Company lists · Data refreshed September 2026

Top 25 Core administrative processing systems software companies based in the United States

RevenueBase identified 420 core administrative processing systems software companies headquartered in the United States as of September 2026 and tracks 137,999 professional contacts across them, including 49,724 with verified work emails. New York is the largest hub.

This list covers core administrative processing systems software 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 14, 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 14, 2026 86% judged on-target in blind review
420Companies
137,999Contacts tracked
49,724Verified emails
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The 25 largest core administrative processing systems software companies based in the United States

Ranked by team size
Top 25 of 420 core administrative processing systems software companies based in the United States, ranked by team size, largest first. Data refreshed Sep 14, 2026. RevenueBase Smart Search rates how each company's information relates to core administrative processing systems software 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 14, 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 14, 2026
2Indirect evidenceRochester, NY, United StatesHQ checked Sep 14, 202610001+17,911 contacts →

Indirect 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 14, 2026
3Partial evidenceOklahoma City, OK, United StatesHQ checked Sep 14, 20265,001-10,0007,002 contacts →

Partial evidence

“Paycom (NYSE:PAYC) automates the entire employee life cycle in a truly single HR and payroll software.”

Source: RevenueBase Database · checked Sep 14, 2026
4Partial evidenceSchaumburg, IL, United StatesHQ checked Sep 14, 20265,001-10,0006,153 contacts →

Partial evidence

“Paylocity (NASDAQ: PCTY) is an award-winning provider of cloud-based HR, payroll and spend management software solutions.”

Source: RevenueBase Database · checked Sep 14, 2026
5Indirect evidenceThe Woodlands, TX, United StatesHQ checked Sep 14, 20265,001-10,0005,585 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 14, 2026
6Partial evidenceCentennial, CO, United StatesHQ checked Sep 14, 20261,001-5,0002,363 contacts →

Partial evidence

“For 25+ years, we’ve transformed the way government agencies serve their communities, providing software that delivers superior customer experiences, greater flexibility, and…”

Source: RevenueBase Database · checked Sep 14, 2026
7Partial evidenceLowell, MA, United StatesHQ checked Sep 14, 20265,001-10,0001,889 contacts →

Partial evidence

“Built from the merger of Ultimate Software & Kronos Inc, we are now UKG.”

Source: RevenueBase Database · checked Sep 14, 2026
8Strong evidenceLittleton, CO, United StatesHQ checked Sep 14, 2026n/a1,376 contacts →

Strong 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 14, 2026
9Partial evidenceWeston, FL, United StatesHQ checked Sep 14, 20265,001-10,0001,084 contacts →

Partial evidence

“Built from the merger of Ultimate Software & Kronos Inc, we are now UKG.”

Source: RevenueBase Database · checked Sep 14, 2026
10Indirect evidenceEl Segundo, CA, United StatesHQ checked Sep 14, 2026501-1,000674 contacts →

Indirect evidence

“For over 25 years, NEOGOV has been at the forefront of public-sector innovation, building technology that helps government and education organizations work smarter, move faster…”

Source: RevenueBase Database · checked Sep 14, 2026
11Indirect evidenceBradenton, FL, United StatesHQ checked Sep 14, 2026201-500586 contacts →

Indirect evidence

“CoAdvantage is now CoAd.”

Source: RevenueBase Database · checked Sep 14, 2026
12Partial evidenceChandler, AZ, United StatesHQ checked Sep 14, 2026201-500436 contacts →

Partial 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 14, 2026
13Indirect evidenceCosta Mesa, CA, United StatesHQ checked Sep 14, 2026501-1,000291 contacts →

Indirect evidence

“Employers need a partner they can rely on to face today’s new challenges.”

Source: RevenueBase Database · checked Sep 14, 2026
14Indirect evidenceBerkeley Heights, NJ, United StatesHQ checked Sep 14, 2026201-500285 contacts →

Indirect evidence

“Viventium provides a SaaS-based payroll and HR solution that is focused on the post-acute care industry, paying over health services employees and supporting clients in all 50…”

Source: RevenueBase Database · checked Sep 14, 2026
15Partial evidenceAustin, TX, United StatesHQ checked Sep 14, 202651-200273 contacts →

Partial evidence

“As the leader in Enterprise Software, our powerful IgniteTech platform helps organizations grow revenue, optimize expense and accelerate transformation through a model where every…”

Source: RevenueBase Database · checked Sep 14, 2026
16Indirect evidenceNashville, TN, United StatesHQ checked Sep 14, 2026201-500271 contacts →

Indirect evidence

“Inova Payroll is a leading employer services company, integrating payroll and human capital management (HCM) technology with personalized support and full-service HR outsourcing.”

Source: RevenueBase Database · checked Sep 14, 2026
17Indirect evidenceHouston, TX, United StatesHQ checked Sep 14, 202651-200224 contacts →

Indirect evidence

“Cybersoft Technologies, Inc.”

Source: RevenueBase Database · checked Sep 14, 2026
18Indirect evidenceLakewood, CO, United StatesHQ checked Sep 14, 202651-200217 contacts →

Indirect evidence

“At Computronix, we value strong relationships with our clients.”

Source: RevenueBase Database · checked Sep 14, 2026
19Indirect evidenceMiami, FL, United StatesHQ checked Sep 14, 2026201-500209 contacts →

Indirect evidence

“HCM Unlocked is ranked as one of America's 100 fastest-growing companies by INC.”

Source: RevenueBase Database · checked Sep 14, 2026
20Indirect evidenceRichmond, VA, United StatesHQ checked Sep 14, 202651-200197 contacts →

Indirect evidence

“Dominion Payroll is a leader in payroll and human resource solutions for clients nationwide.”

Source: RevenueBase Database · checked Sep 14, 2026
21Indirect evidenceShreveport, LA, United StatesHQ checked Sep 14, 2026201-500189 contacts →

Indirect evidence

“At APS, our mission is simple: to make payroll and HR easier.”

Source: RevenueBase Database · checked Sep 14, 2026
22Partial evidenceIndianapolis, IN, United StatesHQ checked Sep 14, 20265,001-10,000160 contacts →

Partial evidence

“Born from the merger of Consona and CDC Software, Aptean, gives businesses of all sizes a competitive edge.”

Source: RevenueBase Database · checked Sep 14, 2026
23Indirect evidenceRochester, NY, United StatesHQ checked Sep 14, 20261,001-5,000159 contacts →

Indirect evidence

“Ovation Payroll is now Heartland Payroll.”

Source: RevenueBase Database · checked Sep 14, 2026
24Partial evidenceMemphis, TN, United StatesHQ checked Sep 14, 202651-200139 contacts →

Partial evidence

“Adams Keegan is a leading national provider of cloud-based, integrated solutions for human resources information systems (HRIS), payroll, employee benefits, and benefits…”

Source: RevenueBase Database · checked Sep 14, 2026
25Strong evidenceFeasterville-trevose, PA, United StatesHQ checked Sep 14, 202651-200128 contacts →

Strong evidence

“Acclaim Systems is certified minority small business (SBA 8(a) & GSA) and is a leading software solution company offering a multitude of comprehensive and customized services…”

Source: RevenueBase Database · checked Sep 14, 2026

Showing 25 of 420 core administrative processing systems software companies based in the United States

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Core administrative processing systems software companies based in the United States at a glance

As of Sep 14, 2026
36.0%Verified-email coverage
328.6Average contacts per company
11-50Median size (employees)
1.9%Largest-city concentration · New York
Sep 14, 2026Page data refreshed

Companies by employee count

1-10
133
11-50
168
51-200
79
201-500
19
501-1,000
4
1,001-5,000
4
5,001-10,000
7
10001+
6

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 420 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 core administrative processing systems software 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 “core administrative processing systems software 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 core administrative processing systems software 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 core administrative processing systems software 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, 49,724 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 14, 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 core administrative processing systems software 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 core administrative processing systems software companies are there based in the United States?

RevenueBase identified 420 core administrative processing systems software 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 core administrative processing systems software companies?

New York leads with 8 headquartered companies, followed by Houston (6) and San Francisco (6).

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 49,724 verified decision-maker contacts tracked across these 420 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 14, 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.