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, its RevenueBase Smart Search rating, 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 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating 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. RevenueBase Smart Search rates how each company's information relates to HR outsourcing companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Paychex	Partial evidence	Rochester, NY, United StatesHQ checked Sep 3, 2026	10001+	17,921 contacts →
	Partial evidence “As the future of work continues to evolve, Paychex leads the way by making complex HR, payroll, and benefits brilliantly simple.” Source: RevenueBase Database · checked Sep 3, 2026
2	Express Employment International	Indirect evidence	Oklahoma City, OK, United StatesHQ checked Sep 3, 2026	10001+	12,667 contacts →
	Indirect evidence “Founded in 1983 and corporately headquartered in Oklahoma City, Express Employment International supports the Express Employment Professionals franchise and related brands.” Source: RevenueBase Database · checked Sep 3, 2026
3	Strada	Indirect evidence	The Woodlands, TX, United StatesHQ checked Sep 3, 2026	5,001-10,000	5,553 contacts →
	Indirect evidence “With over 30 years as a global people, payroll, and technology leader, Strada specializes in removing complexity to simplify workforce management.” Source: RevenueBase Database · checked Sep 3, 2026
4	Trinet	Partial evidence	Dublin, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	4,102 contacts →
	Partial evidence “TriNet (NYSE: TNET) provides small and medium-size businesses (SMBs) with full-service HR solutions tailored by industry.” Source: RevenueBase Database · checked Sep 3, 2026
5	GUSTO	Indirect evidence	San Francisco, CO, United StatesHQ checked Sep 3, 2026	1,001-5,000	3,554 contacts →
	Indirect evidence “Gusto has been growing the small business economy for 15+ years.” Source: RevenueBase Database · checked Sep 3, 2026
6	Remedy Intelligent Staffing	Indirect evidence	Atlanta, GA, United StatesHQ checked Sep 3, 2026	10001+	1,948 contacts →
	Indirect evidence “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: RevenueBase Database · checked Sep 3, 2026
7	Office Beacon LLC	Indirect evidence	Redondo Beach, CA, United StatesHQ checked Sep 3, 2026	5,001-10,000	1,392 contacts →
	Indirect evidence “For 25 years, Office Beacon has helped companies scale smarter by providing fully managed remote staffing across every department, in every major industry.” Source: RevenueBase Database · checked Sep 3, 2026
8	System ONE	Indirect evidence	Pittsburgh, IN, United StatesHQ checked Sep 3, 2026	5,001-10,000	1,380 contacts →
	Indirect evidence “System One is a leading provider of specialized, highly technical outsourced services, workforce solutions, staffing, and recruiting to critical infrastructure, technology, life…” Source: RevenueBase Database · checked Sep 3, 2026
9	SEBPO	Indirect evidence	Marlton, NJ, United StatesHQ checked Sep 3, 2026	1,001-5,000	1,249 contacts →
	Indirect evidence “SEBPO transforms operational complexity into a seamless, strategic advantage.” Source: RevenueBase Database · checked Sep 3, 2026
10	Peoplescout	Indirect evidence	Chicago, IL, United StatesHQ checked Sep 3, 2026	1,001-5,000	1,176 contacts →
	Indirect evidence “PeopleScout, a TrueBlue company, is a global talent solutions leader.” Source: RevenueBase Database · checked Sep 3, 2026
11	Zimworx	Partial evidence	Argyle, TX, United StatesHQ checked Sep 3, 2026	1,001-5,000	697 contacts →
	Partial evidence “ZimWorX is a human resources & outsourcing company that helps companies find the best remote employees for their business and field.” Source: RevenueBase Database · checked Sep 3, 2026
12	Acara Solutions, An Aleron Company	Indirect evidence	Buffalo, NY, United StatesHQ checked Sep 3, 2026	5,001-10,000	486 contacts →
	Indirect evidence “Acara is a premier provider of recruiting and workforce solutions-we help companies compete for talent.” Source: RevenueBase Database · checked Sep 3, 2026
13	Apidel Technologies	Indirect evidence	Plainfield, IL, United StatesHQ checked Sep 3, 2026	5,001-10,000	432 contacts →
	Indirect evidence “Apidel is a WMBE (Women & Minority Based Enterprise) & E-verified Global Staffing company.” Source: RevenueBase Database · checked Sep 3, 2026
14	HKA Enterprises	Indirect evidence	Duncan, MI, United StatesHQ checked Sep 3, 2026	1,001-5,000	384 contacts →
	Indirect evidence “One of the most important aspects of any company is its people.” Source: RevenueBase Database · checked Sep 3, 2026
15	Intelassist	Indirect evidence	South San Francisco, WA, United StatesHQ checked Sep 3, 2026	1,001-5,000	362 contacts →
	Indirect evidence “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: RevenueBase Database · checked Sep 3, 2026
16	1840 & Company	Partial evidence	Overland Park, KS, United StatesHQ checked Sep 3, 2026	1,001-5,000	355 contacts →
	Partial evidence “1840 & Company is a global staffing and outsourcing partner helping U.S.” Source: RevenueBase Database · checked Sep 3, 2026
17	Ics, A Korn Ferry Company	Indirect evidence	New York, OH, United StatesHQ checked Sep 3, 2026	1,001-5,000	350 contacts →
	Indirect evidence “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: RevenueBase Database · checked Sep 3, 2026
18	MY Mountain Mover	Indirect evidence	Orange, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	302 contacts →
	Indirect evidence “Transforming Businesses with Top Virtual Talent.” Source: RevenueBase Database · checked Sep 3, 2026
19	Volt Information Sciences	Indirect evidence	New York, CA, United StatesHQ checked Sep 3, 2026	5,001-10,000	290 contacts →
	Indirect evidence “Volt is a global provider of talent, technology and consulting services.” Source: RevenueBase Database · checked Sep 3, 2026
20	Full Steam Staffing	Indirect evidence	Ontario, CA, United StatesHQ checked Sep 3, 2026	5,001-10,000	288 contacts →
	Indirect evidence “Full Steam Staffing LLC is a privately owned national leader in providing recruitment, staffing, and human resources solutions.” Source: RevenueBase Database · checked Sep 3, 2026
21	Managed Labor Solutions	Indirect evidence	Allentown, PA, United StatesHQ checked Sep 3, 2026	1,001-5,000	273 contacts →
	Indirect evidence “Managed Labor Solutions (MLS) is a unique provider of outsourced labor to companies large and small.” Source: RevenueBase Database · checked Sep 3, 2026
22	Staff Boom	Indirect evidence	Anaheim, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	241 contacts →
	Indirect evidence “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: RevenueBase Database · checked Sep 3, 2026
23	Nextsource	Indirect evidence	New York, TN, United StatesHQ checked Sep 3, 2026	1,001-5,000	234 contacts →
	Indirect evidence “It’s important to know who you’re partnering with.” Source: RevenueBase Database · checked Sep 3, 2026
24	Deploy Hr, INC	Indirect evidence	Pleasanton, CA, United StatesHQ checked Sep 3, 2026	1,001-5,000	184 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 3, 2026
25	Automatic Data Processing	Partial evidence	Durham, NC, United StatesHQ checked Sep 3, 2026	10001+	174 contacts →
	Partial evidence “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: RevenueBase Database · checked Sep 3, 2026

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: HR 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 HR outsourcing companies.
Partial evidence: Its own public description names part of HR outsourcing companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name HR 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 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

26.1%Verified-email coverage

31.7%Mobile-number coverage

26.6Average contacts per company

1-10Median size (employees)

3.5%Largest-city concentration · New York

Sep 3, 2026Page data 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+

Freshness & accuracy

How recently the business emails on this list were verified

Email last verified

00–30

4,24031–60

27,83661–90

16,44990–180

553180+

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 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 “HR 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 HR 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 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 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, 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

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 HR 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 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 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.