STIR/SHAKEN statistics from May 2025

May 2025 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 down slightly

Figure 1. Signed Robocalls by Attestation Last 6 Months

Figure 1 shows signed robocalls by attestation level over the past six months. The statistics were changed only slightly from April. Robocalls among all calls were down 0.4% from April. Robocalls signed with A-level attestation were up 0.1%. Robocalls among calls signed with B attestation were down 1.4%, while robocalls among calls signed with C attestation were down 0.6%.

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),

Slightly more SHAKEN signers

Figure 2. Monthly Number of OSPs Sending Signed Calls

Figure 2 shows the number of Originating Service Providers (OSPs) observed signing calls in May was up 1.4% from April.

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 was up 3.7% in May, reaching an all-time high of 1,485.

STIR/SHAKEN coverage

Signed calls at termination down 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 dropped 0.2% in May, to 42.3%. This statistic has been on a downward trend since October 2024, when it peaked at 49.3%. We believe that this statistic remains low because of non-IP segments in the service provider voice network.

Signed calls level across attestation levels

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

Figure 5 shows the percentage of calls signed by attestation level. Calls signed with full A-level attestation were 28.8% in May, up 0.3% from April. Calls signed with B-level attestation were 3.3%, down 0.1% from April. Calls signed with C-level attestation were 7.3%, down 0.6% from April.

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 increased

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 May, the robocall percentage among prolific robocall signers was up 1.5% across all attestation levels. Robocalls with A-level attestation were up 3.0%. Robocalls with B-level attestation dropped 14.8%. Robocalls with C-level attestation increased by 11.5%.

Calls from prolific robocall signers

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. They continue to sign their calls mostly with A-level attestation.

We encourage terminating service providers and call analytics providers to incorporate SHAKEN signer reputation into their call analytics. We provided examples in a blog post, How to monitor SHAKEN signer reputation.

Recap

• Robocalls were down slightly from April.
• STIR/SHAKEN participation continues a gradual upward trend.
• STIR/SHAKEN coverage has been in steady decline since October 2024. For the past four months, roughly 42% of calls arrive at termination with call authentication information intact. This is way too low for STIR/SHAKEN to be effective.
• We suspect that many calls are being routed across non-IP segments in the call path, where SHAKEN information is lost.
• The percentage of robocalls signed by the top 10 prolific robocall signers was up 1.5% across all attestation levels. These signers continue to authenticate most calls with A-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.