Company lists · Data refreshed September 2026
Top 25 Outsourced administration services based in the United States
RevenueBase identified 1,380 outsourced administration services headquartered in the United States as of September 2026 and tracks 21,195 professional contacts across them, including 4,264 with verified work emails. New York is the largest hub.
This list covers outsourced administration services 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.
The 25 largest outsourced administration services based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 921 contacts → | ||||
Partial evidence “IST Management Services, Inc is an outsourcing company specializing in the life cycle management of your information: From incoming mail, to complex print jobs, to eDiscovery and…” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 2 | 586 contacts → | ||||
Indirect evidence “CoAdvantage is now CoAd.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 3 | 558 contacts → | ||||
Indirect evidence “GSA National has been helping government contractors ensure compliance and streamline costs since 1991.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 4 | 490 contacts → | ||||
Indirect evidence “OBM is a leading business process management company in UAE which provides client driven business management solutions.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 5 | 447 contacts → | ||||
Indirect evidence “Velan Info Services is a leading multidisciplinary service provider with its clients across the globe.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 6 | 297 contacts → | ||||
Indirect evidence “CogNet is a leading Business Process Management (BPM) company supporting our partners in the Human Resource Services industry.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 7 | 293 contacts → | ||||
Partial evidence “Pentegra is a leading provider of retirement plan and fiduciary outsourcing solutions nationwide.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 8 | 220 contacts → | ||||
Partial evidence “Stone Coast Fund Services delivers comprehensive fund administration to alternative investment managers who expect more.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 9 | 201 contacts → | ||||
Strong evidence “Seibels offers the Property and Casualty Insurance industry and Financial Services industry business process outsourcing (BPO) services, and third-party administration (TPA)…” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 10 | 199 contacts → | ||||
Partial evidence “Viteos has been rebranded following the acquisition by Intertrust Group, a world-leader in specialised administration services to clients in over 30 jurisdictions.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 11 | 184 contacts → | ||||
Indirect evidence “Servicios Contables is an Executive Office company located in 115 Parker Rd, Houston, Texas, United States.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 12 | 160 contacts → | ||||
Strong evidence “Countsy provides outsourced Accounting, HR/People Operations, Equity Administration, FP & A, and more for startups, scaleups, and spinouts.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 13 | 149 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 14 | 142 contacts → | ||||
Partial evidence “As a national retirement services company, The Retirement Advantage (TRA) provides third party administration and fiduciary services to plan sponsors, financial advisors, wealth…” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 15 | 142 contacts → | ||||
Partial evidence “Your Remote Assistant is the go-to partner of many investors and startups for administrative manpower because of our high caliber assistants who are smart, experienced, and…” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 16 | 126 contacts → | ||||
Indirect evidence “GLC Business Services provides professional organizations with customer service focused on-site support.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 17 | 123 contacts → | ||||
Partial evidence “Avitus Group is a worldwide company that simplifies, strengthens and grows businesses by providing administrative support (Payroll, accounting, taxes, HR and much more.) When a…” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 18 | 122 contacts → | ||||
Indirect evidence “POMCO is one of the nation’s largest third party administrators offering customized, fully - integrated benefits programs to a broad spectrum of organizations.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 19 | 104 contacts → | ||||
Strong evidence “driasi is a leading provider of outsourced administrative solutions tailored to the insurance industry, and a preferred partner to many of North America's best-known brands.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 20 | 90 contacts → | ||||
Indirect evidence “A company that provides business services.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 21 | 82 contacts → | ||||
Strong evidence “Cobalt MedPlans is an outsourcing partner with core competencies in high end Claims Administration and Contact Center services.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 22 | 81 contacts → | ||||
Indirect evidence “In 2022, as businesses worldwide faced growing pressures, we realized that the biggest challenge wasn’t lack of talent or ideas-it was lack of support.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 23 | 80 contacts → | ||||
Indirect evidence “AdvanStaff HR takes the headache out of HR so busy owners and lean HR teams can focus on running the business, not juggling paperwork.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 24 | 79 contacts → | ||||
Partial evidence “We believe that every business leader should have the opportunity to focus on serving their clients and growing their business, leaving the administrative duties of being an…” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 25 | 78 contacts → | ||||
Partial evidence “HealthNow Administrative Services (HNAS) is a national administrator of custom-designed insured employee benefit programs.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
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: outsourced administration services. 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 outsourced administration services.
- Partial evidence
- Its own public description names part of outsourced administration services, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name outsourced administration services. 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 1,380 outsourced administration services based in the United States
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Outsourced administration services based in the United States at a glance
As of Sep 21, 2026Companies by employee count
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 1,380 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 outsourced administration services, 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 “outsourced administration services”. 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 outsourced administration services), 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 outsourced administration services, 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, 4,264 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.
Outsourced administration services by metro
- Outsourced administration services in New York42
- Outsourced administration services in Houston37
- Outsourced administration services in Atlanta30
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 outsourced administration services, 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 outsourced administration services are there based in the United States?
RevenueBase identified 1,380 outsourced administration services 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?
IST Management, headquartered in Atlanta, tops this list with the largest team on record.
Which city has the most outsourced administration services?
New York leads with 42 headquartered companies, followed by Houston (37) and Atlanta (30).
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 4,264 verified decision-maker contacts tracked across these 1,380 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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Outsourced administration services by geography
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- Outsourced administration services based in Brazil
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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.
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