SOC 2 auditors: how to choose the right audit firm

Yes. SOC 2 is an attestation engagement under the AICPA's standards, and only a licensed CPA firm may issue one. A security consultancy, a compliance platform or a certification body can't.

The people doing the testing often aren't accountants. Good SOC 2 teams are full of former engineers and security specialists. What matters is that a CPA firm supervises the work, stands behind the opinion and is subject to peer review.

Ballpark quotes that one auditor directory collected for buyers in mid-2026 had a median of about $9,000 for a Type 2 at companies under 50 people. A report from a boutique firm is every bit as valid as one from a famous firm. A recognizable name only matters if your buyers are the kind who look for it. Ask one or two of your customers.

1. Check the basics. Confirm the firm's CPA license with its state board and its peer review status with the AICPA.
2. Match the size. A firm that mostly audits banks will apply bank-sized expectations to your 12-person startup.
3. Ask about your stack. They should already understand your cloud provider and, if you use one, your compliance platform.
4. Meet the people. The partner sells and the senior associate tests. Ask who you'll deal with each week.
5. Compare like with like. Same report type, same criteria, same period length, in every quote.

Tick the ones you want and copy them into an email.

CPA firms that do attestation work must enroll in peer review, where another firm inspects their quality roughly every three years. The AICPA runs a public file search where you can look a firm up by name.

It shows whether the firm is enrolled. Full review documents are only public for some firms, so a missing report isn't proof of a problem. A firm that isn't enrolled at all is a reason to stop.

An auditor who promises you'll pass is selling something other than an audit.Your engineer

• A guaranteed result. SOC 2 has no pass or fail. The auditor gives an opinion, and an independent one can't be promised in advance.
• A report in two weeks. One large firm says a proper SOC 2 audit takes at least eight weeks.
• The auditor writes your policies. That breaks independence. They can point at a gap. They can't fill it for you.
• No questions. Real testing produces follow-ups. Silence usually means nobody is reading the evidence.
• A price far below every other quote, with no explanation of how.

A SOC 2 report has five parts: the auditor's opinion, management's assertion, the description of your system, the controls with tests and results, and an optional unaudited section for your own comments.

The opinion comes in four kinds. Unqualified is the clean one. Qualified means clean except for specific issues. Adverse and disclaimer are rare and serious. A few exceptions in testing don't automatically make an opinion qualified. It depends on how many there are and how much they matter.

Earlier than you think. Sign the audit firm before your Type 2 period starts, so the period, the scope and the evidence list are agreed up front. Many audit periods end in December, so firms get busy in the months that follow. Book ahead.