When New Mountain Capital's Grant Thornton agreed to acquire CBIZ, a nation-wide provider of financial, insurance and advisory services, the headlines wrote themselves: Yet another public accounting firm was being swallowed by private equity money.

Reporters from national news outlets and industry publications all converged on the same question for one of the tax, audit & accounting industry's leading advisors, Allan Koltin, President of Koltin Consulting Group: Is this proof that public ownership of a CPA firm is a bad idea?

"Absolutely not," Koltin says, adding that within three to five years, he expects 8 to 10 publicly traded CPA firms to be acquired with private equity funding. Right now, once CBIZ ceases to exist as a publicly traded company by year-end, Andersen Tax will be the only one left. Koltin argues that the Big Four tax & accoutning firms are simply too large for private equity to absorb, but it's possible all four will eventually go public instead. The Grant Thornton/CBIZ deal, in his view, is a product of unique circumstances.

Inside the private equity consolidation wave

Today there are more than 40 platforms of private equity ownership in accounting firms. Roughly half are what Koltin calls motherships — real operating CPA firms that took outside capital, ranging from heavyweights with revenues over a billion dollars, to middleweights in the $300 million to $1 billion range, down to smaller firms under $300 million. The other half are pure roll-ups, in which a PE-backed platform absorbs smaller firms, lets them keep their name and culture, and quietly builds toward a future sale to another PE group, a family office, a sovereign wealth fund, or a strategic buyer.

Look at the top 30 firms in the country, excluding the Big Four, and Koltin counts roughly 20 out of 26, nearly 80%, that have already done something transformational with a third-party investor: a PE investment, a sale, a deal with a Employee Stock Ownership Plans (ESOP), or a similar deal. Koltin says he expects one or two of the remaining holdouts to follow suit within the next one to two years.

The pattern he's watched repeat over and over again is one in which a hard No becomes a soft no, with soft no meaning a toe in the water. Then, a toe in the water eventually becomes a full transaction.

What clients actually care about

Here's the part that tax, audit & accounting firm leaders tend to get wrong, however. They assume clients are quietly anxious about who owns the firm that's serving them. Koltin's answer is blunt: They aren't.

"I have a problem. Can you service my needs? Can you do it at a fair price? Can you be responsive?" Koltin says those are the questions that clients actually care about.

That's the entire checklist, plus maybe whether there's a personal relationship worth preserving. Questions of ownership structure, who's behind the capital, geography, or whether the work gets done in the domestically or offshore don't register for most decision-makers running a business. Size doesn't matter either, Koltin notes.

That means, the pressure that many firms feel from consolidation is coming from competitors and capital markets, not from client sentiment.

"I have a problem. Can you service my needs? Can you do it at a fair price? Can you be responsive?" Koltin says those are the questions that clients actually care about.

Clearly, accounting isn't the first industry to go through this. Private equity has run this playbook with insurance brokerages and wealth management, consulting, executive recruiting, engineering, and architectural firms for more than two decades — and some of those businesses are already on their fourth or fifth ownership flip.

The tax, audit & accounting industry itself is five years into its version of the cycle, since around August 2021. Law is next: Non-attorney ownership restrictions are starting to loosen, and private equity is already testing the model through managed service organizations that are built around personal injury practices.

If ownership structure becomes a largely settled matter, the more consequential shift will be technology, Koltin explains, adding that the industry is sitting on an hourglass that's half full and half empty at the same time. AI adoption into tax firm work processes is going to compress revenue at pure compliance-driven firms, he argues, as commodity work gets priced down.

However, for firms that wrap real value-added advice around that same technology, it's a margin opportunity, not a threat. Clients won't care how the sausage gets made in the factory, as Koltin puts it, as long as they're getting advice and solutions that are actually worth something.

The data behind the hourglass

The data backs up both sides of that hourglass. Thomson Reuters' Future of Professionals Report 2026 — based on a survey of more than 1,800 professionals across law, tax, audit, and accounting — found that 78% of corporate clients now consider AI-enabled quality improvements very important or essential, yet only 6% say most of their current providers are delivering it.

That gap is exactly the half empty portion of the hourglass that Koltin is describing. Clients aren't indifferent to AI, they're impatient for it, and most professional service firms aren't there yet. The same report puts a number on what that impatience costs — within the next 12 months, 32% of corporate clients say they'll be reconsidering their provider relationships, with one-third of those saying more than $1 million in annual work is on the line. Applied across the legal and CPA markets in the United States, that means roughly $143 billion in client revenue is now in active reconsideration, according to the report.

What firms should be doing now

That's the half full side too, for firms willing to act now. Tax & accounting firm margins averaged around 30% in 2025, some north of 40%, according to the recent Thomson Reuters Institute's 2026 State of Tax Professionals Report — and that's healthy enough to fund real investment. No surprise then that more than half (57%) of professionals surveyed say their firms now name AI their top technology priority, up sharply over the past three years.

In other words, the capital and the client pressure are both already there. What's still being decided, firm by firm, is which firms can convert that pressure into margin and which ones gets priced out of the market as a commodity.

And that is really the critical question that the Grant Thornton/CBIZ deal should raise for firm leaders. Not who owns the firm next door, but whether your own firm lives in the half-full, value-added side of that hourglass, or the half-empty, commoditized one.

You can access the 2026 State of Tax Professionals Report from the Thomson Reuters Institute here