Find the right auditor.
42 firms indexed — Big 4 and SME specialists — registered with CPAB (Canada), the PCAOB (US), or both. Filter by segment, country, and tier. Request a quote from any firm and read peer reviews from other issuers.
▸What to look for in an auditor
Required to audit a Canadian reporting issuer (CPAB) or a US public company (PCAOB). Marked on each firm card.
Big 4 for large-cap and multi-entity; SME specialists for TSX-V, CSE, and pre-IPO — often faster and more affordable at comparable depth.
Ask how many similar engagements (industry, size, complexity) the firm has run recently. CPAB inspection findings are public.
CPA Canada Rule 204 limits the non-audit services your auditor can provide. Confirm any advisory or tax work the firm performs doesn't conflict.
Ask for a fee range, scope assumptions, and overrun cost behavior. Serious firms provide a detailed engagement letter and quote.
Ask who the engagement partner and senior manager will be — and for how many consecutive years. Mandatory partner rotation is 7 years for reporting issuers.
Snapshot, not a ranking. This list reflects CPAB and PCAOB registration status as of late 2025. Recent audit engagements per firm are not independently confirmed here — always verify against the most recent issuer filings on SEDAR+ or EDGAR. Auditus.ai does not endorse any firm and does not rank firms against each other.
Send us your firm name, CPAB / PCAOB registration, segments served, and a practice contact. We update the directory by hand during prototype — replies within two business days.
Big 4
8 firmsThe four global networks. Default choice for large-cap, multi-entity, and complex multi-jurisdiction audits. Highest fees and longest fieldwork windows.
SME specialists
34 firmsMid-tier national, regional, and boutique CPAB / PCAOB-registered firms. Built around mid-cap reporting issuers, TSX-V juniors, CSE-listed issuers, and pre-IPO companies. Compete on responsiveness, sector depth, and fee competitiveness.