By revenue, the top accounting firms in the US are the same four names at the top of the national revenue lists: Deloitte, PwC, EY and KPMG. What those four mean for a firm that is buying audit capacity is a separate question. Even among those four the lists disagree, and one well-known ranking puts PwC ahead of Deloitte while another puts Deloitte ahead of PwC. Neither is wrong. Each publisher scores a different input, and the input decides the order.
What Are the Top 10 Accounting Firms in the US?
By US net revenue on the 2026 IPA 500, the order is Deloitte, PwC, EY, KPMG, RSM US, Baker Tilly, BDO USA, CBIZ, Grant Thornton and Forvis Mazars. IPA notes that positions shift each year with organic growth, mergers and acquisitions, and changing market conditions, so the order below the Big Four is the part most likely to change.
Deloitte is the largest of the Big Four on that measure. It reports $35,687,000,000 on the 2026 IPA 500, ahead of PwC at $25,574,000,000.
Who Publishes the Top Accounting Firms Rankings, and What Each Scores
Each list below scores something different, so a firm can sit high on one and be absent from another without anything being wrong.
INSIDE Public Accounting Ranks Net Revenue
The IPA 500 ranks firms by net revenue using self-reported data submitted through the IPA Practice Management Survey, publishes every August, and splits the field into IPA 100, 200, 300, 400 and 500 groupings. It runs from Deloitte at the top to a firm reporting $6,124,123 at No. 500.
Both halves of that method matter. The metric is revenue, so the list answers a size question and only a size question. The data is self-reported through a survey, so a firm that never completes the survey never appears, whatever its size.
Accounting Today Ranks Revenue Nationally and by Region
The Top 100 Firms and Regional Leaders lists rank the top firms by revenue, both nationwide and in specific regions of the country, and they publish in March.
Inclusion is opt-in there too. Firms that believe they should be considered and have not been contacted are told to email the editor and ask. The result is a ranking of the firms that answered, not of the firms that exist.
Vault Ranks Prestige, Scored by Other Firms' Staff
Vault's 2027 Most Prestigious Accounting Firms ranking puts the same four at the top in a different order. PwC leads at 8.938, Deloitte follows at 8.869, EY at 8.692 and KPMG at 8.393, while Grant Thornton, in fifth, scores 7.047.
The method explains both the reordering and that gap. Participants rate companies other than their own on a scale of 1 to 10, are asked to rate only firms they are familiar with, and are not permitted to rate their own or a former employer. Vault averages those prestige scores and ranks them in order.
Notice where the break falls. It sits between the fourth and fifth firms on this reputation measure, and the revenue measure breaks in the same place. That is worth noticing, though prestige and revenue are not independent of each other.
Construction Executive Ranks One Niche on Six Weighted Inputs
Construction Executive's Top 50 Construction Accounting Firms ranking was built by asking more than 700 US construction accounting firms to complete a survey. The survey collected construction-practice revenue, the number of CPAs in that practice, the share of total firm revenue coming from construction, the number of states the firm is licensed in, the year the construction practice was established, and the number of AEC clients served, meaning clients in architecture, engineering and construction. An algorithm then weighted those factors in descending order of importance.
That is the most transparent method of the four and also the narrowest. It answers one question well, which is who runs the largest and most construction-focused practice, and it says nothing about a firm outside that niche.
What a Rank Tells You, and What It Does Not
A place on a revenue list is a size measurement, and the publisher claims nothing more than that.
The distances involved are worth seeing. On the 2026 IPA 500, KPMG holds No. 4 with $15,900,000,000 in net revenue and the fifth-placed firm, RSM US, reports $4,199,405,000. That gap is larger than the entire revenue of any single firm below the Big Four. Lower down, the field compresses hard, with No. 100 reporting $67,736,406, No. 200 reporting $26,706,397 and No. 300 reporting $16,602,065.
So a rank is a revenue position relative to the firms that answered, and it moves when their revenue moves as well as when yours does. That is useful as a benchmark and useless as a verdict on quality, on how the work gets staffed, or on whether the firm has room to take on more of it.
Ownership is also changing near the top of these lists. Private equity investment in accounting firms changes what sits behind a revenue number, and it is a subject of its own.
The Public Records That Carry Checkable Facts
A ranking is a publisher's measurement. A register is a record kept by a regulator or a standards body, and three of them hold facts about US accounting firms that no list scores.
PCAOB Registration and the Form 2 Annual Report
A firm that issues audit reports for issuers, brokers or dealers, or plays a substantial role in one, has to be registered with the Public Company Accounting Oversight Board, and the Board's rules put a recurring filing behind that registration. Rule 2201 requires a registered firm to file an annual report on Form 2 no later than June 30 of each year, unless the Board approved its registration in the period from April 1 to June 30 that year. Rule 2300 then makes a registration application public as soon as practicable after the Board approves or disapproves it, and the other forms filed under those parts of the rules public as soon as practicable after filing, subject to the confidential treatment a firm may request for proprietary or legally protected information.
That makes the register a running record rather than a snapshot. A firm summary page shows that firm's registration, its annual and special report filings, its inspection reports and any disciplinary actions, which is four kinds of primary record about one firm.
Most US firms are not there, because most do not audit public companies. Read absence as scope rather than as a grade, and read presence as a public file that no rank contains.
AICPA Peer Review Carries a Grade
The AICPA peer review program examines the design and operating effectiveness of a firm's quality management system every three years, and the AICPA describes it as covering virtually every firm that performs accounting or auditing work. Firms receive one of three grades, Pass, Pass with Deficiencies or Fail.
The Peer Review Public File lists public accounting firms and their enrollment status, and shows whether a firm belongs to the Private Companies Practice Section, the Employee Benefit Plan Audit Quality Center or the Governmental Audit Quality Center. The latest accepted peer review documents are viewable for firms in those sections and for firms that have asked to make theirs public.
A peer review grade is a judgment on how a firm does its work, reached by another firm under published standards. None of the rankings score it.
The State Board License Lookup
State boards of accountancy feed their license data to CPAverify, and with 53 jurisdictions participating NASBA describes it as the only official, free, single-source national database of licensed CPAs available to the public.
Look your own firm up in it once, the way a prospect or a peer reviewer would, and read what the board record says rather than what your website says. The same check, run against a credential somebody else has claimed, has a longer form in verifying an offshore CPA's license.
Where a Rank Stops Being Useful to a Firm Owner
If you run a firm, a ranking answers one question, which is how the largest firms that answered a survey compare on size. The 2026 IPA 500 stops at $6,124,123 in net revenue at No. 500, so for most firms it answers nothing at all, and even for a firm on the list it settles nothing else.
What settles something is your capacity model. Who can review the work, how many hours sit behind each deadline, and what happens in March when both run short are the questions a rank never touches. Capacity planning and the firm metrics worth tracking work on them directly.
Say two firms sit a few places apart on a revenue list. One runs three reviewers and a clean queue. The other runs one reviewer, a backlog behind that reviewer, and partners who stop selling in February because nobody can absorb the work. The list cannot see the difference, and neither can anyone reading it.
Capacity Is the Number Behind the Rank
A firm's rank moves when its net revenue moves relative to the firms that answered the survey, and one of the few levers under a partner's own control is finally taking the work the firm has been turning away. That makes the ranking question and the capacity question the same question, asked a year apart.
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