How to Choose a SOC 2 Auditor: 8 Questions to Ask

Why Auditor Choice Matters More Than You Think

Your choice of SOC 2 auditor affects four things: the cost of the engagement, the timeline to report, the quality of the report (and how enterprise security teams receive it), and the practical experience of going through the audit process. A great auditor is a collaborative partner who helps you understand gaps and produce a clean report. A poor auditor is a bottleneck who generates endless PBC requests, moves slowly, and produces reports with unnecessary qualifications.

Enterprise buyers do care about the auditor's name on the report — but less than you might expect. While some procurement teams specifically require a Big Four or top-10 firm, the majority of enterprise security teams care more about whether the report is current, covers the right Trust Service Criteria, and is free of significant exceptions. A clean report from a reputable boutique firm is worth more than a qualified report from a Big Four firm.

Types of SOC 2 Audit Firms

Big Four (Deloitte, PwC, EY, KPMG): fees of $50,000–$150,000+ for Type II. Best for companies whose enterprise customers specifically require a Big Four name, or for companies with complex multi-cloud, multi-product scopes that require deep technical expertise. Slowest to engage — typical lead time is 12–16 weeks.

National firms (BDO, Grant Thornton, RSM, Moss Adams): fees of $30,000–$70,000 for Type II. Good balance of brand recognition and cost. Many have dedicated technology practice groups with strong SOC 2 expertise. Lead time typically 8–12 weeks. These firms handle the majority of mid-market technology company SOC 2 audits.

Technology-focused boutiques (Prescient Assurance, Johanson Group, Sensiba, A-LIGN): fees of $15,000–$40,000 for Type II. Fastest turnaround and best value for early-stage companies. These firms do nothing but tech company SOC 2 audits — their teams know AWS, GitHub, and Okta cold. Trade-off is reduced brand recognition, which matters to some enterprise security teams.

8 Questions to Ask Every Candidate Firm

1. "How many SOC 2 Type II audits did you complete last year for companies using AWS, GitHub, and Okta?" A firm that has done this stack dozens of times will be faster and ask fewer basic questions. 2. "Who will be the engagement partner and engagement manager on my audit?" The partner signs the report; the manager runs day-to-day fieldwork. Meet both before signing — the manager is who you'll actually interact with. 3. "What is your average elapsed time from fieldwork kick-off to draft report?" This tells you how efficient their process is. Under 8 weeks is good; over 12 weeks suggests a backlog or process inefficiency.

4. "How do you handle evidence requests — do you use a client portal?" Auditors who email PBC requests in spreadsheets add administrative friction. Firms with dedicated client portals (or integration with platforms like AuditPath) are faster and easier to work with. 5. "Do you have peer review on schedule and in good standing?" Peer review is the AICPA's quality control mechanism for CPA firms. You can verify peer review status at the AICPA's peer review database. A lapsed or adverse peer review is disqualifying. 6. "What was the qualification rate on your last 20 SOC 2 reports?" Auditors who frequently issue qualified opinions may be overly aggressive in their testing criteria — or may work with clients who are genuinely unprepared. Ask for context on any qualifications.

7. "What is your policy on re-issues or corrections if an error is found after the report is issued?" Errors in SOC 2 reports do happen. Understanding the firm's re-issue process and fee policy before signing prevents uncomfortable surprises. 8. "Can you provide two references — preferably from companies of similar size and stack?" Call those references and ask specifically about fieldwork responsiveness, PBC turnaround time, and whether the final report accurately reflected their security program.

Red Flags to Watch For

Unusually low fees without explanation: if a firm quotes $8,000 for a Type II audit when the market rate is $20,000+, they are either significantly under-scoping the engagement or cutting corners. SOC 2 audits have irreducible time minimums set by AICPA professional standards — below-market pricing means less testing.

Inability to explain their testing methodology: a quality auditor can describe exactly how they will test each criterion — inquiry, observation, inspection, re-performance — and how many samples they will take. Vague answers about "reviewing your documentation" signal a less rigorous approach.

Slow proposal turnaround: if a firm takes more than two weeks to provide a proposal after your initial discovery call, they likely have a backlog that will affect fieldwork responsiveness too. The best firms produce proposals within 5–7 business days.

How to Evaluate Proposals

When comparing proposals, look beyond the total fee to the scope of work described. A $25,000 proposal that includes only Section IV control testing (no system description assistance, no readiness review) may deliver less value than a $32,000 proposal that includes a pre-audit readiness review and system description drafting assistance.

Check that the proposal specifies the observation period dates, the Trust Service Criteria in scope, and the audit standard being applied (SSAE 18, AT-C Section 205). A proposal that is vague on these terms will produce a report that may not meet your customers' requirements.

Ask about what happens if your controls have exceptions. Some firms include one round of management response review in their fee. Others charge hourly for additional procedures. If your first audit has a higher-than-expected exception rate, you don't want to discover this billing structure mid-engagement.

When to Change Auditors

Changing auditors after your first report is common and sometimes beneficial. You might change if: your first firm was too slow or unresponsive; your company has grown to the point where a larger firm's brand recognition matters to enterprise buyers; your first firm had fee increases that make them uncompetitive; or you had significant exceptions in your first report and believe a fresh set of eyes would help.

The cost of changing auditors is primarily time: the new firm must learn your environment, review prior reports, and write a new system description. Budget 4–6 additional weeks for this ramp-up on your first engagement with a new firm. The second year with any firm is faster than the first.

Auditor independence rules prevent your existing auditors from simultaneously providing consulting services on your compliance program. If you want consulting help (beyond audit), it must come from a separate firm. This is why compliance platforms and vCISO consultants (who are not CPA firms) serve a different and complementary role.