STIR/SHAKEN statistics from October 2023

The October 2023 STIR/SHAKEN and robocall statistics are now available. The data show the latest trends in robocalls, STIR/SHAKEN participation and attestation level usage.

We’ve been publishing monthly STIR/SHAKEN statistics since April 2021. These numbers are gathered from well over a hundred voice service providers using our STIR/SHAKEN and robocall prevention solutions. The data describe calls they received from 870 other voice service providers that originated calls, including some robocalls, signed with STIR/SHAKEN.

Many robocalls are signed with B or C attestation

Robocalls signed with B and C attestation remain high

Line chart comparing robocall attestations over 6 months

Figure 1. Signed Robocalls by Attestation Last 6 Months

Figure 1 shows robocalls by attestation level over the past six months. There was a sharp increase in robocalls signed with B- or C-level attestation in September. Robocalls mostly remained at these higher levels in October.

STIR/SHAKEN participation

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),

SHAKEN signing leveling off

line chart showing the number of originating providers sending signed calls

Figure 2. Monthly Number of OSPs Sending Signed Calls

Figure 2 shows the number of Originating Service Providers (OSPs) signing calls. We observed 20 new SHAKEN signers in October, a 2.4% increase.

The number of SHAKEN-authorized providers leveling off

line chart showing an increase in SHAKEN participation

Figure 3. STIR/SHAKEN Authorized Providers by Month

Figure 3 shows the number of SHAKEN authorized providers. As with OSP signers, this number has an upward trend that has been increasing in recent months. There were 20 new SHAKEN authorized providers in October, a 1.6% increase.

These two measures show that the STIR/SHAKEN participation has leveled off.

STIR/SHAKEN coverage

STIR/SHAKEN call authentication will be more useful as the percentage of signed calls received at termination and calls with full A-level attestation increases. We had been observing slow, steady improvement over the past six months, but both measures of coverage were down in September and rebounded only slightly in October.

Signed calls at termination leveling off

line chart showing the percentage of signed calls received at termination

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 figure remains stuck at around 31-32%. We believe that the primary reason for low STIR/SHAKEN coverage is widespread non-IP interconnections across the telephone network.

Calls with full attestation up slightly

line chart showing the percentage of calls received at termination by attestation level

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

Figure 5 shows the percentage of calls signed with full attestation. had been climbing over the past six months, reaching 24.5% in July. This figure peaked in July, dropped in August, and has been slowly regaining ground, reaching 23.4% in October.

line and whiskers chart concept

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.

Prolific robocall signers increase robocalls with A-level attestation

robocalls among calls with A-level attestation are increasing

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

Figure 6 shows robocalls authenticated by prolific robocall signers over the past six months. Notice the steady increase in the percentage of robocalls among calls they sign with full A-level attestation. This figure reached 86.2% in October.

This is also the first month in which calls signed with A-level attestation by prolific robocall signers had the highest percentage of robocalls of any attestation level.

We believe that terminating providers should evaluate the reputation of STIR/SHAKEN signers and use it as an input to call validation treatment.


  • Robocalls signed with either a B- or C-level attestation remain high after a sharp increase in September.
  • The top 10 prolific robocall signers signed a higher percentage of robocalls with A-level attestation than any other attestation level.
  • STIR/SHAKEN participation and coverage remain level.

TransNexus solutions

TransNexus is a leader in developing innovative software to manage and protect telecommunications networks. The company has over 25 years’ experience in providing telecom software solutions including toll fraud prevention, robocall mitigation and prevention, TDoS prevention, analytics, routing, billing support, STIR/SHAKEN and SHAKEN certificate services.

Contact us today to learn more.

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