STIR/SHAKEN statistics from June 2023

The June 2023 STIR/SHAKEN and robocall statistics are now available. The data show a mix of good and bad news.

Many robocalls are signed with B or C attestation

Calls signed with B attestation Were 4.4 Times more likely to be robocalls

Figure 1. Robocall % by Verification Status

Figure 1 compares the percentage of robocalls by attestation level, for unsigned calls, and for all calls in June 2023. Notice that calls signed with B- or C-level attestation include a high percentage of robocalls. Calls signed with B-level attestation were 4.4 times more likely to be robocalls than unsigned calls.

Robocalls signed with B or C attestation increase

Figure 2. Signed Robocalls by Attestation Last 6 Months

Figure 2 shows this trend over the past six months. Notice that robocalls signed with B- or C-level attestation were much higher than the robocall percentage for all calls. The percentage of robocalls among calls signed with C-level attestation has been on a downward trend, from 24.5% in January to 18.6% in June. The percentage of robocalls among calls signed with B-level attestation has been hovering around the 20%–28% range, averaging 22% over the past six months and increasing to 22.9% in June.

SHAKEN participation jumps

We measure STIR/SHAKEN participation changes in three ways:

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

SHAKEN signing up sharply

Figure 3. Monthly Number of OSPs Sending Signed Calls

Figure 3 shows the number of Originating Service Providers (OSPs) signing calls. This had been increasing by about 10/month in previous months. We observed 104 new SHAKEN signers in June, the largest one-month increase we’ve recorded.

The number of SHAKEN-authorized providers increases

Figure 4. STIR/SHAKEN Authorized Providers by Month

Figure 4 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 120 new SHAKEN authorized providers in June, which is also the largest one-month increase we’ve observed.

New Robocall Mitigation Database filings increase

Figure 5. New Robocalls Mitigation Database Filings by Month

Figure 5 shows that new certification filings in the Robocall Mitigation Database increased by 62 in June. This is the largest increase since June 2022, when 108 new RMD certifications were filed.

These three measures show that the STIR/SHAKEN participation is picking up momentum.

Most calls reach their destination unsigned

Most calls arrive unsigned

Figure 6. Percentage of Calls by Verification Status

Figure 6 shows that most calls arrive for termination unsigned in June.

Signed calls at termination up slightly

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

Figure 7 shows the percentage of signed calls at termination for the past six months. This figure had been hovering around 24%. In recent months, we’ve observed this number slowly increasing, reaching 32.9% in June. This is the highest level of signed calls at termination we’ve observed.

However, the increasing percentage of signed calls received at termination is not keeping pace with increasing participation. Since January 2023, the number of OSPs sending signed calls (Figure 3) increased by 41%, while the number of STIR/SHAKEN authorized providers (Figure 4) increased by 40%. Meanwhile, the percentage of signed calls received at termination increased just under 6%, from 27.2% to 32.9% of calls received (Figure 7). We believe this shortfall is because many calls cross a non-IP segment along the call path, where the STIR/SHAKEN information is lost. Out-of-Band SHAKEN can remedy this problem, but it has not been adopted widely enough to make a significant dent in the problem.

Calls with full attestation increase

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

Figure 8 shows that the percentage of calls signed with full attestation has been climbing over the past six months, from 17% in January to 23.4% in June. We view this as one of the most important trends in the set, as full attestations are the most useful for robocall prevention. Unfortunately, our analysis shows that there are problems with A-level attestations made by prolific robocall signers.

Patterns among prolific robocall signers

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

Prolific robocall signers increase robocalls across all attestation levels

Figure 9. Robocall Percentage by Attestation—Prolific Robocall Signers by Robocall %

Figure 9 shows that calls signed with A-level attestation had the highest percentage of robocalls of any attestation level for these providers in March. Since then, the robocall percentage of calls signed with A-level attestation dropped through May but rebounded in June. Robocalls signed by prolific robocall signers increased in June across all attestation levels.

Fewer A-level attestations from prolific robocall signers

Figure 10. Attestation Allocation—Prolific Robocall Signers by Robocall %

Figure 10 shows the attestation allocations for all calls received from these prolific robocall signers. B- and C-level attestations increased slightly, while A-level attestations dropped slightly. However, these changes are subtle—let’s see if this trend continues.

Recap

• Robocalls were up in all categories in June.
• Robocalls signed with B- or C-level attestation remain a problem among the overall population of STIR/SHAKEN signers.
• Robocall percentages among the top 10 prolific robocall signers were up in June across all attestation levels.
• STIR/SHAKEN participation continues to improve.
• The percentage of signed calls received at termination is slowly improving but remains very low and is not keeping pace with increased participation.

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.

Contact us today to learn more.