Only 54.8% of US phone calls reached the terminating carrier with a STIR/SHAKEN signature in August 2026 (TransNexus, STIR/SHAKEN statistics August 2026). That clears the October 2024 peak of 49.3% after a slide to 38.4% in August 2025, yet attestation alone still does not separate good calls from bad: 71% of calls from the ten most prolific robocall signers carried the top A-level attestation that month. The ecosystem itself has grown fast, with more than 1,900 participating providers (STI-GA, 2025 SHAKEN Report), while YouMail still counted 52.5 billion US robocalls in 2025. For the broader volume picture see our robocall statistics. We aggregated data from TransNexus, the FCC, the STI-GA, TNS, YouMail, the FTC, Hiya, Arcep, Ofcom, India’s Department of Telecommunications and the CRTC.
TL;DR
- 54.8% of US calls arrived signed at termination in August 2026, up from 38.4% in August 2025 (TransNexus, monthly STIR/SHAKEN statistics).
- 33.8% of calls at termination carried full A-level attestation in August 2026 (TransNexus, August 2026).
- About 84% of call traffic between major US voice providers was signed and verified by mid-2025 (FCC, STIR/SHAKEN Triennial Report, December 2025).
- Only 17.5% of signed traffic between smaller carriers versus 85% between Tier-1 carriers (TNS, 2026 Robocall Report).
- More than 1,900 providers participate in STIR/SHAKEN, up from 74 authorized in early 2021 (STI-GA 2025 SHAKEN Report; FCC Triennial Report).
- Nearly 3,500 domestic providers certify full implementation and about 1,400 partial, out of over 9,000 RMD filers (FCC Triennial Report, December 2025).
- 71% of calls from the top ten prolific robocall signers carried A-level attestation (TransNexus, August 2026).
- Scams are A-level attested over 50% of the time in TNS honeypot data (TNS, cited in FCC Triennial Report).
- 1,200+ providers removed from the Robocall Mitigation Database on August 25, 2025 (FCC Final Removal Order, via Wiley).
- 52.5 billion US robocalls in 2025, less than 1% below 2024 (YouMail Robocall Index).
- Over 2.6 million Do Not Call complaints to the FTC in FY2025, about 48% below FY2021 (FTC, DNC Data Book FY2025).
- India’s spoofed international calls with Indian numbers fell 97% after a 2024 network-level filter (DoT, via ANI, July 2025).
1. Signed Call Coverage: Back Above Half, Five Years In
Coverage is the number that tells you whether the framework is working end to end, and for most of 2025 it was going backwards. TransNexus measured 54.8% of calls signed at termination in August 2026, after a slide from a 49.3% peak in October 2024 to 42.3% in May 2025 and 38.4% in August 2025 (TransNexus, August 2026). The rebound coincides with the FCC’s third-party authentication rule, which took effect on September 18, 2025 and forced providers to sign with their own SPC token and certificate (Herman Whiteaker, on FCC 24-120).
The A-level line moved with it, from 26.5% of terminating calls in August 2025 to 33.8% a year later. Put plainly: almost half of US calls still reach the handset with no verifiable signature at all, which is why carrier analytics and call labeling, not STIR/SHAKEN alone, still decide what gets a spam warning.
| Metric | Value | Source |
|---|---|---|
| Calls signed at termination, October 2024 (prior peak) | 49.3% | TransNexus, STIR/SHAKEN statistics May 2025 |
| Calls signed at termination, May 2025 | 42.3% | TransNexus, May 2025 |
| Calls signed at termination, August 2025 | 38.4% | TransNexus, August 2025 |
| Calls signed at termination, February 2026 | 44.5% | TransNexus, February 2026 |
| Calls signed at termination, June 2026 | 48.8% | TransNexus, June 2026 |
| Calls signed at termination, August 2026 | 54.8% | TransNexus, August 2026 |
| A / B / C attestation share of terminating calls, August 2026 | 33.8% / 5.7% / 8.0% | TransNexus, August 2026 |
| A / B / C attestation share, August 2025 | 26.5% / 3.2% / 6.2% | TransNexus, August 2025 |
Context note: TransNexus month-over-month changes are published as point moves on its own customer traffic sample, not a census of all US calls. Earlier monthly reads are in the February 2026 and May 2025 reports.
2. Where Signatures Get Lost: Big Carriers vs the Long Tail
The headline coverage hides two very different networks. About 84% of all call traffic between major US voice providers was signed and verified by mid-2025 (FCC, STIR/SHAKEN Triennial Report, December 2025), and TNS puts Tier-1 to Tier-1 signing at 85%, with 93% of that at A-level (TNS 2026 Robocall Report). Between smaller carriers the figure collapses to 17.5%.
The cause is mostly plumbing. STIR/SHAKEN rides on SIP, so a signature disappears the moment a call crosses a TDM link. The FCC cites an industry estimate that more than 60% of calls signed by the originating provider arrive without attestation details, and TNS estimates about 40% of TDM bypass traffic lacks signatures. The FCC’s April 2025 non-IP proposal would give legacy networks two years to move to IP or adopt one of the ATIS non-IP frameworks. Business VoIP traffic, which our VoIP and UCaaS statistics show is now the default for most companies, signs far less reliably than wireless and wireline calls.
| Metric | Value | Source |
|---|---|---|
| Traffic between major US providers signed and verified, mid-2025 | About 84% | FCC Triennial Report, December 2025 |
| Tier-1 to Tier-1 traffic signed and verified, 2025 | 85% (93% of it A-level) | TNS 2026 Robocall Report |
| Signed traffic between smaller carriers, 2025 | 17.5% | TNS 2026 Robocall Report |
| Wireless/wireline vs VoIP calls passing STIR/SHAKEN, top carriers | 85% vs 35% | TNS 2026 Robocall Report |
| Wireless/wireline vs VoIP calls passing STIR/SHAKEN, smaller carriers | 21% vs 13% | TNS 2026 Robocall Report |
| Calls signed at origin that lose attestation by termination | More than 60% (industry estimate) | FCC Triennial Report, December 2025 |
| TDM bypass traffic without signatures | About 40% | TNS 2026 Robocall Report |
| Sample of 200,000+ calls with useful signatures, November 2025 | 71% (81% on a narrower basis) | FCC Triennial Report, December 2025 |
Context note: the 84% (FCC) and 54.8% (TransNexus) figures do not conflict. The first measures traffic exchanged among large providers, the second measures all calls reaching TransNexus customers at termination, which includes small, rural and non-IP paths.
3. Attestation Abuse: When A-Level Signs a Robocall
Attestation is meant to tell the receiving network how much the originating carrier knows about the caller. The data shows it does carry signal: in August 2026, 1.6% of A-attested calls were robocalls, against 3.8% for B and 7.8% for C (TransNexus, August 2026). But the providers that sign the most robocalls lean on the highest grade. Among the ten most prolific robocall signers, 71% of calls carried A-level attestation in August 2026, after 97.4% in June 2026 (TransNexus, June 2026) and 93.4% in August 2025.
Independent traffic analysis points the same way. TNS honeypot data shows scams are A-level attested over 50% of the time, and 43% of spam in TNS production traffic is A-attested, the FCC’s triennial report notes, while TNS finds up to 13% of traffic using invalid numbers signed A. The most cited case is the 2024 New Hampshire primary, where AI-cloned Biden robocalls carried top-level attestation and Lingo Telecom settled for $1 million (RCR Wireless, August 2024); our deepfake election statistics cover the wider pattern. The FCC’s 2026 proposal to codify A, B and C criteria is aimed squarely at this gap.
| Metric | Value | Source |
|---|---|---|
| Robocalls among all calls, August 2026 | 3.2% (3.5% in July) | TransNexus, August 2026 |
| Robocall rate by attestation, August 2026 (A / B / C) | 1.6% / 3.8% / 7.8% | TransNexus, August 2026 |
| Robocall rate by attestation, June 2026 (A / B / C) | 1.9% / 6.4% / 8.4% | TransNexus, June 2026 |
| Top ten prolific robocall signers using A-level | 71% (August 2026), 97.4% (June 2026), 93.4% (August 2025) | TransNexus monthly reports |
| Scams A-level attested in honeypot data | Over 50% | TNS, cited in FCC Triennial Report 2025 |
| Spam in production traffic that is A-attested | 43% | TNS, cited in FCC Triennial Report 2025 |
| Invalid-number traffic signed with A-attestation | Up to 13% | TNS 2026 Robocall Report |
| Signed traffic showing over-attestation in some networks | As much as 20% | TNS 2026 Robocall Report |
Context note: the August 2025 prolific-signer figure is from TransNexus, August 2025. The Lingo settlement dates from 2024 and is shown as historical context (most recent available case of its kind with a public fine).
4. Ecosystem Growth: From 74 Providers to 1,900+
Participation is no longer the bottleneck it was. In early 2021 only 74 providers were authorized to receive SPC tokens; by late 2025 more than 1,800 were, the FCC reports, and the STI-GA counts more than 1,900 participating providers in its 2025 SHAKEN Report. More than 550 joined between June and the end of September 2025, the window when the third-party signing rule was about to bite. TransNexus monthly counts show the same jump, from 1,485 authorized providers in May 2025 to 1,739 in August 2025.
The paperwork tells a less tidy story. Nearly 3,500 domestic providers certify full STIR/SHAKEN implementation in the Robocall Mitigation Database and about 1,400 partial implementation, out of over 9,000 RMD filers (FCC Triennial Report). Before the third-party rule, a TransNexus estimate cited by the FCC found about 64% of RMD filers claiming STIR/SHAKEN were not registered with the Policy Administrator (FCC 24-120), meaning they relied on someone else’s certificate.
| Metric | Value | Source |
|---|---|---|
| Providers authorized by the STI-PA, early 2021 | 74 | FCC Triennial Report, December 2025 |
| SHAKEN-authorized providers, May 2025 | 1,485 | TransNexus, May 2025 |
| SHAKEN-authorized providers, August 2025 | 1,739 | TransNexus, August 2025 |
| Providers authorized to receive tokens, late 2025 | More than 1,800 | FCC Triennial Report, December 2025 |
| Participating providers, 2025 | More than 1,900 (550+ added June to September) | STI-GA 2025 SHAKEN Report |
| Providers certifying full / partial implementation (November 18, 2025) | Nearly 3,500 / about 1,400 | FCC Triennial Report, December 2025 |
| RMD filers claiming STIR/SHAKEN but not registered with the PA (pre-rule) | About 64% | TransNexus, cited in FCC 24-120 (November 2024) |
| Authorized certificate authorities (STI-CAs) | 15, one shut down in 2025, none added | STI-GA 2025 SHAKEN Report |
Context note: the 64% estimate predates the September 2025 compliance date and should not be read as current. TransNexus reported authorized providers up another 1.6% month over month in August 2026 but no longer publishes the absolute count in each report.
5. FCC Enforcement: The Robocall Mitigation Database Gets Teeth
The RMD is the FCC’s lever: a provider removed from it must be cut off by every other carrier. On August 25, 2025, the Enforcement Bureau removed more than 1,200 providers in a single order, after 185 removals on August 6 and a December 2024 show-cause order to 2,411 providers (Wiley, August 2025). Other carriers had until August 27, 2025 to stop accepting their traffic. On September 2, 2026 the FCC removed 14 more companies, all of which had already been ordered to cure deficiencies.
Token revocation has been far rarer than database removal. The STI-GA says only seven providers faced SPC token revocation at the end of 2025 after their RMD filings were deleted. The 2026 rulemakings point to a stricter phase: proposed base forfeitures of $2,500 per call for know-your-upstream-provider violations and $1,000 per call for improper attestations (Davis Wright Tremaine, June 2026), a July 2026 RMD proposal requiring 24-hour traceback responses (Wiley, July 2026), and a September 2026 public notice on a consumer-facing robocall scorecard for providers (TransNexus, September 2026).
| Metric | Value | Source |
|---|---|---|
| Providers ordered to cure deficient RMD filings | 2,411 (December 2024) | FCC Show Cause Order DA-24-1235, via Wiley |
| Providers removed, Initial Removal Order | 185 (August 6, 2025) | FCC DA-25-694, via Wiley |
| Providers removed, Final Removal Order | More than 1,200 (August 25, 2025) | FCC DA-25-737, via Wiley |
| Providers removed, September 2026 | 14 (September 2, 2026) | FCC Enforcement Bureau, September 2026 |
| Providers facing SPC token revocation after RMD deletion | 7 (end of 2025) | STI-GA 2025 SHAKEN Report |
| Providers claiming the undue-hardship extension | 1.13% of RMD filers | FCC Triennial Report, December 2025 |
| Proposed base forfeiture, KYUP violations / improper attestation | $2,500 / $1,000 per call | FCC 26-32 FNPRM, via Davis Wright Tremaine |
| Proposed traceback response deadline | 24 hours | FCC 26-49 FNPRM, via Wiley |
Context note: Wiley also reports that 37 providers received Operation Robocall Roundup warning letters, 7 of which overlapped with the August 2025 initial removals. The 2026 forfeiture amounts are proposals, not adopted rules.
6. The Consumer Outcome: Fewer Complaints, Same Robocall Volume
Five years of authentication have not shrunk the robocall total. YouMail counted 52.5 billion US robocalls in 2025, less than 1% below 2024’s 52.8 billion, and unwanted telemarketing and scam calls rose 15.4% to 57% of the total (YouMail Robocall Index, January 2026). August 2026 offered the first real dip: just under 3.9 billion calls, down 10% from July, putting the trailing 12-month total at 48.5 billion, the lowest since August 2022 (YouMail, August 2026).
Complaints tell a better story. The FTC received over 2.6 million Do Not Call complaints in FY2025, about 48% fewer than the roughly five million in FY2021 (FTC, DNC Data Book FY2025). But consumers do not feel safer: Hiya’s survey of more than 12,000 people in six countries found Americans receive 9.9 unwanted calls a week, 86% of unknown calls go unanswered, and Americans think scammers are beating mobile operators by nearly 2 to 1 (Hiya, State of the Call 2026). Our phone call statistics show how that distrust has changed answer rates.
| Metric | Value | Source |
|---|---|---|
| US robocalls, 2025 | 52.5 billion (52.8 billion in 2024) | YouMail Robocall Index, January 2026 |
| Telemarketing and scam share of robocalls, 2025 | 57% (up from 49%), +15.4% volume | YouMail Robocall Index, January 2026 |
| US robocalls, August 2026 | Just under 3.9 billion (125.4 million per day) | YouMail Robocall Index, September 2026 |
| Trailing 12-month robocalls, August 2026 | 48.5 billion (lowest since August 2022) | YouMail Robocall Index, September 2026 |
| FTC Do Not Call complaints, FY2025 | Over 2.6 million (about 48% below FY2021) | FTC, DNC Data Book FY2025 |
| Active Do Not Call registrations | About 258.5 million (September 30, 2025) | FTC press release, December 2025 |
| FCC unwanted call complaints, FY2021 to FY2024 | 151,500 to 120,800 (-20%) | FCC Triennial Report, December 2025 |
| Unwanted calls per week, US / global average | 9.9 / 7.4 | Hiya State of the Call 2026 |
Context note: the FTC release on the FY2025 Data Book lists debt reduction, imposters and medical calls as top complaint topics. Hiya also found 1 in 4 Americans received a deepfake voice call in the past 12 months, a threat our AI voice scam statistics track in detail.
7. Beyond the US: France, the UK, India and Canada
Other regulators are taking different routes to the same problem, often with blunter tools. France’s MAN authentication mechanism started on mobile numbers in late 2024 and extended to landlines in early 2025. Arcep expected more than 80% of calls made by French subscribers while roaming to be authenticated by end of 2025, and from January 1, 2026 operators must mask French mobile numbers arriving from abroad that cannot be authenticated (Arcep, Decision 2025-2215, December 2025). Spoofing reports on its platform went from 531 in 2023 to 8,500 in 2024 and more than 19,000 in 2025 (Next, January 2026).
The UK and India skipped full cryptographic signing for now and filter at the border. Ofcom’s landline anti-spoofing rule took effect on January 29, 2025, and Ofcom said existing measures were blocking about one million calls a day (Mobile ID World, July 2025); in July 2026 it extended the approach to UK mobile numbers roaming abroad (TelecomLead, July 2026). India’s DoT filter blocked 13.5 million (1.35 crore) spoofed calls in its first 24 hours and cut daily volume by 97% to about 300,000 (Tribune India, July 2025). Canada mandated STIR/SHAKEN in 2021, and the CRTC replaced semi-annual status reports with targeted inquiries in Decision 2025-343 on December 16, 2025 (CommLaw Group).
| Metric | Value | Source |
|---|---|---|
| France: roaming calls by French subscribers authenticated | More than 80% expected by end of 2025 | Arcep, Decision 2025-2215 |
| France: number spoofing reports to J’alerte l’Arcep | 531 (2023), 8,500 (2024), 19,000+ (2025) | Arcep data via Next, January 2026 |
| France: masking of unauthenticated French mobile CLIs from abroad | From January 1, 2026 | Arcep, December 2025 |
| UK: calls blocked by anti-spoofing measures | About one million per day | Ofcom, via Mobile ID World, July 2025 |
| UK: losses to fraud in 2025 | 1.28 billion pounds | TelecomLead, July 2026 |
| India: spoofed calls blocked in first 24 hours (October 2024) | 13.5 million (1.35 crore) | DoT, via ANI/Tribune India, July 2025 |
| India: reduction in spoofed calls with Indian numbers | 97% (to about 300,000 per day) | DoT, via ANI/Tribune India, July 2025 |
| India: international carriers and aggregators blocked | 308 | DoT, via ANI/Tribune India, July 2025 |
Context note: France and the UK publish targets and blocking volumes rather than a signed-call share comparable to TransNexus data. The Canadian annual reports due May 31, 2026 were not public at the time of writing.
Summary: STIR/SHAKEN Caller ID Authentication by the Numbers
| Metric | Value | Source |
|---|---|---|
| US calls signed at termination | 54.8% (August 2026) | TransNexus |
| Calls signed at termination a year earlier | 38.4% (August 2025) | TransNexus |
| A-level share of terminating calls | 33.8% (August 2026) | TransNexus |
| Traffic between major providers signed and verified | About 84% (mid-2025) | FCC Triennial Report |
| Signed traffic between smaller carriers | 17.5% | TNS 2026 Robocall Report |
| Signed calls losing attestation in transit | More than 60% (industry estimate) | FCC Triennial Report |
| Robocall rate, A vs C attestation | 1.6% vs 7.8% (August 2026) | TransNexus |
| Prolific robocall signers using A-level | 71% (August 2026) | TransNexus |
| Scams A-level attested (honeypot) | Over 50% | TNS, via FCC |
| Participating STIR/SHAKEN providers | More than 1,900 | STI-GA 2025 SHAKEN Report |
| Providers authorized in early 2021 | 74 | FCC Triennial Report |
| Providers certifying full implementation | Nearly 3,500 of 9,000+ RMD filers | FCC Triennial Report |
| Providers removed from the RMD, August 2025 | 185 + more than 1,200 | FCC removal orders, via Wiley |
| Providers removed, September 2026 | 14 | FCC Enforcement Bureau |
| SPC token revocations after RMD deletion | 7 (2025) | STI-GA 2025 SHAKEN Report |
| US robocalls, 2025 | 52.5 billion | YouMail Robocall Index |
| FTC Do Not Call complaints, FY2025 | Over 2.6 million | FTC DNC Data Book FY2025 |
| Americans who think scammers are winning | Nearly 2 to 1 vs carriers | Hiya State of the Call 2026 |
| French roaming calls authenticated | More than 80% (end-2025 target) | Arcep |
| Drop in spoofed calls with Indian numbers | 97% | India DoT, via ANI |
Methodology and Sources
Every figure above was read in this session from the organization that produced it or from a named intermediary reporting that organization’s document. Where a regulator’s own page blocked automated access (Ofcom, CRTC, India’s PIB), we used the named trade or legal publication and say so below. Vendor statistics (TransNexus, TNS, YouMail, Hiya) are based on each company’s own traffic or survey sample.
- TransNexus monthly STIR/SHAKEN statistics: August 2026, June 2026, February 2026, August 2025, May 2025; FCC robocall scorecard proposal (September 2026)
- FCC: STIR/SHAKEN Triennial Report (December 19, 2025), Eighth Report and Order, FCC 24-120 (November 2024), Enforcement Bureau removal of 14 companies (September 2026)
- Legal analyses of FCC orders: Wiley on the August 2025 removals, Wiley on the July 2026 RMD FNPRM, Davis Wright Tremaine on FCC 26-32, Herman Whiteaker on the third-party authentication compliance date
- STI-GA: 2025 SHAKEN Report (published February 2026)
- TNS: 2026 Robocall Report
- YouMail Robocall Index: 2025 annual release, August 2026 release (via Cloud Communications)
- FTC: National Do Not Call Registry Data Book FY2025 and press release (December 2025)
- Hiya: State of the Call 2026 press release
- Lingo Telecom settlement: RCR Wireless, August 2024
- France: Arcep, numbering plan decision (December 2, 2025), Next on the Arcep investigation (January 2026)
- UK: Ofcom statement on CLI guidance, Mobile ID World (July 2025), TelecomLead (July 2026)
- India: DoT figures via ANI/Tribune India (July 2025)
- Canada: CommLaw Group on CRTC Decision 2025-343
- Data watch: The FTC complaint series conflicts across documents. The FTC’s FY2025 Data Book reports over 2.6 million DNC complaints and about five million in FY2021, while the FCC triennial report cites FTC complaints falling from 3.4 million to 1.1 million between FY2021 and FY2024, apparently a narrower robocall-only measure; we cite each with its own label. Provider counts differ by definition (TransNexus authorized providers, FCC tokens authorized, STI-GA participating providers), so the 1,485, 1,739, 1,800+ and 1,900+ figures are not one series. The TransNexus 64% unregistered-filer estimate dates from before the September 2025 compliance date. The 84% (FCC) and 85% (TNS) major-carrier signing figures cover 2025 traffic among large providers only. The Arcep 80% figure is a target stated in December 2025, not a measured result. Ofcom, CRTC and India’s PIB pages returned 403 errors to our fetches, so those numbers were read through the publications named above. The Lingo Telecom case is from 2024 and is historical context. TransNexus no longer publishes absolute authorized-provider counts in each monthly report.
Last updated: October 3, 2026. We update this roundup quarterly, and the next refresh is expected when TransNexus publishes its September 2026 STIR/SHAKEN statistics, the STI-GA releases its 2026 SHAKEN Report, and the FCC acts on its KYUP, RMD and robocall scorecard proposals.