STIR/SHAKEN statistics from January 2023

We see some encouraging trends in the latest STIR/SHAKEN statistics, along with some lingering concerns. Let’s have a look.

We’ve been publishing monthly STIR/SHAKEN statistics since April 2021. These numbers are gathered from over 100 voice service providers using our STIR/SHAKEN and robocall prevention solutions. The data describe calls they received from 522 other voice service providers that originated calls, including some robocalls, signed with STIR/SHAKEN.

Many Robocalls are signed with B or C attestation

Calls Signed with B or C Were Over 3.5 Times More Likely to be Robocalls

bar chart showing robocalls by SHAKEN verification status

Figure 1. Robocall % by Verification Status in January 2023

Figure 1 compares the percentage of robocalls by attestation level, for unsigned calls, and for all calls in January 2023.

The red line shows the robocall percentage for all calls, which was 8.35%. Robocalls were 7.79% of unsigned calls. We continue to see a significant number of robocalls among calls signed with either a B or C attestation—more than 3.5 times the percentage of robocalls among unsigned calls.

Signed Robocalls Down in January

line chart comparing robocall attestations over 6 months

Figure 2. Signed Robocalls by Attestation Last 6 Months

Figure 2 shows this trend over the past six months. Robocalls signed with B attestation were down 2.97% from December. Robocalls signed with C attestation were down 3.75% in January.

SHAKEN participation continues to level off

We measure STIR/SHAKEN participation changes in three ways:

  1. The number of Originating Service Providers (OSPs) signing calls received by our customers
  2. The number of service providers authorized to do SHAKEN by the STI Policy Administrator (STI-PA)
  3. The number of new certification filings in the Robocall Mitigation Database

SHAKEN Participation Leveling

line chart showing a slight increase in SHAKEN participation

Figure 3. Monthly Number of OSPs Sending Signed Calls

Figure 3 shows that the number of Originating Service Providers (OSPs) signing calls increased slightly from 507 in December to 522 in January, up 3.0%. This follows a 0.83% decrease in December.

SHAKEN Authorized Providers Increases Slightly

line chart showing a slight increase in SHAKEN participation

Figure 4. STIR/SHAKEN Authorized Providers by Month

Figure 4 shows that the number of SHAKEN authorized providers increased by 3.6% in January, from 806 to 835. This follows a 1.4% increase in December.

New Robocall Mitigation Database Filings Up Slightly

bar chart showing most calls are unsigned

Figure 5. New Robocalls Mitigation Database Filings by Month

Figure 5 shows that there were 44 new Robocall Mitigation Filings in January, a 46.7% increase from December. The January figure is in line with trends in August through November. December was an outlier.

Few calls reach their destination signed

Most Calls Arrive Unsigned

bar chart showing most calls are unsigned

Figure 6. Percentage of Calls by Verification Status

Figure 6 shows that 72.81% of calls received for termination were unsigned, up slightly from December, when 73.84% of calls were unsigned.

Percentage of Signed Calls at Termination Was Up Slightly

line chart showing a slight increase in signed calls

Figure 7. The Percentage of Signed Calls at Termination Last 6 Months

Figure 7 shows that the percentage of signed calls at termination was 27.19%, a 1.03% increase from 26.16% in December. The percentage of signed calls has been stuck around 24% since August 2021, despite the steady increase in Originating Service Providers and SHAKEN authorized providers signing calls at origination. It’s great to see a steady improvement, which has averaged 0.94% per month since September 2022.

Few calls receive a full attestation

STIR/SHAKEN is most useful when call signers have an authenticated relationship with the caller and calling number. This enables the originator to sign the call with full A-level attestation. This makes call analytics by downstream providers much more useful.

Few Calls Are Signed with Full Attestation

few calls are signed with full attestation

Figure 8. Percentage of Calls with SHAKEN Attestation Levels Last 6 Months

The percentage of calls signed with full attestation was around 20% at the start of 2022. It gradually declined through the first half of 2022, reaching 15.33% in August. Figure 8 shows that it slumped slightly in January to 16.91% from 17.06% in November.

waterfall chart


  1. Signed robocalls continue, as robocall-friendly providers have their calls signed by downstream third-party signers using their own SHAKEN certificate.
  2. We see participation leveling off while the percentage of signed calls has s-l-o-w-l-y improved by almost 1% per month since September.
    1. We expect a big jump in participation as providers come online approaching the June 30 deadline.
  3. A-level attestation remains stuck around 17%, undermining the usefulness of call authentication.

TransNexus solutions

TransNexus is a leader in developing innovative software to manage and protect telecommunications networks. The company has over 20 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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