Company lists · Data refreshed September 2026

Top 25 HR and payroll outsourcing companies based in the United States

RevenueBase identified 3,767 HR and payroll outsourcing companies headquartered in the United States as of September 2026 and tracks 175,397 professional contacts across them, including 63,613 with verified work emails. New York is the largest hub.

This list covers HR and payroll 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 21, 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 21, 2026 86% judged on-target in blind review
3,767Companies
175,397Contacts tracked
63,613Verified emails
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The 25 largest HR and payroll outsourcing companies based in the United States

Ranked by team size
Top 25 of 3,767 HR and payroll outsourcing companies based in the United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to HR and payroll 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidenceRoseland, NJ, United StatesHQ checked Sep 21, 202610001+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 21, 2026
2Strong evidenceRochester, NY, United StatesHQ checked Sep 21, 202610001+17,911 contacts →

Strong 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 21, 2026
3Indirect evidenceKingwood, TX, United StatesHQ checked Sep 21, 20261,001-5,0004,761 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
4Partial evidenceDublin, CA, United StatesHQ checked Sep 21, 20261,001-5,0004,056 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 21, 2026
5Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 21, 20261,001-5,0003,543 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
6Partial evidenceChandler, AZ, United StatesHQ checked Sep 21, 20261,001-5,0002,437 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 21, 2026
7Indirect evidenceVancouver, WA, United StatesHQ checked Sep 21, 2026501-1,0001,591 contacts →

Indirect 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 21, 2026
8Indirect evidenceNew York, NY, United StatesHQ checked Sep 21, 20261,001-5,0001,554 contacts →

Indirect evidence

“Justworks takes the busyness out of growing a business and alleviates the unknown.”

Source: RevenueBase Database · checked Sep 21, 2026
9Indirect evidenceLittleton, CO, United StatesHQ checked Sep 21, 2026n/a1,376 contacts →

Indirect evidence

“Employee Based Systems (EBS) is a innovative HRMS software development, implementation training, support, and services company specializing in helping companies improve…”

Source: RevenueBase Database · checked Sep 21, 2026
10Strong evidenceSeattle, WA, United StatesHQ checked Sep 21, 2026501-1,0001,182 contacts →

Strong evidence

“Keka is a leading unified HR and payroll platform that helps organizations run people operations with consistency, compliance, and operational clarity.”

Source: RevenueBase Database · checked Sep 21, 2026
11Strong evidenceHouston, TX, United StatesHQ checked Sep 21, 2026501-1,000840 contacts →

Strong evidence

“Managing HR, payroll, benefits, and compliance can stretch your team thin, and mistakes are costly.”

Source: RevenueBase Database · checked Sep 21, 2026
12Indirect evidenceWest Palm Beach, FL, United StatesHQ checked Sep 21, 2026501-1,000828 contacts →

Indirect evidence

“Oasis, A Paychex Company, is a leading Professional Employer Organization (PEO).”

Source: RevenueBase Database · checked Sep 21, 2026
13Partial evidenceDallas, TX, United StatesHQ checked Sep 21, 2026501-1,000816 contacts →

Partial evidence

“OneSource Virtual (OSV) delivers patented in-tenant technology and expert services that efficiently automate the administrative, transactional tasks of Workday payroll, taxes…”

Source: RevenueBase Database · checked Sep 21, 2026
14Partial evidencePortland, OR, United StatesHQ checked Sep 21, 2026201-500701 contacts →

Partial evidence

“Trusted by more than 1 million companies, Mineral is the HR and compliance leader for growing businesses.”

Source: RevenueBase Database · checked Sep 21, 2026
15Indirect evidenceAustin, TX, United StatesHQ checked Sep 21, 2026501-1,000665 contacts →

Indirect evidence

“Asure (NASDAQ: ASUR) sees Human Capital Management (HCM) through the lens of entrepreneurs and executives with an owner’s mentality.”

Source: RevenueBase Database · checked Sep 21, 2026
16Strong evidenceHauppauge, NY, United StatesHQ checked Sep 21, 2026n/a655 contacts →

Strong evidence

“Since AccountantsWorld By IRIS is a leader in providing HR and payroll software for accountants and CPA firms.”

Source: RevenueBase Database · checked Sep 21, 2026
17Indirect evidenceBradenton, FL, United StatesHQ checked Sep 21, 2026201-500586 contacts →

Indirect evidence

“CoAdvantage is now CoAd.”

Source: RevenueBase Database · checked Sep 21, 2026
18Indirect evidenceChicago, IL, United StatesHQ checked Sep 21, 2026501-1,000580 contacts →

Indirect evidence

“Atlas HXM understands how people work.”

Source: RevenueBase Database · checked Sep 21, 2026
19Partial evidenceRichfield, OH, United StatesHQ checked Sep 21, 2026501-1,000535 contacts →

Partial evidence

“We provide comprehensive HR solutions to companies of all sizes throughout the United States.”

Source: RevenueBase Database · checked Sep 21, 2026
20Indirect evidenceWichita, KS, United StatesHQ checked Sep 21, 2026501-1,000525 contacts →

Indirect evidence

“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.”

Source: RevenueBase Database · checked Sep 21, 2026
21Partial evidenceIrving, TX, United StatesHQ checked Sep 21, 202651-200496 contacts →

Partial evidence

“For over 35 years, MMC has been a trusted leader in Staffing and Payroll solutions, serving the private, public, and federal sectors with unparalleled excellence.”

Source: RevenueBase Database · checked Sep 21, 2026
22Strong evidenceChandler, AZ, United StatesHQ checked Sep 21, 2026201-500436 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 21, 2026
23Partial evidenceHonolulu, HI, United StatesHQ checked Sep 21, 2026201-500421 contacts →

Partial evidence

“ProService Hawaii provides bundled HR solutions that make it easier for employers to succeed.”

Source: RevenueBase Database · checked Sep 21, 2026
24Strong evidenceClearwater, FL, United StatesHQ checked Sep 21, 2026201-500383 contacts →

Strong 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 21, 2026
25Strong evidenceRaleigh, NC, United StatesHQ checked Sep 21, 2026n/a381 contacts →

Strong evidence

“Headway Workforce Solutions is a leading B2B (Business to Business) provider of HR Administration Outsourcing and Talent Solutions.”

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 3,767 HR and payroll outsourcing companies based in the United States

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HR and payroll outsourcing companies based in the United States at a glance

As of Sep 21, 2026
36.3%Verified-email coverage
46.6Average contacts per company
1-10Median size (employees)
2.0%Largest-city concentration · New York
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
2,240
11-50
963
51-200
335
201-500
93
501-1,000
47
1,001-5,000
47
5,001-10,000
15
10001+
20

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 3,767 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 HR and payroll 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 and payroll 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 and payroll 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 and payroll 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, 63,613 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 21, 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.

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 and payroll 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 and payroll outsourcing companies are there based in the United States?

RevenueBase identified 3,767 HR and payroll 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 HR and payroll outsourcing companies?

New York leads with 76 headquartered companies, followed by Houston (65) and Atlanta (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 63,613 verified decision-maker contacts tracked across these 3,767 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 21, 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.