ISO 27001 vs SOC 2: which one does your customer actually want?

If you sell software to businesses, someone in procurement will eventually ask for one of these, and often both. They are frequently described as equivalent. They are not, and choosing the wrong one wastes months.

What each one is

ISO/IEC 27001 is an international standard for an information security management system. Certification means an accredited certification body has audited your ISMS and confirmed it conforms to the standard. You receive a certificate, valid for three years, with annual surveillance audits.

SOC 2 is an attestation framework from the American Institute of Certified Public Accountants. A licensed CPA firm examines your controls against the Trust Services Criteria and issues a report describing them and, for a Type 2 report, testing whether they operated over a period, typically six to twelve months. You receive a report, not a certificate, and it is normally shared under NDA.

The key differences

	ISO 27001	SOC 2
Type of output	Certificate, publicly verifiable	Report, shared under NDA
Who issues it	Accredited certification body	Licensed CPA firm
Basis	International standard with 93 defined Annex A controls	Trust Services Criteria; controls are defined by you
Validity	Three years with annual surveillance	Covers a reporting period; renewed annually
Focus	The management system: risk-based, continually improved	The controls: designed and operating effectively over the period
Recognition	Global, strongest outside North America	Strongest in the United States
Scope flexibility	Defined scope statement on the certificate	Defined system description in the report

Who asks for which

• US enterprise customers, especially in tech, tend to ask for SOC 2 Type 2 first. Their vendor risk programs are built around it.
• European, UK, Asia-Pacific, and public-sector customers tend to ask for ISO 27001. Tenders almost always specify it.
• Regulated industries such as financial services and healthcare often accept either as evidence of governance, and may ask for both from strategic suppliers.
• Large multinationals frequently accept ISO 27001 globally and SOC 2 for their US operations.

The most reliable way to decide is to ask your three largest prospects what they require. It is cheaper than guessing.

How they overlap

Substantially. A well-built ISMS generates most of the evidence a SOC 2 auditor needs, and the Trust Services Criteria map closely to ISO 27001 Annex A. Compliance automation platforms exist precisely because the underlying controls are largely shared: access control, change management, vulnerability management, logging, vendor management, incident response, and business continuity.

The management system parts of ISO 27001 are the main difference. SOC 2 does not require a risk assessment methodology, a Statement of Applicability, internal audits, or management reviews in the way ISO 27001 does. Organizations that do ISO 27001 first usually find SOC 2 straightforward; the reverse involves adding governance structure.

Doing both

If you need both, sequencing matters:

1. ISO 27001 first if your market is international or you want a framework that will still be useful in five years. The ISMS gives you a governance backbone; SOC 2 then becomes an additional attestation over the same controls.
2. SOC 2 first if a US customer is holding a contract and can wait the observation period but not longer. Plan the controls with ISO 27001 in mind so you are not rebuilding later.

Audit periods can be aligned so surveillance audits and SOC 2 observation windows share evidence. Tell both auditors about the other engagement.

Common misconceptions

• “SOC 2 is a certification.” It is not. There is no certificate, no registry, and no accreditation body. The report is the deliverable.
• “ISO 27001 is just paperwork.” A poorly run ISMS can be. A properly audited one tests whether controls are effective, in the same way SOC 2 does.
• “One replaces the other.” Sometimes, if your customers agree. Ask them.
• “ISO 27001 has a public list of controls so it is easier.” The Annex A controls are a starting point. Which ones apply, and how, is determined by your risk assessment, and the auditor tests your reasoning.

Our view

For companies with international customers or public sector ambitions, ISO 27001 is the more durable investment. For US-focused SaaS companies selling to other technology companies, SOC 2 opens more doors faster. If you have the resources and the customer demand, doing both from one set of controls is efficient and increasingly normal.

• SOC 2
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