STIR/SHAKEN statistics from November 2023

The November 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 894 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 attestation increase

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. Robocalls signed with B-level attestation increased by 2.6%, while robocalls with A- and C-level attestation dropped. The overall robocall percentage was level.

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 24 new SHAKEN signers in November, a 2.8% 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 only 8 new SHAKEN authorized providers in November, a 0.6% 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 November.

Signed calls at termination stall

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 low, 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 down

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. This had been climbing over the past six months, reaching 24.5% in July. This figure dropped again to 21.2% in November.

box 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 send many robocalls with A- and B-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 was down slightly, to 83.6% in November, but remains remarkably high.

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


  • Overall robocalls were down.
  • Robocalls signed with a B-level attestation were up, while other robocalls were down.
  • The top 10 prolific robocall signers signed a higher percentage of robocalls with B-level attestation. Their robocalls signed with either A- or C-level attestation were down slightly.
  • 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.

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