STIR/SHAKEN statistics from May 2026

May 2026 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 mostly level across attestation levels

Figure 1. Signed Robocalls by Attestation Last 6 Months

Figure 1 shows signed robocalls by attestation level over the past six months. Overall, the statistics were even with April across all attestation levels. Robocalls among all calls were unchanged at 3.4%. Robocalls signed with A-level attestation were unchanged at 1.8%. Robocalls among calls signed with B attestation were down 1.5%. Robocalls among calls signed with C attestation were up 0.5%.

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).

The number of SHAKEN signers was level

Figure 2. Monthly Number of OSPs Sending Signed Calls

Figure 2 shows that the number of Originating Service Providers (OSPs) observed signing calls in May was level, increasing just 0.4% from the previous month. This statistic has not yet recovered from the sharp drop in March.

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 in May was up 1.8% from the previous month.

STIR/SHAKEN coverage

Signed calls at termination increased

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 was up 3.2% in May, to 45.6%. This is a welcome improvement, but still far from the level needed to deliver the full benefits of call authentication.

Calls signed with A-level attestation increased

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

Figure 5 shows the percentage of calls signed by attestation level. The percentage of calls signed with full A-level attestation was 29.8% in May, up 2.2% from April. This accounted for most of the increase in signed calls noted above. The percentage of calls signed with B-level attestation was 3.5%, down 0.2% from April. The percentage of calls signed with C-level attestation was 7.1%, up 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 down

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 level with April. The robocall percentage with A-level attestation was up 0.7%. The robocall percentage with B-level attestation was up 8.7%. The percentage of robocalls with C-level attestation was down 10.0%.

Prolific robocall signers authenticate most calls with A-level attestation

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. In May, 97.4% of the calls authenticated by the top ten prolific robocall signers had an A-level attestation. Almost none had a B-level attestation. 2.6% had a C-level attestation.

Recap

• Robocall percentages were mostly level with April.
• STIR/SHAKEN participation improved, with 0.4% more SHAKEN signers and 1.8% more authorized providers.
• STIR/SHAKEN coverage increased 3.2%, to 45.6%. This is a welcome improvement, but still far below the level necessary to leverage call authentication information effectively.
• Robocalls authenticated by prolific robocall signers were at the same level as in April. They continue to sign 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.