most employee relations outsourcing companies?
New York leads with 123 headquartered companies, followed by Atlanta (68) and Houston (62).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 52,327 verified decision-maker contacts tracked across these 3,857 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 28, 2026.
Ready to reach these companies? Verified emails and direct dials for all 3,857 employee relations outsourcing companies based in the United States. Start with a free account, no credit card.
Download this list →Related lists
Employee relations outsourcing companies by geography
- Employee relations outsourcing companies based in Brisbane, Australia
- Employee relations outsourcing companies based in Melbourne, Australia
- Employee relations outsourcing companies based in Perth, Australia
- Employee relations outsourcing companies based in Sydney, Australia
- Employee relations outsourcing companies based in Belo Horizonte, Brazil
- Employee relations outsourcing companies based in Campinas, Brazil
- Employee relations outsourcing companies based in Curitiba, Brazil
- Employee relations outsourcing companies based in Porto Alegre, Brazil
- Employee relations outsourcing companies based in Rio De Janeiro, Brazil
- Employee relations outsourcing companies based in Sao Paulo, Brazil
- Employee relations outsourcing companies based in Calgary, Canada
- Employee relations outsourcing companies based in Edmonton, Canada
About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.
More company lists
- All company lists
- Lists by location
- Lists A-Z
- New lists
- Employee relations outsourcing companies based in Brisbane, Australia
- Employee relations outsourcing companies based in Melbourne, Australia
- Employee relations outsourcing companies based in Perth, Australia
- Employee relations outsourcing companies based in Sydney, Australia
- Employee relations outsourcing companies based in Belo Horizonte, Brazil
- Employee relations outsourcing companies based in Campinas, Brazil