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Big Four vs boutique SOC 2 auditor cost

Cost ranges

ItemRangeNotes
Boutique / specialist CPA (Type II)$15K–$45KSingle-product Security-only scopes with mature evidence ops
Regional / national firm$30K–$80KMid-complexity SaaS with multiple cloud accounts or moderate TSC scope
Big Four global firm$80K–$200K+Brand premium, global coordination, complex entity structures
Hidden delta (same written scope)10–40% spreadSample sizes, remediation support, and report revision assumptions differ

What drives variance

Big Four and boutique CPAs examine the same Trust Services Criteria — the opinion structure is comparable when scope matches. Fee divergence comes from hourly rates, reviewer seniority mix, assumed sample sizes, how aggressively the firm scopes subservice organizations, and whether partners join every walkthrough. Boutiques often move faster on SaaS-native scopes because teams repeat similar cloud architectures weekly; Big Four firms may assign broader teams when procurement mandates the brand. Buyer acceptance matters: if no customer names a firm, a quality boutique report usually satisfies security review. If enterprise MSAs list Deloitte, EY, KPMG, or PwC, factor brand cost as a revenue-unblock line item, not waste. Always compare proposals on identical system boundaries and TSC categories.

Sources & methodology

Frequently Asked Questions

The attestation standard is the same. Strength depends on scope clarity, opinion type, period freshness, and whether exceptions exist — not firm logo alone.

When no buyer requires the brand and budget is constrained. A focused boutique firm with SaaS experience often delivers faster fieldwork at lower cost for Security-only Type II.

When named in enterprise RFPs, when multi-entity global coordination is required, or when board governance expects a familiar firm on the opinion letter.

Yes, but expect a change-of-auditor year with walkthrough overhead and possible scope re-documentation. Many vendors upgrade after Series C or first Fortune 500 logo.

Issue the same system description draft, TSC list, observation window, and entity schedule to each firm. See /costs/soc-2/how-to-choose-auditor for RFP parity checklist.

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Last verified: August 2026 · Primary sources linked above