Company lists · Data refreshed September 2026

Top 25 Tax processing outsourcing companies based in the United States

Name: Tax processing 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 29, 2026 3,818 companies tracked

RevenueBase identified 3,818 tax processing outsourcing companies headquartered in the United States as of September 2026 and tracks 89,077 professional contacts across them, including 15,642 with verified work emails. New York is the largest hub.

This list covers tax processing 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 29, 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 29, 2026 86% judged on-target in blind review

3,818Companies

89,077Contacts tracked

15,642Verified emails

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The 25 largest tax processing outsourcing companies based in the United States

Ranked by team size

Top 25 of 3,818 tax processing outsourcing companies based in the United States, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to tax processing 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	H&r Block	Indirect evidence	Kansas City, MO, United StatesHQ checked Sep 29, 2026	10001+	59,451 contacts →
	Indirect evidence “H&R Block’s purpose is simple: To provide help and inspire confidence in our clients and communities everywhere.” Source: RevenueBase Database · checked Sep 29, 2026
2	RYAN	Partial evidence	Dallas, TX, United StatesHQ checked Sep 29, 2026	5,001-10,000	6,089 contacts →
	Partial evidence “Ryan, an award-winning global tax services and software provider, is the largest Firm in the world dedicated exclusively to business taxes.” Source: RevenueBase Database · checked Sep 29, 2026
3	Drake Software	Partial evidence	Franklin, United StatesHQ checked Sep 29, 2026	501-1,000	561 contacts →
	Partial evidence “Drake Software, a private company founded in 1977, provides software solutions to over tax and accounting firms that file more than 40 million tax returns every year.” Source: RevenueBase Database · checked Sep 29, 2026
4	Cohesive	Indirect evidence	Exton, PA, United StatesHQ checked Sep 29, 2026	501-1,000	364 contacts →
	Indirect evidence “Cohesive is a leading solutions provider and systems integrator for IBM Maximo.” Source: RevenueBase Database · checked Sep 29, 2026
5	Advantage ONE TAX Consulting	Partial evidence	Sterling, VA, United StatesHQ checked Sep 29, 2026	201-500	347 contacts →
	Partial evidence “Advantage One Tax Consulting is a multi-disciplinary group of highly experienced tax professionals who understand the tax practice in its true spirit, examine the issues it faces…” Source: RevenueBase Database · checked Sep 29, 2026
6	Unison Globus	Partial evidence	Coral Springs, FL, United StatesHQ checked Sep 29, 2026	201-500	320 contacts →
	Partial evidence “Unison Globus is a global accounting outsourcing and offshore staffing partner dedicated to supporting CPA firms and accounting professionals.” Source: RevenueBase Database · checked Sep 29, 2026
7	Mayatax	Indirect evidence	Houston, TX, United StatesHQ checked Sep 29, 2026	501-1,000	269 contacts →
	Indirect evidence “Growth exposes financial weakness.” Source: RevenueBase Database · checked Sep 29, 2026
8	Synergi	Strong evidence	Florence, SC, United StatesHQ checked Sep 29, 2026	201-500	214 contacts →
	Strong evidence “Synergi specializes in processing federal and state tax credits for employers across the United States and Puerto Rico.” Source: RevenueBase Database · checked Sep 29, 2026
9	Zenwork, INC	Partial evidence	Fayetteville, AR, United StatesHQ checked Sep 29, 2026	51-200	206 contacts →
	Partial evidence “Zenwork, through its Tax1099 and Compliancely brands, is a fast-growing digital tax compliance and regulatory reporting technology company, with 10+ years of experience powering…” Source: RevenueBase Database · checked Sep 29, 2026
10	Infinity Globus, A Springline Company	Partial evidence	Dallas, TX, United StatesHQ checked Sep 29, 2026	201-500	168 contacts →
	Partial evidence “Infinity Globus, a Springline company, is a leading accounting outsourcing firm with over two decades of industry experience, providing tailored taxation and accounting services…” Source: RevenueBase Database · checked Sep 29, 2026
11	Konnect Books & Taxes- Virtual CFO & USA TAX Consultants	Partial evidence	New York, NY, United StatesHQ checked Sep 29, 2026	51-200	145 contacts →
	Partial evidence “Konnect Books & Taxes, is an International Bookkeeping, Tax & Advisory firm, in the USA, with CPAs & Accountants, ready to help you take care of ALL your numbers.” Source: RevenueBase Database · checked Sep 29, 2026
12	Instead	Partial evidence	San Francisco, CA, United StatesHQ checked Sep 29, 2026	51-200	140 contacts →
	Partial evidence “Instead is where tax work gets done.” Source: RevenueBase Database · checked Sep 29, 2026
13	Corporate Payroll Services	Partial evidence	Peachtree Corners, GA, United StatesHQ checked Sep 29, 2026	51-200	126 contacts →
	Partial evidence “At Corporate Payroll Services, we relieve you of the burden of processing payroll.” Source: RevenueBase Database · checked Sep 29, 2026
14	Mytaxfiler	Partial evidence	Plano, TX, United StatesHQ checked Sep 29, 2026	51-200	100 contacts →
	Partial evidence “At MyTaxFiler, we offer more than just tax preparation-we provide peace of mind.” Source: RevenueBase Database · checked Sep 29, 2026
15	Archer Lewis	Partial evidence	Chicago, IL, United StatesHQ checked Sep 29, 2026	501-1,000	94 contacts →
	Partial evidence “Archer Lewis is your local trusted advisor for accounting and tax services.” Source: RevenueBase Database · checked Sep 29, 2026
16	APRIL	Partial evidence	New York, NY, United StatesHQ checked Sep 29, 2026	51-200	79 contacts →
	Partial evidence “april partners with wealth management firms, banks, and SMB platforms to embed tax filing, planning, and insights directly into the financial platforms people use every day to…” Source: RevenueBase Database · checked Sep 29, 2026
17	R&g Brenner TAX Accounting	Partial evidence	Valley Stream, NY, United StatesHQ checked Sep 29, 2026	51-200	78 contacts →
	Partial evidence “Tax Consulting Services Individual Tax Return Preparation * Electronic Filing * Refund Anticipation Loans * Same Day Refund Anticipation Loans * Refund Anticipation Checks * State…” Source: RevenueBase Database · checked Sep 29, 2026
18	Colbert Ball TAX Service	Partial evidence	Houston, TX, United StatesHQ checked Sep 29, 2026	11-50	77 contacts →
	Partial evidence “Colbert/Ball Tax Service understands that whenever a customer visits their location for service, the client will be immediately assisted by a trained professional.” Source: RevenueBase Database · checked Sep 29, 2026
19	XIT Solutions INC	Indirect evidence	Oakbrook Terrace, IL, United StatesHQ checked Sep 29, 2026	51-200	74 contacts →
	Indirect evidence “XIT Solutions Inc, is a decade old startup with presence in US, Canada & India.” Source: RevenueBase Database · checked Sep 29, 2026
20	Intellgus	Partial evidence	Texas, TX, United StatesHQ checked Sep 29, 2026	51-200	59 contacts →
	Partial evidence “Welcome to Intellgus, the firm that’s reshaping the landscape of offshore staffing solutions for CPAs, accounting firms, and tax professionals.” Source: RevenueBase Database · checked Sep 29, 2026
21	Arvo Tech	Partial evidence	Columbus, OH, United StatesHQ checked Sep 29, 2026	11-50	56 contacts →
	Partial evidence “Founded by tax experts and backed by proprietary technology, Arvo is the only holistic approach that brings together the ability to develop and document a tax strategy with tax…” Source: RevenueBase Database · checked Sep 29, 2026
22	Anybill Financial Services	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	11-50	55 contacts →
	Partial evidence “Anybill is the leading provider of tax payment services, focusing exclusively on automating tax payments for our clients and partners.” Source: RevenueBase Database · checked Sep 29, 2026
23	Think LLP	Partial evidence	Washington, DC, United StatesHQ checked Sep 29, 2026	51-200	54 contacts →
	Partial evidence “Think, LLP is a national professional tax services firm that consists of former Big-4 partners from the national tax practices, attorneys, CPAs, engineers, former IRS technicians…” Source: RevenueBase Database · checked Sep 29, 2026
24	The Accounting Guys	Indirect evidence	Provo, UT, United StatesHQ checked Sep 29, 2026	51-200	54 contacts →
	Indirect evidence “At The Accounting Guys, we help our clients, located throughout the US and Canada, make intelligent business decisions-right from the get-go!” Source: RevenueBase Database · checked Sep 29, 2026
25	The Accounting LAB	Partial evidence	Knoxville, TN, United StatesHQ checked Sep 29, 2026	51-200	48 contacts →
	Partial evidence “At The Accounting Lab, we are dedicated to helping individuals and businesses optimize their financial success through effective tax minimization strategies.” Source: RevenueBase Database · checked Sep 29, 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: tax processing 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 tax processing outsourcing companies.
Partial evidence: Its own public description names part of tax processing outsourcing companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name tax processing 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 3,818 tax processing outsourcing companies based in the United States

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Tax processing outsourcing companies based in the United States at a glance

As of Sep 29, 2026

17.6%Verified-email coverage

23.3Average contacts per company

1-10Median size (employees)

2.5%Largest-city concentration · New York

Sep 29, 2026Page data refreshed

Companies by employee count

1-10

2,945

11-50

660

51-200

133

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

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 3,818 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 tax processing 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 “tax processing 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 tax processing 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 tax processing 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, 15,642 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 29, 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.

Tax processing 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 tax processing 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 tax processing outsourcing companies are there based in the United States?

RevenueBase identified 3,818 tax processing 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?

H&r Block, headquartered in Kansas City, tops this list with the largest team on record.

Which city has the most tax processing outsourcing companies?

New York leads with 97 headquartered companies, followed by Houston (95) and Miami (52).

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 15,642 verified decision-maker contacts tracked across these 3,818 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 29, 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.