1. The documented fact
A national tax filing deadline is one of the very few dates that applies, publicly and identically, to nearly every adult in a country at once. That predictability is exactly what makes tax season the single most reliable moment on the scam calendar — and every major tax authority in the English-speaking world documents it independently, in its own language, with its own numbers.
2. Across four more national tax authorities
Canada
The Canada Revenue Agency proactively revoked over 50,000 user IDs and passwords in 2025 after identifying them as compromised. Separately, the Canadian Anti-Fraud Centre tracked more than $704 million in total fraud losses reported by Canadians in 2025 — a figure the Centre itself says understates the real total, since most fraud goes unreported.
Canada.ca, CRA newsroom; Canadian Anti-Fraud Centre. 🟡 relayed, primary CRA page fetch blocked in this pass.Australia
The ATO recorded 1,386 impersonation-scam reports in May 2026 alone — an 11% increase on April — with fake "outstanding DocuSign" and "recalculated income" emails among the most common lures during 2026 tax time.
ATO Scamwatch data, official. 🟡 relayed via national press, primary ato.gov.au page not directly fetched in this pass.Nigeria
Nearly 60% of Nigerian internet users say they have encountered some form of online scam, according to the Nigerian Communications Commission — out of a base of more than 122 million internet users nationwide, one of the largest online populations in Africa.
Nigerian Communications Commission (NCC). 🟡 relayed, primary ncc.gov.ng page unreachable in this pass (server error).United States
The IRS's public warning explicitly names AI-generated voice calls, fake QR codes on printed letters, and social-media impersonation among the year's dangerous new tactics — over 600 social-media impersonator accounts were reported to the agency in fiscal year 2025 alone.
IRS.gov, official newsroom. Accessed 20/07/2026.3. Religious and cultural calendars
Tax deadlines aren't the only shared, predictable date scammers exploit. Religious and cultural calendars work the same way — a specific week when a specific community is, in large and predictable numbers, doing a specific thing (donating, shopping, celebrating). As always on this site: faith and culture are never the subject here — the people targeted are the victims, and the scammer's arithmetic is identical regardless of which calendar they exploit.
Ramadan charity fraud (UK)
An estimated 3.9 million British Muslims observe Ramadan, a period of markedly increased charitable giving. UK regulators issue an annual joint warning about fake appeal websites, emails impersonating real charities, and pressure callers insisting on an immediate donation — sometimes falsely claiming "you gave last Ramadan too" to lower resistance.
GOV.UK, joint regulator press release. Accessed 20/07/2026.Diwali shopping fraud (South Asian diaspora, UK/US/CAN/AUS)
One in three Indian online shoppers reported falling victim to a festive-season scam in 2025, with fake celebrity endorsements, spoofed "delivery update" texts, and OTP-theft schemes among the most common tactics — a pattern that follows South Asian diaspora communities' own Diwali shopping activity in the UK, US, Canada, and Australia, even though country-specific diaspora loss figures aren't separately published by any regulator we could source.
McAfee, 2025 Festive Season Research. 🟡 India-based consumer survey by a private security vendor, not a government source — cited as context, not as a diaspora-specific statistic.4. The probability
Our calculation — a shared deadline, not a shared target
The principle: the filing deadline is public knowledge, and it's the same for nearly every taxpayer in a given country. A fake "tax refund" or "overdue payment" text sent to a random number is statistically likely to reach someone actively thinking about their taxes that exact week — no personal information required.
What the scammer exploits: there's usually only one national tax authority per country. Impersonating "the IRS," "HMRC," "the CRA," or "the ATO" requires zero research to guess correctly — unlike impersonating one bank among dozens.
Limits: we don't publish a single cross-country probability figure — each authority above measures its own numbers differently, and they aren't directly comparable as one statistic.
5. The mechanism
This scenario runs on Borrowed Authority (there's only one tax agency to impersonate correctly) and Manufactured Urgency (an "overdue payment" or "compromised refund" that demands action before you can verify).
6. The defense
📮Real tax authorities contact you by mail first
Every agency cited above states the same rule: they do not open contact with an urgent phone call, text, or social media message demanding immediate payment.
🔗Go directly to the official site yourself
Never click a link in a tax-related text or email — open your tax authority's official website directly and log in there.
🛡️No threat of arrest by voicemail
A prerecorded voicemail threatening immediate legal action or arrest is, by every agency's own admission, never how they actually operate.
The takeaway
Scammers don't need to know you. The statistics already do.
Frequently asked questions
Why does every tax authority in the world warn about scams at the same time each year?
Because the filing deadline is public and identical for nearly every taxpayer — a fake refund or overdue-payment message lands, by probability alone, on people actively thinking about their taxes that week.
How do scammers know which tax agency to impersonate?
There's usually only one national tax authority per country, so the guess is trivially correct every time.
What will a real tax authority never do?
Leave threatening voicemails demanding immediate payment, or ask for financial details by text or social media message.
Are religious and cultural calendars exploited the same way?
Yes — a period of predictably increased activity within a large community (Ramadan giving, Diwali shopping) creates the same statistical opportunity as a tax deadline. Faith and culture are never the cause; the shared, predictable timing is what a scammer exploits, and the people targeted are the victims.
Rigor note. The UK (HMRC/GOV.UK, and separately the joint regulator Ramadan warning) and US (IRS.gov) figures are confirmed by direct primary citation. The Canada (CRA/Canadian Anti-Fraud Centre), Australia (ATO), and Nigeria (NCC) figures are corroborated across national press and official-adjacent sources but their primary government pages either blocked automated access or returned a server error during this research pass — marked 🟡 accordingly, per our methodology. The Diwali figure comes from a private security vendor's consumer survey in India, not a government source, and is presented as context for diaspora shopping patterns rather than a diaspora-specific statistic — no such figure could be sourced for the UK, US, Canadian, or Australian South Asian communities specifically. This is the first demonstration in this pillar to include an African market (Nigeria) alongside the US/UK/Australia/Canada core — added because the NCC's own scam-prevalence figure is directly comparable in kind to the other four, not because a figure was forced to fit. This page adapts — not translates — the French original (Le calendrier des arnaques); tax season and the two religious/cultural calendars above were chosen as the angles with the strongest available multi-country sourcing.
Fake recruiters
The same "only one legitimate name to impersonate" logic, applied to LinkedIn and the job market.
Learn more
Egidio — The Threat Laboratory, "The scam calendar: tax season, Ramadan, and Diwali scams", egidio.app/en/laboratoire/mathematics-of-manipulation/the-scam-calendar/. Licensed CC BY 4.0.
Free to reuse, including commercially, with attribution. Reuse terms.