What is third-party assurance?
Third-party assurance is how you demonstrate your security and compliance to the customers, partners, and regulators who vet you as a vendor, by responding to their security questionnaires, RFIs, and audits with accurate answers and real evidence. This guide explains what it is, why it matters, and what it involves.
Definition · Why it matters · What it involves · vs. TPRM
Third-party assurance vs. third-party risk management
These two terms sound alike but point in opposite directions. Third-party assurance is outbound, you prove your own security to the customers vetting you. Third-party risk management (TPRM) is inbound, you assess the security of the vendors who touch your data. If your customers are sending you security questionnaires, you need third-party assurance. If you're the one sending questionnaires to vendors, you need TPRM.
What third-party assurance involves.
In practice, third-party assurance is the ongoing work of answering how your customers vet your security.
Security questionnaires
Responding to standardized and bespoke vendor security questionnaires, like the SIG and CAIQ, that customers send to assess your security before and during a relationship.
RFIs & RFP security sections
Answering the security and compliance questions embedded in requests for information and the security sections of RFPs, where deals are often won or lost.
Customer audits
Supporting direct customer security reviews and audits, where a prospect or client wants a call, a walkthrough, or deeper proof of your controls.
Evidence & documentation
Maintaining a reusable library of policies, certifications (like SOC 2), and audit reports, so every request is answered from a single source of truth.
Why third-party assurance matters.
Security reviews gate deals
Enterprise buyers increasingly won't sign until you clear their security review. Slow or weak answers stall deals; fast, credible ones accelerate them.
Your customers inherit your risk
When a customer trusts you with their data, your security becomes their exposure. Assurance is how you prove you're a safe party to rely on.
Trust is a differentiator
Companies that make assurance easy, with ready evidence and a clear trust story, win business from competitors who treat every questionnaire as a fire drill.
Your evidence, ready to reuse.
Sable keeps your policies, controls, framework mappings, and evidence in one workspace, so every questionnaire and audit response pulls from a single source of truth instead of a last-minute scramble.
- Is data encrypted at rest and in transit?Yes · AES-256 / TLS 1.2+ · evidence linked
- Is MFA enforced for all users?Yes · all users · evidence linked
- Do you have a current SOC 2 Type II?Yes · 2026 report · evidence linked
- Pen test within the last 12 months?Yes · Q1 2026 · evidence linked
- Are sub-processors disclosed?Yes · 14 listed · evidence linked
Need help with third-party assurance?
SubRosa's former auditors respond to your security questionnaires, RFIs, and audits for you. See how our third-party assurance service works.