Comparison
One access review, two audits, two very different results.
Comparison grids make these two look like rival products. A clearer way in is to take a single control your team already runs, a quarterly review of who can reach production, and watch what happens to it under each. The control barely changes. What changes is the question asked about it, the person asking, and the document your buyer finally holds.
Back to SOC 2 services01 · Under SOC 2
The access review inside a SOC 2 examination
A CPA firm asks whether the review met the relevant criterion, and in a Type 2, whether it ran every time across the period.
- Your control is written into the system description and mapped to the access criteria in CC6.
- In a Type 2, the auditor asks for every review held in the period, commonly selects some, and checks that each was completed, signed off and acted on.
- A missed quarter appears as an exception in the report, next to the test that found it, with your response if you give one.
- The output is a long report with an opinion, the description and the test results, which buyers usually receive under a non-disclosure agreement.
The CPA firm works to the AICPA's attestation rules, AT-C 105 and AT-C 205, and nobody outside a licensed CPA firm may sign the result.
02 · Under ISO 27001
The same review inside an ISO 27001 certification audit
An accredited certification body asks whether the review is part of a working management system that you plan, check and improve.
- The review answers a risk in your risk register and is listed in your Statement of Applicability against Annex A control 5.18, Access rights.
- At the stage 2 audit, the auditor samples evidence of the review and also asks how you know it works: your internal audit, metrics and management review.
- A missed quarter is raised as a nonconformity, minor or major, that you must correct and trace to its root cause within the time the certification body sets.
- The output is a certificate that names your scope and lasts three years, with a short surveillance visit in each of the years after the first.
Certification bodies are accredited to run these audits under ISO/IEC 17021-1 and ISO/IEC 27006. The standard itself is ISO/IEC 27001:2022, with management-system requirements in clauses 4 to 10 and 93 reference controls in Annex A.
03 · What the buyer holds
What ends up in the buyer's hands
The rows below are the questions a vendor reviewer actually asks.
| Reviewer's question | SOC 2 answers with | ISO/IEC 27001 answers with |
|---|---|---|
| Who checked this vendor? | A licensed CPA firm, named on the opinion | An accredited certification body, named on the certificate |
| How much detail can I see? | Controls, tests and any exceptions, control by control | Scope and validity; detail only if the vendor shares its Statement of Applicability or audit reports |
| Does it cover a period of operation? | Yes for Type 2: a stated period, commonly somewhere between three and twelve months | Not as a period; it shows the system was found conforming at the audits |
| Can I check it is genuine? | Ask the CPA firm or read the signed opinion | Check the certification body's records or an accreditation database |
| How current is it? | Look at the period end date; most vendors repeat yearly | Look at the expiry date and the latest surveillance audit |
04 · Extra work each
Work that only one of them asks for
Most security controls serve both. The wrapper around them is where the extra effort sits.
- Only ISO 27001: the management system
- A defined ISMS scope, a documented way of assessing and treating risk, the Statement of Applicability, measurable objectives, a programme of internal audits and a recorded management review.
- Only SOC 2: the description and the period
- A written system description meeting DC 200, evidence for each run of each control across the whole period, and customer duties stated as CUECs.
- Shared: the controls themselves
- Access management, logging and monitoring, change management, supplier reviews, incident handling, backups, awareness training. One evidence store can feed both audits.
05 · Choosing the order
Signals that decide which to do first
Let your open deals decide, then reuse the controls for the second.
- Security questionnaires name oneIf a buyer's form asks for a SOC 2 report or an ISO certificate by name, that request outweighs any general preference.
- Where your buyers sitUS enterprise buyers commonly ask for SOC 2; buyers and public tenders elsewhere commonly name ISO 27001. Treat this as a tendency, not a rule.
- How much detail buyers wantReviewers who want to read control tests lean towards SOC 2. Procurement teams who want a yes or no on certification lean towards ISO.
- Whether you need a governance backboneIf leadership has no regular security review today, building the ISO management system first gives SOC 2 a stronger CC1 to CC5 story later.
Illustrative: an Indian SaaS company selling both ways
A Bengaluru team has two late-stage deals: a US healthcare platform asking for SOC 2 and a German manufacturer whose tender names ISO 27001. It builds one control set, maps each control to both the Trust Services Criteria and Annex A, starts the SOC 2 period, and runs ISO internal audit and management review alongside so the certification audit can follow on the same evidence.
Sources: AICPA Guide, SOC 2 Reporting on an Examination of Controls at a Service Organization; AICPA attestation standards AT-C 105 and AT-C 205; AICPA TSP Section 100 and DC Section 200; ISO/IEC 27001:2022 (clause and Annex A titles); ISO/IEC 17021-1:2015 and ISO/IEC 27006 on certification audits; IAF public guidance on accredited certification.
06 · Go deeper
Go deeper
Dedicated pages on topics this guide only touches.
Choosing between the two
Does an ISO 27001 certificate satisfy a buyer who asked for SOC 2?
Sometimes, if the buyer agrees to accept it.
Some reviewers accept a certificate plus the Statement of Applicability in place of a SOC 2. Others require the SOC 2 report by name. Ask the buyer before assuming either way.
Is there a mapping between the Trust Services Criteria and Annex A?
Yes, the AICPA publishes one.
The AICPA has published a mapping of the Trust Services Criteria to ISO/IEC 27001. Use it as a starting point; your own control matrix should still show which control answers which criterion and which Annex A control.
Can the same firm do both?
Only if it holds both roles, and they remain separate engagements.
A SOC 2 needs a licensed CPA firm; ISO 27001 certification needs an accredited certification body. Some groups have both under one roof, but each audit is still run and signed under its own rules.
Which one costs more effort the first time?
It depends on what you already have.
A team with no risk process or leadership review will find the ISO management system the larger lift. A team with loose evidence habits will feel the SOC 2 period more, since every run of every control must leave a trace.
One set of controls, mapped for both.
In a SOC 2 readiness assessment we map each control to the Trust Services Criteria and to Annex A, so the evidence you collect now can support an ISO 27001 audit later.