Big Four or Boutique for Audit Readiness: What You Are Paying For

There is no published, verifiable number for how much less a boutique charges than a Big Four firm for audit readiness work, and the figure you will be quoted does not mean what it appears to mean. The usual citation is Grant Thornton's article on internal audit co-sourcing, and the sentence it actually contains reads: "In the last few years, the cost of maintaining professional wages for anyone within the internal audit function has increased between 20 percent and 40 percent." That is wage inflation for in-house audit staff. It is not a discount anybody offers against a Big Four proposal. We are a boutique, the misreading flatters us, and we are not going to publish it.

What you can verify sits in the two proposals on your desk: who does the work, at what seniority, and how many hours are review rather than doing. This piece works that comparison, names the three cases where the Big Four premium is the correct purchase, and ends with the situations where you should not hire a boutique either.

Key takeaways

• The "20 to 40 percent cheaper" figure in circulation traces to a sentence about in-house wage inflation, not to any comparison between firm types. Do not budget from it.
• The real difference between the two proposals is the staffing pyramid. A large-firm engagement layers partner, manager, and rotating-associate hours; a boutique engagement is usually one senior practitioner doing the work directly.
• The premium buys three specific things: a brand a board or acquirer has already accepted, multinational delivery capacity, and a bench that absorbs parallel workstreams. If none of those applies to you, firm size is the wrong selection criterion.
• Neither firm type escapes the independence constraint. Whoever designs and implements your controls cannot also issue your SOC 2 opinion, so both proposals are for readiness work only.
• Compare proposals on named deliverables and named people, never on the total. Two documents both titled "SOC 2 readiness" routinely describe different amounts of work.

The number everyone quotes, and what its source actually says

Search for the cost difference and the same claim comes back from consultancy blogs, aggregator pages and assistant answers: co-sourced or outsourced arrangements cost 20 to 40 percent less than a fully staffed function, attributed to Grant Thornton and Baker Tilly.

We read the Grant Thornton page on 2026-08-22. It contains exactly one 20-to-40-percent sentence, quoted in full at the top of this article, and its subject is the rising cost of professional wages inside internal audit functions. The page argues that wage pressure is one reason co-sourcing looks attractive. It does not quantify a saving. The Baker Tilly page normally cited alongside it returned an HTTP 403 and could not be read at all.

So the number has drifted from "your in-house salaries went up by this much" to "a boutique is this much cheaper than the Big Four". Those are different claims about different things, and the second has no source we can find.

Two consequences follow, and the second matters more. Do not put a percentage into a budget model on this basis. Then use it as a filter: if a firm's proposal leads with that figure, ask them for the sentence it comes from, because how they answer tells you how the rest of their work will be sourced.

The wage statistic is still useful, pointed at a different question. It is evidence that the in-house option is getting more expensive, which is a real input into the build-versus-buy decision covered in our piece on hiring a compliance manager versus outsourcing. It says nothing about which outside firm to pick.

What you are really comparing: the staffing pyramid

Strip the logos off and the structural difference between the two proposals is who is billed against your hours.

A large-firm engagement is built as a pyramid, and it has to be, because that is how a firm with tens of thousands of practitioners delivers consistent work. A partner owns the relationship and signs things. A manager runs the engagement and reviews. Associates do most of the fieldwork, and they rotate, often annually, because rotation is how a large firm develops people. Your hours are distributed across that stack, and the blended rate on your invoice is its weighted average.

A boutique engagement is usually flat. One senior practitioner scopes the work, does the work, sits in the meetings, and is still there next year. There is no review layer because the reviewer and the doer are the same person, which is at once the model's biggest advantage and its biggest exposure.

Neither shape is better in the abstract. The pyramid gives you redundancy, a documented methodology, quality review by someone other than the author, and the ability to put six people on six workstreams next Monday. The flat model gives you senior judgment on the actual work rather than on the review of it, and continuity of context that a rotation schedule cannot produce.

What the pyramid does mean is that the seniority of the person answering your questions in the sales process is a poor predictor of the seniority of the person doing your work. That is not a criticism, it is the model. It does mean "who specifically will be in our walkthroughs" belongs in both conversations, and the answers will be structurally different.

Three cases where the Big Four premium is the right purchase

Against our own interest, because these are engagements we would lose.

Someone with veto power has already named the tier. An acquirer's diligence checklist, an underwriter, an audit committee, or a customer contract that specifies a firm tier in writing. When the requirement is written down, arguing that the deliverable would be identical is arguing about the wrong thing. Buy the brand, because the brand is the requirement. Note the shape of the test: a written requirement from a party who can stop your transaction, not a general sense that a bigger name looks better. Our piece on whether your SOC 2 auditor's brand matters works the same distinction from the audit side.

Multinational scope with real jurisdictional spread. Several legal entities, several regulators, data residency questions in more than one region, local-language documentation. Coordinating three regional specialists yourself is a project management job you did not ask for, and a global delivery network genuinely solves it. Here the premium is a coordination fee, and coordination is worth paying for when there is enough of it.

Parallel workstreams against a fixed external date. An IPO timeline, a regulatory deadline, or a diligence window where readiness, SOX scoping, privacy, and a remediation programme all move at once. A single senior practitioner cannot be in four places, and a firm with a bench can. The arithmetic is not about quality, it is about headcount against a calendar.

If none of those three describes you, the premium buys something you will not use.

What a boutique genuinely cannot give you

Four things, stated plainly, because a comparison that only lists the other side's weaknesses is marketing.

Redundancy. If your practitioner is unavailable during fieldwork week, a large firm reassigns and a boutique reschedules. Ask what happens in that scenario, and treat a vague answer as the answer.

Surge capacity. Adding a second framework mid-engagement is a staffing question a boutique answers with a calendar and a large firm answers with people.

Independent quality review. In the pyramid, someone who did not write the work product reviews it. In the flat model that review either does not happen or is a peer favour. Some boutiques buy it back with a formal second-reader step; ask whether yours does.

A name that ends an argument. If your CFO has to defend the choice of advisor to a board that knows neither firm, the household name does work a good deliverable cannot.

How to compare two proposals that are not comparable

The proposals will not have the same shape, and comparing totals is how buyers get surprised. Restate both against these five questions before you look at either number.

• Named people and their hours. Not "a dedicated team". Names, seniority, and the split of hours between doing and reviewing. Accept "we staff at signature" only alongside a written seniority floor.
• The deliverable list, itemised. Scope recommendation, gap list, remediation plan, evidence rehearsal, system description drafting, walkthrough attendance. Two "readiness" proposals frequently differ on three of those six. Our readiness assessment guide is a fair checklist to hold both against.
• Who is in the room during fieldwork. Attending walkthroughs and answering follow-ups is a large share of the value, and it is frequently unpriced. Ask whether it is included or a change order.
• What happens when scope moves. It will. Get the change mechanism in writing; firms differ far more here than in the headline fee.
• Who owns the system description. It is human-authored, it is a common source of revision cycles, and a proposal silent on it has quietly left it with you.

Price the two documents only after both describe the same work. For the cost structure of the audit itself rather than the readiness work, our SOC 2 cost breakdown publishes the site's reconciled figures with their sources, and it is the page to cite rather than any number in this one.

The independence rule constrains both of them

This catches buyers of both firm types, and it is not negotiable.

A SOC 2 report is an attestation issued by a licensed CPA firm. Linford & Company, a CPA firm that sells SOC audits and so has an interest in the answer, states the rule bluntly: a firm that is not a certified CPA firm cannot complete a SOC 1 or SOC 2 audit acceptable in the eyes of the AICPA, and a report not completed by a CPA firm should not be relied on. AICPA independence requirements then stop that CPA firm from attesting to controls it designed and implemented.

Large firms with separated advisory and attestation practices can sometimes hold both relationships with real safeguards and real distance. A single small firm offering to build your controls and issue your opinion cannot. Either way, the readiness proposal in front of you is for readiness work only, and any firm implying otherwise has told you something important about itself.

When you should not hire a boutique, including us

Three situations, and in each of them we would tell you so.

The tier is already written down. The cleanest of the three. If an acquirer's checklist names a firm tier, hiring us is buying an argument you lose later, at a worse moment.

Your scope is genuinely simple and you have an owner. One product, one cloud account, the Security category only, and someone internal whose job actually includes this. Buy a compliance platform, have a scoping conversation with your examiner, and spend the consulting budget on remediation. We make the same argument at length in our platform-versus-consultant piece.

You need six things done in parallel by a fixed date. One senior practitioner against four simultaneous workstreams is arithmetic, not effort. Buy the bench.

Where Top Floor fits

We are the flat model, and this article describes our own trade-offs as well as the category's. What we sell is audit and assurance management: scoping, readiness work, evidence coordination, and sitting next to you through fieldwork and findings. What we never sell is the opinion, because we do not issue attestations and cannot, which is precisely why we can tell you to buy the other thing.

When the real problem is that nobody owns the compliance calendar between audits, the purchase is compliance as a service rather than a project; when nobody senior owns security decisions at all, it is vCISO. Our positioning piece states the model without the comparison framing.

How to decide this week

Ask the deciding stakeholder directly, in writing, before you compare anything: "Is there a firm tier this engagement has to come from?" A board member, an acquirer's diligence lead, or a customer's vendor risk team will answer in a sentence, and that sentence settles most of the decision. Do not infer it, because inferring it is how companies buy a premium nobody asked for.

Then restate both proposals against the five questions above until they describe the same work. If they still disagree on deliverables after one round of clarification, that disagreement is the finding, and it predicts how the engagement will run.

Finally, ignore any percentage either firm quotes you about the other. As of August 2026 there is no published comparison of readiness fees by firm type that we can verify, and the figure most often cited is about something else entirely.

Frequently asked questions

Are boutique firms cheaper than the Big Four for audit readiness?

Usually yes on the invoice, but there is no published, verifiable figure for how much, and you should be suspicious of anyone who quotes one. The structural reason a boutique bills less is the staffing pyramid: a large-firm engagement distributes your hours across partner, manager and rotating associate rates plus firm overhead, while a boutique engagement is typically one senior practitioner doing the work directly. That is a real difference you can confirm by asking both firms to name the people and their hours. Anything beyond that, including the 20-to-40-percent figure in wide circulation, is not something we can source.

Where does the 20 to 40 percent savings figure come from?

From a misreading. The Grant Thornton article on internal audit co-sourcing that everyone cites contains one 20-to-40-percent sentence, and its subject is that the cost of maintaining professional wages inside internal audit functions rose by that much in recent years. That is in-house wage inflation, not a discount a co-sourced or boutique provider offers against a large firm. The claim mutated in retelling, and the Baker Tilly page usually cited alongside it was not reachable when we checked on 2026-08-22. Use the wage figure for what it actually supports, which is that staffing the function internally is getting more expensive.

Can one firm do both our readiness work and our SOC 2 audit?

Not a single small firm, no. A SOC 2 report is an attestation issued by a licensed CPA firm, and AICPA independence requirements prevent that firm from attesting to controls it designed or implemented. Large firms with genuinely separated advisory and attestation practices can sometimes hold both relationships with documented safeguards, which is one thing the premium buys. For everyone else the working structure is one party for preparation and a different, independent party for the examination, and a firm offering you both in one package has described an independence problem rather than a convenience.

What should we ask a boutique that we would not ask a Big Four firm?

Three things the flat model creates. First, what happens if your named practitioner is unavailable during fieldwork week, and get a real answer rather than reassurance. Second, whether anyone other than the author reviews the work product, since the independent quality review that is structural in a large firm is optional in a small one. Third, what the firm's capacity looks like in your specific delivery window, because a boutique's constraint is calendar rather than headcount. Ask a large firm the mirror-image questions: who actually does the fieldwork, at what seniority, and whether that person rotates off next year.