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Company lists · Data refreshed September 2026

Top 25 Human resources outsourcing companies based in the United States

Compiled by the RevenueBase Data Team Data refreshed Sep 3, 2026 4,436 companies tracked

RevenueBase identified 4,436 human resources outsourcing companies headquartered in the United States as of September 2026 and tracks 96,042 professional contacts across them, including 32,160 with verified work emails and 37,115 with mobile numbers. New York is the largest hub.

This list covers human resources 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
4,436Companies
96,042Contacts tracked
32,160Verified emails
37,115Mobile numbers
Unlock all 4,436 companies Free signup · no credit card · 500 free credits

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

Ranked by team size
Top 25 of 4,436 human resources 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 human resources 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.
#CompanyHeadquartersEmployeesContacts
1
PaychexIndirect evidence
Rochester, NY, United StatesHQ checked Sep 3, 202610001+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
Randstad USAIndirect evidence
Atlanta, GA, United StatesHQ checked Sep 3, 20261,001-5,0008,538

“Randstad North America, Inc.”

Source: company website · checked Sep 3, 2026
3
InsperityIndirect evidence
Kingwood, TX, United StatesHQ checked Sep 3, 20261,001-5,0004,818

“Since 1986, Insperity’s mission has been to help businesses succeed so communities prosper.”

Source: company website · checked Sep 3, 2026
4
TrinetIndirect evidence
Dublin, CA, United StatesHQ checked Sep 3, 20261,001-5,0004,102

“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, 20261,001-5,0003,554

“Gusto has been growing the small business economy for 15+ years.”

Source: company website · checked Sep 3, 2026
6
EclaroIndirect evidence
New York, NY, United StatesHQ checked Sep 3, 20261,001-5,0001,018

“ECLARO is an award-winning Talent Solutions firm headquartered in New York City and operating in the U.S, Canada and the Philippines.”

Source: company website · checked Sep 3, 2026
7
ZimworxStrong evidence
Argyle, TX, United StatesHQ checked Sep 3, 20261,001-5,000697

“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
8
HTIIndirect evidence
Greenville, SC, United StatesHQ checked Sep 3, 20261,001-5,000546

“Industrial Staffing | Professional & Skilled Hourly Recruiting | HR Services | Retention Strategies | Outplacement | Greenfield Start Ups & Expansions | Talent Management At HTI…”

Source: company website · checked Sep 3, 2026
9
HKA EnterprisesIndirect evidence
Duncan, MI, United StatesHQ checked Sep 3, 20261,001-5,000384

“One of the most important aspects of any company is its people.”

Source: company website · checked Sep 3, 2026
10
1840 & CompanyPartial evidence
Overland Park, KS, United StatesHQ checked Sep 3, 20261,001-5,000355

“1840 & Company is a global staffing and outsourcing partner helping U.S.”

Source: company website · checked Sep 3, 2026
11
Managed Labor SolutionsIndirect evidence
Allentown, PA, United StatesHQ checked Sep 3, 20261,001-5,000273

“Managed Labor Solutions (MLS) is a unique provider of outsourced labor to companies large and small.”

Source: company website · checked Sep 3, 2026
12
Staff BoomPartial evidence
Anaheim, CA, United StatesHQ checked Sep 3, 20261,001-5,000241

“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
13
Deploy Hr, INCIndirect evidence
Pleasanton, CA, United StatesHQ checked Sep 3, 20261,001-5,000184
Source: company website · checked Sep 3, 2026
14
Automatic Data ProcessingPartial evidence
Durham, NC, United StatesHQ checked Sep 3, 202610001+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
15
Heartland PayrollIndirect evidence
Rochester, OH, United StatesHQ checked Sep 3, 20261,001-5,000160

“Ovation Payroll is now Heartland Payroll.”

Source: company website · checked Sep 3, 2026
16
NamelyIndirect evidence
Chandler, AZ, United StatesHQ checked Sep 3, 20261,001-5,000151

“Namely is the HR, Payroll, and Benefits platform your employees will love.”

Source: company website · checked Sep 3, 2026
17
Integrity Trade ServicesIndirect evidence
Frankfort, IN, United StatesHQ checked Sep 3, 20265,001-10,000136

“Integrity Trade Services's core philosophy is "Staffing you can trust".”

Source: company website · checked Sep 3, 2026
18
Action Group StaffingIndirect evidence
Tulsa, NJ, United StatesHQ checked Sep 3, 20261,001-5,000114

“Action Group Staffing provides recruiting, staffing and complete HR services: Light Industrial Manufacturing & Assembly, Construction & Skilled Trades, Warehouse & Distribution…”

Source: company website · checked Sep 3, 2026
19
Allsec Technologies LimitedPartial evidence
Irving, TX, United StatesHQ checked Sep 3, 20261,001-5,000104

“Allsec Technologies is a global outsourcing solutions provider, serving over 600 companies in 42+ countries.”

Source: company website · checked Sep 3, 2026
20
Alcott HRIndirect evidence
Farmingdale, NY, United StatesHQ checked Sep 3, 20265,001-10,000102

“At Alcott HR, we have a Passion for People and Performance™.”

Source: company website · checked Sep 3, 2026
21
Infiniti HRStrong evidence
Columbia, AZ, United StatesHQ checked Sep 3, 2026n/a89

“Infiniti HR provides human resources outsourcing services to the small to mid-sized business market, including payroll, human resource compliance, employee benefits services and…”

Source: company website · checked Sep 3, 2026
22
Congruity HRIndirect evidence
Winston-salem, FL, United StatesHQ checked Sep 3, 20265,001-10,00074

“Welcome to Congruity, where we understand that your people are your most valuable asset.”

Source: company website · checked Sep 3, 2026
23
Consolidated Staffing Solutions, INCStrong evidence
Covina, CA, United StatesHQ checked Sep 3, 20261,001-5,00074

“Consolidated Staffing Solutions provides Human Resource Solutions to Companies with demands and requirements of Short Term Placement, Long Term and Permanent Placement, Direct…”

Source: company website · checked Sep 3, 2026
24
Resource Management, INCIndirect evidence
Salt Lake City, WA, United StatesHQ checked Sep 3, 20265,001-10,00072
Source: company website · checked Sep 3, 2026
25
Hospitality Services GroupIndirect evidence
Munster, IN, United StatesHQ checked Sep 3, 20261,001-5,00070

“Hospitality Services Group (HSG) is a premier hospitality company that provides a professional staff for the hospitality industry.”

Source: company website · checked Sep 3, 2026

Showing 25 of 4,436 human resources outsourcing companies based in the United States

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

As of Sep 3, 2026
1-10Median size (employees)
New YorkLargest hub · 121 HQs
37,115Contacts with mobile numbers
Sep 3, 2026Data refreshed

Companies by employee count

1-10
2,838
11-50
1,006
51-200
337
201-500
98
501-1,000
57
1,001-5,000
58
5,001-10,000
15
10001+
16

Verified emails by last verification

0–30
0
31–60
2,713
61–90
18,270
90–180
10,747
180+
430

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 human resources 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 “human resources 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 human resources 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, 32,160 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.

Human resources outsourcing companies by metro

  • Human resources outsourcing companies in New York121
  • Human resources outsourcing companies in Atlanta87
  • Human resources outsourcing companies in Houston80
  • Human resources outsourcing companies in Miami70
  • Human resources outsourcing companies in Los Angeles61
  • Human resources outsourcing companies in Chicago61
  • Human resources outsourcing companies in Dallas53

Frequently asked

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

RevenueBase identified 4,436 human resources 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 human resources outsourcing companies?

New York leads with 121 headquartered companies, followed by Atlanta (87) and Houston (80).

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 32,160 verified decision-maker contacts tracked across these 4,436 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.

Ready to reach these companies? Verified emails and direct dials for all 4,436 human resources outsourcing companies based in the United States. Start with a free account, no credit card.

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Related lists

Browse: Companies home · All United States lists · All Human resources outsourcing companies lists · New lists

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.

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