Company lists · Data refreshed September 2026

Top 25 HR outsourcing companies based in the United States

Name: HR outsourcing companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 3, 2026 7,071 companies tracked

RevenueBase identified 7,071 HR outsourcing companies headquartered in the United States as of September 2026 and tracks 188,107 professional contacts across them, including 49,078 with verified work emails and 59,584 with mobile numbers. New York is the largest hub.

This list covers HR 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, how directly it supports the match, and when it was last checked. Data refreshed September 3, 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 HQ checked on every row Match evidence on every row Refreshed Sep 3, 2026 86% judged on-target in blind review

7,071Companies

188,107Contacts tracked

49,078Verified emails

59,584Mobile numbers

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The 25 largest HR outsourcing companies based in the United States

Ranked by team size

Top 25 of 7,071 HR outsourcing companies based in the United States, ranked by team size, largest first. Data refreshed Sep 3, 2026. Evidence rates how directly each company's own description names HR outsourcing companies: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#	Company	Headquarters	Employees	Contacts
1	PaychexPartial evidence	Rochester, NY, United StatesHQ checked Sep 3, 2026	10001+	17,921
	“As the future of work continues to evolve, Paychex leads the way by making complex HR, payroll, and benefits brilliantly simple.” Source: company website · checked Sep 3, 2026
2	Express Employment InternationalIndirect evidence	Oklahoma City, OK, United StatesHQ checked Sep 3, 2026	10001+	12,667
	“Founded in 1983 and corporately headquartered in Oklahoma City, Express Employment International supports the Express Employment Professionals franchise and related brands.” Source: company website · checked Sep 3, 2026
3	StradaIndirect evidence	The Woodlands, TX, United StatesHQ checked Sep 3, 2026	5,001-10,000	5,553
	“With over 30 years as a global people, payroll, and technology leader, Strada specializes in removing complexity to simplify workforce management.” Source: company website · checked Sep 3, 2026
4	TrinetPartial evidence	Dublin, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	4,102
	“TriNet (NYSE: TNET) provides small and medium-size businesses (SMBs) with full-service HR solutions tailored by industry.” Source: company website · checked Sep 3, 2026
5	GUSTOIndirect evidence	San Francisco, CO, United StatesHQ checked Sep 3, 2026	1,001-5,000	3,554
	“Gusto has been growing the small business economy for 15+ years.” Source: company website · checked Sep 3, 2026
6	Remedy Intelligent StaffingIndirect evidence	Atlanta, GA, United StatesHQ checked Sep 3, 2026	10001+	1,948
	“Remedy Intelligent Staffing is a nationwide professional staffing organization with more than 50 years of recruiting and selection expertise to match job candidates with positions…” Source: company website · checked Sep 3, 2026
7	Office Beacon LLCIndirect evidence	Redondo Beach, CA, United StatesHQ checked Sep 3, 2026	5,001-10,000	1,392
	“For 25 years, Office Beacon has helped companies scale smarter by providing fully managed remote staffing across every department, in every major industry.” Source: company website · checked Sep 3, 2026
8	System ONEIndirect evidence	Pittsburgh, IN, United StatesHQ checked Sep 3, 2026	5,001-10,000	1,380
	“System One is a leading provider of specialized, highly technical outsourced services, workforce solutions, staffing, and recruiting to critical infrastructure, technology, life…” Source: company website · checked Sep 3, 2026
9	SEBPOIndirect evidence	Marlton, NJ, United StatesHQ checked Sep 3, 2026	1,001-5,000	1,249
	“SEBPO transforms operational complexity into a seamless, strategic advantage.” Source: company website · checked Sep 3, 2026
10	PeoplescoutIndirect evidence	Chicago, IL, United StatesHQ checked Sep 3, 2026	1,001-5,000	1,176
	“PeopleScout, a TrueBlue company, is a global talent solutions leader.” Source: company website · checked Sep 3, 2026
11	ZimworxPartial evidence	Argyle, TX, United StatesHQ checked Sep 3, 2026	1,001-5,000	697
	“ZimWorX is a human resources & outsourcing company that helps companies find the best remote employees for their business and field.” Source: company website · checked Sep 3, 2026
12	Acara Solutions, An Aleron CompanyIndirect evidence	Buffalo, NY, United StatesHQ checked Sep 3, 2026	5,001-10,000	486
	“Acara is a premier provider of recruiting and workforce solutions-we help companies compete for talent.” Source: company website · checked Sep 3, 2026
13	Apidel TechnologiesIndirect evidence	Plainfield, IL, United StatesHQ checked Sep 3, 2026	5,001-10,000	432
	“Apidel is a WMBE (Women & Minority Based Enterprise) & E-verified Global Staffing company.” Source: company website · checked Sep 3, 2026
14	HKA EnterprisesIndirect evidence	Duncan, MI, United StatesHQ checked Sep 3, 2026	1,001-5,000	384
	“One of the most important aspects of any company is its people.” Source: company website · checked Sep 3, 2026
15	IntelassistIndirect evidence	South San Francisco, WA, United StatesHQ checked Sep 3, 2026	1,001-5,000	362
	“Established in 2007, Intelassist is a remote staffing organization, beginning as a partnership between US-based industry professionals and an experienced operational team in…” Source: company website · checked Sep 3, 2026
16	1840 & CompanyPartial evidence	Overland Park, KS, United StatesHQ checked Sep 3, 2026	1,001-5,000	355
	“1840 & Company is a global staffing and outsourcing partner helping U.S.” Source: company website · checked Sep 3, 2026
17	Ics, A Korn Ferry CompanyIndirect evidence	New York, OH, United StatesHQ checked Sep 3, 2026	1,001-5,000	350
	“ICS, a Korn Ferry Company, is one of the nation’s leading staffing and recruiting companies specializing in connecting talented people to the businesses who need them.” Source: company website · checked Sep 3, 2026
18	MY Mountain MoverIndirect evidence	Orange, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	302
	“Transforming Businesses with Top Virtual Talent.” Source: company website · checked Sep 3, 2026
19	Volt Information SciencesIndirect evidence	New York, CA, United StatesHQ checked Sep 3, 2026	5,001-10,000	290
	“Volt is a global provider of talent, technology and consulting services.” Source: company website · checked Sep 3, 2026
20	Full Steam StaffingIndirect evidence	Ontario, CA, United StatesHQ checked Sep 3, 2026	5,001-10,000	288
	“Full Steam Staffing LLC is a privately owned national leader in providing recruitment, staffing, and human resources solutions.” Source: company website · checked Sep 3, 2026
21	Managed Labor SolutionsIndirect evidence	Allentown, PA, United StatesHQ checked Sep 3, 2026	1,001-5,000	273
	“Managed Labor Solutions (MLS) is a unique provider of outsourced labor to companies large and small.” Source: company website · checked Sep 3, 2026
22	Staff BoomIndirect evidence	Anaheim, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	241
	“Staff Boom specializes in customized staffing solutions and consulting for small and medium sized businesses to save money and resources, improve how they work and prevent…” Source: company website · checked Sep 3, 2026
23	NextsourceIndirect evidence	New York, TN, United StatesHQ checked Sep 3, 2026	1,001-5,000	234
	“It’s important to know who you’re partnering with.” Source: company website · checked Sep 3, 2026
24	Deploy Hr, INCIndirect evidence	Pleasanton, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	184
	Source: company website · checked Sep 3, 2026
25	Automatic Data ProcessingPartial evidence	Durham, NC, United StatesHQ checked Sep 3, 2026	10001+	174
	“ADP is a comprehensive global provider of cloud-based human capital management (HCM) solutions that unite HR, payroll, talent, time, tax and benefits administration, and a leader…” Source: company website · checked Sep 3, 2026

Showing 25 of 7,071 HR outsourcing companies based in the United States

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HR outsourcing companies based in the United States at a glance

As of Sep 3, 2026

1-10Median size (employees)

New YorkLargest hub · 245 HQs

59,584Contacts with mobile numbers

Sep 3, 2026Data refreshed

Companies by employee count

1-10

4,242

11-50

1,701

51-200

678

201-500

198

501-1,000

1,001-5,000

5,001-10,000

10001+

Verified emails by last verification

0–30

31–60

4,240

61–90

27,836

90–180

16,449

180+

553

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 HR outsourcing companies, so some rows will be adjacent to the category rather than pure plays. The description and evidence 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 SmartSearch, 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 “HR outsourcing companies”. Matching reads each company's description, not its industry code or its name.
What we exclude: Companies whose own description does not clearly place them among HR 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 an evidence 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, 49,078 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 3, 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.

HR outsourcing companies by metro

HR outsourcing companies in New York245
HR outsourcing companies in Atlanta153
HR outsourcing companies in Houston136
HR outsourcing companies in Los Angeles126
HR outsourcing companies in Miami115
HR outsourcing companies in Chicago106
HR outsourcing companies in Dallas101

Frequently asked

How many HR outsourcing companies are there based in the United States?

RevenueBase identified 7,071 HR 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?

Paychex, headquartered in Rochester, tops this list with the largest team on record.

Which city has the most HR outsourcing companies?

New York leads with 245 headquartered companies, followed by Atlanta (153) and Houston (136).

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 49,078 verified decision-maker contacts tracked across these 7,071 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 3, 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.