Why Your Calls Show Up As Spam — And How Stir/shaken Helps Fix It

By Author: Hodusoft
Total Articles: 21
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For many businesses, the first point of contact with customers is still a phone call. However, when your caller ID displays “Spam Likely” or “Scam Risk,” that simple outreach becomes a challenge. Customers hesitate to answer, your pickup rates drop, and your brand credibility takes a hit.
A major reason behind this problem is caller ID spoofing, and the telecom industry’s recommended solution is a framework known as STIR/SHAKEN.
In the sections below, we’ll examine why legitimate calls are mislabeled, what STIR/SHAKEN actually does, and how adopting it can help restore trust in your outbound calls.
Why Real Business Calls Sometimes Get Tagged as Spam

High outbound volume:
Companies that dial large lists — sales teams, support centers, delivery notifications — often get flagged simply because the call frequency looks suspicious to carriers.
Spoofing problems:
Scammers frequently imitate real business numbers. As a result, carriers apply stricter ...
... filters, and occasionally genuine numbers get caught in the mix.
Damaged number reputation:
Once a number is flagged, it may continue to be treated as suspicious even if the business behind it is legitimate. This reputation issue can discourage people from answering in the future.

Understanding STIR/SHAKEN
STIR stands for Secure Telephone Identity Revisited, while SHAKEN expands to Signature-based Handling of Asserted information using toKENs.
Put simply, both work together to prove that a call is coming from the number it claims to be. This is done using a system of digital certificates and cryptographic signatures that help carriers verify caller identity.
As part of the process, calls receive an attestation level, which indicates how confident the originating carrier is about the caller:
A-Level (Full Attestation): The caller’s identity and number ownership are fully verified.
B-Level (Partial Attestation): The caller is known, but the carrier cannot confirm they own the number.
C-Level (Gateway Attestation): The call comes through an external or less-trusted network, so verification is minimal.
A Simple Look at How STIR/SHAKEN Works

Call Origination The call begins with the originating carrier reviewing the number and confirming the caller’s identity.
Digital Certificate Signing If everything checks out, the carrier signs the call using an approved digital certificate.
Transmission Through the Network The call and its signature travel together across networks.
Verification on the Recipient’s Side The receiving carrier examines the signature to determine if the call is genuine.
Based on verification, the call may be flagged, blocked, or displayed with a “Verified” indicator on the customer’s device.

What STIR/SHAKEN Can Solve — And What It Can’t
What It Helps With

Prevents spoofing: Only calls signed by authorized carriers are trusted.
Improves analytics accuracy: Verification gives spam-filtering systems more confidence.
Enhances brand trust: Calls with full attestation (A-level) are far less likely to be marked as spam.

Where It Falls Short

Doesn’t filter content: A call can still be unwanted even if it’s verified.
Depends on certificate infrastructure: The system requires reliable public-key management.
Not universally adopted: Some carriers and regions are still catching up.

Why Businesses Should Consider STIR/SHAKEN
Higher answer rates
Customers feel more secure answering calls marked as “Verified,” which leads to better engagement.
Fewer blocked or filtered calls
With proper attestation, your outbound numbers are less likely to be flagged by carrier spam systems or call-blocking apps.
A more credible brand image
Adopting STIR/SHAKEN demonstrates your organization's commitment to transparency and safe communication practices.
Getting Started With STIR/SHAKEN

Talk to your service provider
Your VoIP or call center software provider can tell you whether they support STIR/SHAKEN and what attestation level they offer for your numbers.
Confirm your number ownership
Make sure your business numbers are properly registered and easily verifiable.
Monitor your call performance
Track metrics such as answer rates and spam labels after enabling STIR/SHAKEN to measure improvements.
Inform your customers
Let customers know your calls will now appear as verified — this small step often improves trust.

Final Thoughts
Caller ID spoofing has created major challenges for businesses that rely on phone outreach. While no system is perfect, STIR/SHAKEN provides a strong layer of caller authentication that helps reduce spam labels, boost answer rates, and build confidence with your audience.
Implementing it is a meaningful step toward maintaining a trustworthy caller identity and ensuring that your calls reach the people who need to hear from you.
To know more, visit: https://hodusoft.com/why-calls-are-marked-spam-fix-with-stir-shaken/