Turkey VDK KURGAN — AI real-time anomaly detection in e-invoices for tax fraud

Turkey's Tax Audit Board (Vergi Denetim Kurulu, VDK) launched the KURGAN anomaly-detection system on 1 October 2025 as the centrepiece of its Fake Document Combat Strategy. Applying machine learning across 13 evaluation criteria, KURGAN cross-references every e-invoice, e-ledger, and banking transaction in near real time, flagging purchase-sale mismatches, warehouse-capacity discrepancies, and patterns indicative of carousel or missing-trader VAT fraud. Turkey's mandatory e-invoicing infrastructure, spanning millions of VAT-registered businesses and billions of documents annually, provides the data substrate enabling KURGAN's nationwide, real-time cross-referencing.

Rather than issuing automatic penalties, KURGAN sends early-warning letters to flagged taxpayers, giving them the opportunity to correct declarations before formal enforcement — an advisory-first approach intended to raise voluntary compliance alongside detection.

In 2025, VDK's AI-assisted compliance programme identified approximately 748 billion Turkish lira in undeclared taxable income and assessed 294 billion TL in tax penalties, while 86.8 billion TL in additional tax base was voluntarily declared through the invite-to-explain process. Because KURGAN launched on 1 October 2025, full-year 2025 figures reflect a blend of legacy and new-system detection, so attribution of these outcomes to KURGAN specifically remains partial.