STIR/SHAKEN statistics from August 2026

August 2026 STIR/SHAKEN and robocall statistics are now available. The data show the latest trends in robocalls, STIR/SHAKEN participation, and attestation level usage. Let's have a look.

Signed robocalls by attestation level

Robocalls mostly level across attestation levels

Figure 1. Signed Robocalls by Attestation Last 6 Months

Figure 1 shows signed robocalls by attestation level over the past six months. Overall, the statistics in August were mostly level with July across all attestation levels. Robocalls among all calls were 3.2%, down from 3.5% in July. Robocalls signed with A-level attestation were 1.6%, down 0.1%. Robocalls among calls signed with B attestation were 3.8%, down 1.4% from July. Robocalls among calls signed with C attestation were 7.8%, down 0.9% from July.

STIR/SHAKEN participation and coverage

We measure STIR/SHAKEN participation changes in two ways:

1. The number of Originating Service Providers (OSPs) signing calls received by our customers,
2. Service providers authorized to do SHAKEN by the STI Policy Administrator (STI-PA).

The number of SHAKEN signers was down slightly

Figure 2. Monthly Number of OSPs Sending Signed Calls

Figure 2 shows that the number of Originating Service Providers (OSPs) observed signing calls in August was down 0.1% from the previous month.

The number of SHAKEN-authorized providers increased

Figure 3. STIR/SHAKEN Authorized Providers by Month

Figure 3 shows that the number of SHAKEN-authorized providers in August was up 1.6% from the previous month.

STIR/SHAKEN coverage

Signed calls at termination increased slightly

Figure 4. The Percentage of Signed Calls at Termination Last 6 Months

Figure 4 shows the percentage of signed calls at termination for the past six months. This was up 0.5% in August, to 54.8%. This is the highest percentage of signed calls we've seen, but far from the level needed to deliver the full benefits of call authentication.

Calls signed with A-level attestation increased slightly

Figure 5. Percentage of Calls with SHAKEN Attestation Levels Last 6 Months

Figure 5 shows the percentage of calls signed by attestation level. The percentage of calls signed with full A-level attestation was 33.8% in August, nearly level with July. The percentage of calls signed with B-level attestation was 5.7%, down 0.5% from July. The percentage of calls signed with C-level attestation was 8.0%, nearly level with July.

Patterns among prolific robocall signers

Here are robocall and attestation statistics for the top 10 SHAKEN-authorized providers ranked by the percentages of signed calls identified as robocalls.

Robocalls from prolific robocall signers decreased

Figure 6. Robocall Percentage by Attestation—Prolific Robocall Signers by Robocall %

Figure 6 shows robocalls authenticated by the top 10 robocall signers ranked by robocall percentage over the past six months.

In August, the robocall percentage among prolific robocall signers was down 4.6% from July. The robocall percentage with A-level attestation was down 5.8%. We observed almost no calls or robocalls signed with a B-level attestation. There was a jump in calls signed with C-level attestation, and 69% of these were robocalls.

Prolific robocall signers authenticate most calls with A-level attestation

Figure 7. Call Percentage by Attestation—Prolific Robocall Signers

Figure 7 shows the percentages of calls signed by the top 10 robocall signers by authentication level. In August, 71% of the calls authenticated by the top ten prolific robocall signers had an A-level attestation. Very few had a B-level attestation. 27% had a C-level attestation.

Recap

• Robocall percentages were mostly even with July.
• STIR/SHAKEN participation improved slightly. The number of SHAKEN signers was level, and the number of authorized providers increased 1.6%.
• STIR/SHAKEN coverage increased 0.5%, to 54.8%. Great news, but still a long way to go.
• Robocalls authenticated by prolific robocall signers decreased from July. They signed most calls with an A-level attestation, while very few had a B-level attestation, and 27% had a C-level attestation.

TransNexus solutions

TransNexus is a leader in developing innovative software to manage and protect telecommunications networks worldwide. The company has over 25 years of experience in providing telecom software solutions, including toll fraud prevention, robocall mitigation and prevention, CDR and call analytics, advanced call routing, billing support, STIR/SHAKEN, and branded calling.

Contact us today to learn more.