Company lists · Data refreshed September 2026

Top 25 Human resources outsourcing firms based in the United States

Name: Human resources outsourcing firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 28, 2026 5,599 companies tracked

RevenueBase identified 5,599 company matches for human resources outsourcing firms associated with the United States as of September 2026 and tracks 208,516 professional contacts across them, including 67,371 with verified work emails. New York is the largest hub.

This list covers company matches for human resources outsourcing firms associated with the United States, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed September 28, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, 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.

How to read this list RevenueBase SmartSearch · Exact Recorded Sep 28, 2026 How this list was built

5,599Companies

208,516Contacts tracked

67,371Verified emails

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The 25 largest human resources outsourcing firms based in the United States

Ranked by team size

Top 25 of 5,599 company matches for human resources outsourcing firms based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 28, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#	Company	RevenueBase SmartSearch	Headquarters	Employees	Contacts
1	ADP	Exact match	Roseland, NJ, United StatesHQ recorded Sep 28, 2026	10001+	84,166 contacts →
	Exact match “Designing better ways to work through cutting-edge products, premium services and exceptional experiences that enable people to reach their full potential.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
2	Paychex	Exact match	Rochester, NY, United StatesHQ recorded Sep 28, 2026	10001+	17,911 contacts →
	Exact match “As the future of work continues to evolve, Paychex leads the way by making complex HR, payroll, and benefits brilliantly simple.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
3	LHH	Exact match	Jacksonville, FL, United StatesHQ recorded Sep 28, 2026	10001+	12,889 contacts →
	Exact match “At LHH, we believe work should be meaningful, fulfilling, and connected.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
4	Randstad USA	Exact match	Atlanta, GA, United StatesHQ recorded Sep 28, 2026	1,001-5,000	8,522 contacts →
	Exact match “Randstad North America, Inc.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
5	Insperity	Exact match	Kingwood, TX, United StatesHQ recorded Sep 28, 2026	1,001-5,000	4,761 contacts →
	Exact match “Since 1986, Insperity’s mission has been to help businesses succeed so communities prosper.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
6	Trinet	Exact match	Dublin, CA, United StatesHQ recorded Sep 28, 2026	1,001-5,000	4,056 contacts →
	Exact match “TriNet (NYSE: TNET) provides small and medium-size businesses (SMBs) with full-service HR solutions tailored by industry.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
7	PSG Global Solutions	Exact match	Marina Del Rey, CA, United StatesHQ recorded Sep 28, 2026	1,001-5,000	4,000 contacts →
	Exact match “PSG is a global leader in recruitment process optimization, delivering high-performance outsourced recruiting solutions that drive real business results.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
8	GUSTO	Exact match	San Francisco, CA, United StatesHQ recorded Sep 28, 2026	1,001-5,000	3,543 contacts →
	Exact match “Gusto has been growing the small business economy for 15+ years.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
9	Allegis Global Solutions	Exact match	Hanover, MD, United StatesHQ recorded Sep 28, 2026	1,001-5,000	2,866 contacts →
	Exact match “At Allegis Global Solutions (AGS), we’re in the human enterprise business.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
10	247hire	Exact match	Oak Brook, IL, United StatesHQ recorded Sep 28, 2026	201-500	1,059 contacts →
	Exact match “At 247Hire, our mission is simple: to empower yours.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
11	Eclaro	Exact match	New York, NY, United StatesHQ recorded Sep 28, 2026	1,001-5,000	1,024 contacts →
	Exact match “ECLARO is an award-winning Talent Solutions firm headquartered in New York City and operating in the U.S, Canada and the Philippines.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
12	G&a Partners	Exact match	Houston, TX, United StatesHQ recorded Sep 28, 2026	501-1,000	840 contacts →
	Exact match “Managing HR, payroll, benefits, and compliance can stretch your team thin, and mistakes are costly.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
13	OASIS	Exact match	West Palm Beach, FL, United StatesHQ recorded Sep 28, 2026	501-1,000	828 contacts →
	Exact match “Oasis, A Paychex Company, is a leading Professional Employer Organization (PEO).” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
14	Mineral, Part Of Mitratech	Exact match	Portland, OR, United StatesHQ recorded Sep 28, 2026	201-500	701 contacts →
	Exact match “Trusted by more than 1 million companies, Mineral is the HR and compliance leader for growing businesses.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
15	EOX Vantage	Exact match	Cleveland, OH, United StatesHQ recorded Sep 28, 2026	501-1,000	654 contacts →
	Exact match “For over two decades, EOX Vantage has specialized in providing scalable, on-demand support to aid our partners with their current workforce challenges and ensure that their agents…” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
16	Coadvantage	Exact match	Bradenton, FL, United StatesHQ recorded Sep 28, 2026	201-500	586 contacts →
	Exact match “CoAdvantage is now CoAd.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
17	HTI	Exact match	Greenville, SC, United StatesHQ recorded Sep 28, 2026	1,001-5,000	553 contacts →
	Exact match “Industrial Staffing \| Professional & Skilled Hourly Recruiting \| HR Services \| Retention Strategies \| Outplacement \| Greenfield Start Ups & Expansions \| Talent Management At HTI…” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
18	Group Management Services, INC	Exact match	Richfield, OH, United StatesHQ recorded Sep 28, 2026	501-1,000	535 contacts →
	Exact match “We provide comprehensive HR solutions to companies of all sizes throughout the United States.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
19	Infosync	Exact match	Wichita, KS, United StatesHQ recorded Sep 28, 2026	501-1,000	525 contacts →
	Exact match “In today's fast-paced business landscape, multi-unit companies demand more than just basic operations-they need expert guidance and cutting-edge technology to thrive.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
20	Pride Global	Exact match	New York, NY, United StatesHQ recorded Sep 28, 2026	1,001-5,000	448 contacts →
	Exact match “Pride Global is a minority-owned integrated human capital solutions & advisory firm headquartered in New York with operating companies throughout the United States, United…” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
21	Prismhr	Exact match	Chandler, AZ, United StatesHQ recorded Sep 28, 2026	201-500	436 contacts →
	Exact match “PrismHR creates exceptional software and services, empowering human resource outsourcing service providers such as Professional Employer Organizations (PEOs) and HR outsourcers to…” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
22	Anywhere	Exact match	Silicon Valley, CA, United StatesHQ recorded Sep 28, 2026	n/a	435 contacts →
	Exact match “Nós nascemos no Vale do Silício e aqui aprendemos técnicas inovadoras sobre como fazer Talent Acquisition de uma forma estratégica e que gere impacto no negócio, nós não só…” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
23	Proservice Hawaii	Exact match	Honolulu, HI, United StatesHQ recorded Sep 28, 2026	201-500	421 contacts →
	Exact match “ProService Hawaii provides bundled HR solutions that make it easier for employers to succeed.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
24	HR Personnel Services	Exact match	Minnetonka, MN, United StatesHQ recorded Sep 28, 2026	n/a	402 contacts →
	Exact match “HR Personnel Services is a leading national staffing and executive search firm specializing exclusively in placing HR professionals.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
25	Frankcrum	Exact match	Clearwater, FL, United StatesHQ recorded Sep 28, 2026	201-500	383 contacts →
	Exact match “FrankCrum offers outsourced HR, payroll and payroll administration, employee benefits and benefits administration, 401(k), workers compensation and HR Solutions.” Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase

RevenueBase SmartSearch

Describe a niche business in your own words. RevenueBase SmartSearch compares the meaning of your description with company business descriptions compiled in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit.

This list uses Exact for “human resources outsourcing firms”. Each Exact match badge shows membership in that saved search; it is not an individual similarity score or a service-quality rating. Recorded descriptions are shown where available.

Showing 25 of 5,599 human resources outsourcing firms based in the United States

See the full list, filter by size, metro and specialty, and access 67,371 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Human resources outsourcing firms based in the United States at a glance

As of Sep 28, 2026

32.3%Verified-email coverage

37.2Average contacts per company

1-10Median size (employees)

3.3%Largest-city concentration · New York

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

3,744

11-50

1,159

51-200

395

201-500

118

501-1,000

1,001-5,000

5,001-10,000

10001+

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 5,599 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies: Company records associated with the United States whose business descriptions match “human resources outsourcing firms” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch: Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview: The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality: RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
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 displayed company carries at least one verified work email. RevenueBase tracks 67,371 professional contacts with verified work emails across the full matched dataset. 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.
Record context: Company records and descriptions can change. Check the company's website for its current services and locations.

Human resources outsourcing firms by metro

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “human resources outsourcing firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many human resources outsourcing firms are there based in the United States?

RevenueBase identified 5,599 company matches for human resources outsourcing firms associated with the United States as of September 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

ADP tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city has the most human resources outsourcing firms?

New York leads with 186 company records, followed by Atlanta (129) and Houston (107).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 67,371 professional contacts with verified work emails tracked across these 5,599 companies; direct dials are available where recorded.

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.

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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 SmartSearch, 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.