SOC 1 Bridge Letters: Keeping Stakeholder Confidence Intact

If you’ve completed a SOC 1 (System and Organization Controls 1) audit, you know that tasks like testing and documenting controls don’t end with the final report. Often, there’s a gap between your audit period and your client’s year-end. 

This is where a bridge letter comes in. It’s a simple way of saying, “Nothing major changed since our last audit” without going through another round of testing.

In this article, we will explain what a SOC 1 bridge letter is, why it’s needed, who prepares it, what it includes, it’s validity, and limitations. We’ll also share a sample of the SOC 1 bridge letter for reference.

What is a SOC 1 Bridge Letter?

A SOC 1 bridge letter, also known as a gap letter, is a short formal document issued by a service organization to extend the coverage of a SOC 1 report.

It outlines the time period between the end of the last audit and the current date, confirming that there have been no significant changes to the organization’s control environment.The letter must include a date range, a statement of no material changes, references to the last Service Organization Control report, and a signature by an authorized executive or compliance officer.

When and why is a SOC 1 Bridge letter used?

A SOC 1 bridge letter is needed when there’s a gap between the end of an audit and your client’s year-end.

For example, let’s say your compliance audit ends in October, but your client’s fiscal year runs through December. Their auditor might start asking, “What happened in those missing months?”

That’s your cue. A bridge letter helps fill that gap and lets them know everything is on track. It assures that there are no big changes, no red flags.

You won’t need it every time, but when someone asks, it’s the fastest way to say, “Yep, we’re still solid. Nothing’s changed since the last report.”

Main Components of the SOC 1 Bridge Letter

Let’s break down the main components of a bridge letter and why each one is important:

Coverage period

The coverage period is the first thing auditors and clients look for. It clearly states the start and end dates not covered by the last SOC 1 report. Basically, the stretch of time the letter is meant to account for.

Material changes

If you’ve made any meaningful updates to your internal processes, systems, or controls since the last audit, it’s important to list them here. This part of SOC 1 gap letter is all about transparency.

Statement of awareness

The organization affirms that no significant changes in control environments, processes, or operations have occurred during the specified bridge period. This declaration assures stakeholders that nothing unexpected or undisclosed has taken place behind the scenes

User responsibility reminder

This is a quick nudge to your customers, reminding them that they still have to hold up their end. It means that they need to follow the user control requirements from the SOC report. In short, this part keeps the risk shared and expectations clear.

Request for review

While the bridge letter stipulates that no major changes have occurred since the last audit, it is important to point your customers in the direction of the full SOC 1 report. The bridge letter is a supplement, not a replacement, so this encourages them to look at the full audit for the complete picture.

Disclaimer

Here’s where you make it clear—a bridge letter doesn’t replace the official SOC 1 report. It’s just meant to cover the in-between period, and that should be clearly stated to avoid confusion.

Limitation of reliance

Finally, include a note saying the letter is just for your customers, not something others must refer to. This protects you from third parties trying to misinterpret what the letter is meant for.

Who writes the SOC 1 bridge letter?

The SOC 1 bridge letter is written by the service organization, not the auditor. After the audit period ends, the CPA firm’s involvement stops, they don’t monitor or validate changes to your environment afterward.

What is the validity of a SOC 1 bridge letter?

A SOC 1 bridge letter is typically valid for upto three months. If the gap between your last SOC audit and the client’s year-end is longer than that, it’s a good idea to consider doing another audit.

Remember, the SOC 1 gap letter isn’t a replacement for a full SOC report, it’s just a short-term patch to keep your clients reassured. It shows them you’re still on top of your controls while they wait for the next official report.

What are the limitations of the SOC 1 bridge letter?

Bridge letters can help fill short gaps, but it’s important to know their limits so you don’t rely on them more than you should. They’re not a replacement for a full audit, and understanding their scope is key.

Limited validity

These letters aren’t meant to stretch across long gaps. Most audit firms and user entities accept them for up to 90 days. Once that reporting period is up or your next SOC report is issued, the letter is no longer relevant.

If there’s a bigger gap, your client might ask for another audit instead of a letter.

Not a replacement for a SOC report

Bridge letters don’t test or verify anything. They don’t include auditor opinion, control testing, or any third-party validation. So, while they offer some coverage, they don’t come close to the depth of a real SOC 1 report. It is more of a stopgap than a safety net.

Minimal assurance

Since the letter comes from the service provider and not the auditor, it’s based on internal representations. It does not contain external validation, so the level of assurance is limited.

Clients get a sense of continuity, but not the confidence that comes with a tested and signed SOC report.

Lack of real-time assurance

Bridge letters don’t offer real-time visibility. They’re based on a fixed point in time and don’t reflect any changes that might happen after they’re signed.

So, if something in your control environment shifts right after the letter goes out, it won’t get flagged until your next audit. That’s a gap worth noting, especially if your business deals with fast-moving systems or high-risk processes.

Stay compliant between audits and beyond

A SOC 1 bridge letter helps you cover those in-between moments when audit periods don’t quite line up. They give your clients confidence that your controls are still in place, even without a fresh audit. Think of it as a way to keep the trust going without having to start from scratch.

While Sprinto doesn’t support SOC 1 today, it’s purpose-built for frameworks like SOC 2, ISO 27001, HIPAA, and more with automation, real-time monitoring, and workflows that align with auditor expectations. So instead of scrambling before every audit, you stay ready year-round.

Want to see what audit-ready, always-on compliance looks like? Book a demo and let Sprinto show you how.

FAQs 

Who writes a bridge letter?

The service organization’s management prepares and signs it, auditors aren’t involved after the SOC report is issued.

Is a SOC 1 bridge letter a replacement for a SOC report?

No, a bridging letter temporarily fills the reporting gap but doesn’t replace a full SOC 1 audit or its detailed assurance.

How long is a bridge letter valid?

Usually a bridge letter is valid up to three months or until the next SOC 1 report is released, whichever comes first.

Who asks for a bridge letter?

Clients or their auditors request it when your SOC report’s coverage doesn’t match their year-end reporting needs.

What does a bridge letter include?

It covers the gap period, confirms no control changes have been made, and is signed by authorized company management.