CAIQ vs SIG: the two vendor questionnaire formats and how to handle each

If you have started receiving security questionnaires from enterprise buyers, you have probably noticed that they are not all the same. Two formats come up again and again, CAIQ and SIG, and knowing which one has landed in your inbox, and why, changes how you should approach answering it. This article explains what each one actually is, how they differ, and how to handle each efficiently, rather than treating every questionnaire as a one off exercise you build from scratch.

What CAIQ actually is

CAIQ stands for the Consensus Assessments Initiative Questionnaire. It is published by the Cloud Security Alliance and is built specifically to assess cloud security, mapping directly to the Cloud Security Alliance's Cloud Controls Matrix. If your product is cloud hosted software, which almost every AI startup is, this is the format built with you specifically in mind.

CAIQ typically runs to somewhere around 250 to 300 questions in its full form, structured mostly as yes or no answers with space for supporting notes, which makes it more mechanical and quicker to work through than a narrative style questionnaire. There is also a shorter CAIQ Lite version, roughly a quarter of the length, covering the same control areas at a higher level, used when a buyer wants a faster initial read rather than full depth. CAIQ is free to access, and many cloud vendors complete it once and publish it publicly on the CSA's STAR registry, so that prospective customers can review it without a bespoke request. If a buyer is tech forward or cloud native themselves, CAIQ is often their format of choice.

What SIG actually is

SIG stands for the Standardized Information Gathering questionnaire, published by Shared Assessments. Where CAIQ is narrowly focused on cloud security, SIG is deliberately broad, covering close to twenty risk domains that go well beyond the cloud, including data privacy, physical security, human resources security, business continuity, and regulatory compliance across many frameworks at once.

SIG comes in more than one form. The full version, sometimes called SIG Core, can run into the many hundreds of questions, occasionally over a thousand depending on how a buyer configures it, and is genuinely substantial. SIG Lite is a condensed version, typically under two hundred questions, used for lower risk vendors or as an initial screen before a fuller assessment. SIG is not free the way CAIQ is, since full access typically requires the requesting organisation to hold a Shared Assessments membership, and it is updated annually to reflect changing regulation. You will most often see SIG from financial services, healthcare, insurance, and other heavily regulated buyers with mature, formal vendor risk programmes.

The practical differences that matter to you

Strip away the detail and here is what actually changes how you respond to each.

• Scope. CAIQ only asks about cloud security. SIG asks about your entire organisation, including things CAIQ never touches, like physical security and HR processes.
• Depth and length. CAIQ, even in its full form, is generally faster to complete because of its structured yes or no format. SIG, especially the full version, demands considerably more narrative detail and time.
• Who sends which. CAIQ tends to come from technology focused buyers assessing you specifically as a cloud vendor. SIG tends to come from larger, more regulated enterprises with a formal third party risk programme covering every kind of vendor, not just cloud providers.
• What receiving one signals. A CAIQ suggests the buyer is specifically testing your cloud posture. A full SIG suggests they have flagged you as a higher risk vendor requiring deep scrutiny. A SIG Lite suggests they currently see you as lower risk, which is good news, but a poor answer can escalate you straight into the full version, so do not treat it casually just because it is shorter.

How to handle each efficiently

The single most important thing to understand is that CAIQ and SIG overlap heavily with each other and with the certifications you may already hold. You do not need to answer either from a blank page every time.

If you already hold a SOC 2 report or ISO 27001 certification, a large share of the heavy lifting for both questionnaires is already done, because the underlying controls they ask about are largely the same ones your audit already covered. The work becomes mapping your existing evidence onto the specific questions asked, rather than building new answers from nothing.

The practical approach that saves the most time going forward is building a security evidence library once, containing your policies, your certifications, your penetration test summary, and clear descriptions of your controls, and then reusing it to populate whichever questionnaire arrives next. Once that library exists, most CAIQ or SIG requests become an afternoon of mapping rather than days of writing from scratch.

For CAIQ specifically, since the format is largely yes or no, be precise and consistent, and where a newer version asks for supporting detail or evidence references, have that ready rather than leaving it blank. Consider preparing a completed CAIQ in advance and being ready to share it proactively, since buyers increasingly appreciate not having to ask.

For SIG, particularly the full version, budget real time for it, because the narrative depth cannot be rushed the way a yes or no format can. If you receive SIG Lite, answer it with the same care as the full version, because a weak or inconsistent answer is what triggers an escalation to the longer form, undoing the time you were trying to save.

The one thing that catches AI startups out on both

Neither CAIQ nor SIG was built with AI products specifically in mind, though both are increasingly adding AI related questions as buyers update their internal processes. Be ready for questions that do not map neatly onto the standard cloud or IT security domains, things like how you handle data sent to AI model providers, whether your AI can be manipulated through prompt injection, or how you prevent one customer's data surfacing in another's results through your model layer. Because these questions may not fit cleanly into the existing structure, a buyer may ask them as an addendum or a free text section rather than a numbered item, so read the whole questionnaire rather than assuming the standard categories cover everything they actually want to know.

The honest takeaway

CAIQ and SIG are not competitors, they are different tools that different kinds of buyers reach for depending on how they think about risk and what kind of vendor you are to them. CAIQ signals a focus on your cloud security specifically. SIG signals a broader, more formal risk review, often from a more regulated buyer. Build a reusable evidence library once, map it into whichever format arrives, and treat every version, however short, with the same care, because a rushed answer on the short form is what turns into weeks of extra work on the long one.