DisclosureIndependent directory. Not a CPA firm. Nothing here is legal, audit, or tax advice. Methodology.

Big Four SOC 2 audit firms: Deloitte, PwC, EY, KPMG

All four Big Four firms (Deloitte, PwC, EY, KPMG) for buyers who specifically need a Big Four name on their SOC 2 — typically pre-IPO companies, PE-backed firms, multinationals, or buyers whose enterprise customers require it. We also list mid-tier alternatives that cover similar engagement scope at a lower entry price.

How we picked: All four Big Four firms (Deloitte, PwC, EY, KPMG) for buyers who specifically need a Big Four name on their SOC 2 — typically pre-IPO companies, PE-backed firms, multinationals, or buyers whose enterprise customers require it. We also list mid-tier alternatives that cover similar engagement scope at a lower entry price.

All Big Four firms in the directory are listed first. Within Big Four, we ordered by confirmed peer review status (all pass) and breadth of services. We then add Grant Thornton, RSM US, and BDO USA as the strongest mid-tier alternatives — all with confirmed peer review pass and overlap in industry served.

Deloitte

Best for: Pre-IPO companies and multinationals where 'Big Four' is a procurement requirement

Pricing: Documented engagement range: $50,000–$150,000

PwC

Best for: Companies wanting Big Four SOC 2 alongside FedRAMP or HITRUST capability

Pricing: Contact for pricing

EY (Ernst & Young)

Best for: Multinational buyers wanting Big Four with strong ISO 27001 capability

Pricing: Contact for pricing

KPMG

Best for: Buyers wanting Big Four with documented short fieldwork timelines

Pricing: Documented engagement range: $40,000–$150,000

Grant Thornton

Best for: Mid-tier alternative when Big Four is overkill but tier-2 national is the right fit

Pricing: Contact for pricing

RSM US

Best for: Mid-market companies wanting national-firm scale at lower entry than Big Four

Pricing: Contact for pricing

BDO USA

Best for: Mid-tier national alternative with confirmed peer review and broad services

Pricing: Contact for pricing

Also considered

Most companies do not actually need Big Four for SOC 2. Mid-tier specialists like Schellman, A-LIGN, and BARR Advisory deliver comparable audit quality at a meaningfully lower price for the typical SaaS buyer. Big Four is best when (a) procurement explicitly requires it, (b) audit work is consolidated with an existing Big Four financial-statement audit, or (c) you are pre-IPO and want continuity through your S-1.