STIR — Poland's AI system for real-time VAT carousel-fraud detection

STIR (System Teleinformatyczny Izby Rozliczeniowej) was enacted by law in 2017 and operationalised under Poland's National Revenue Administration (KAS) from April 2018. Built and operated by the National Clearing House (KIR), it mandates all Polish banks to transmit daily transaction data to a centralised platform. Machine learning algorithms assign a risk coefficient to each taxpaying entity; suspicious-entity reports are reviewed by KAS and can trigger bank account freezes — without prior notice to the account holder — for up to 3 months.

By 2019 STIR was analysing over 11 million transactions daily, covering nearly 4 million entities and 5.5 million associated individuals. In 2019, 537 accounts across 113 entities were frozen; blocked assets exceeded PLN 67 million (≈€15 million); KAS estimated STIR-attributable state savings at PLN 584 million (≈€133 million). The broader VAT reform package — STIR plus the split-payment mechanism and mandatory e-invoicing (KSeF) — reduced Poland's overall VAT gap from an estimated €6.6 billion in 2017 to €1.7 billion in 2021 per CASE think-tank data, though the post-2021 gap has partially widened again.

Governance and transparency concerns are significant and independently documented. The scoring algorithm is classified ('the cook does not reveal the secrets of his recipes'). Through 2019, 52 administrative complaints were filed at Warsaw courts; 41 (79 %) were dismissed. A June 2020 Poznań court ruling found that insufficient justification for initial 72-hour blocks invalidated subsequent extensions — the first significant judicial pushback. From July 2019, banks are required to share IP-address data for all account-holders, introduced without public consultation and criticised by the Polish Commissioner for Human Rights and the Panoptykon NGO. AlgorithmWatch classified STIR as a cautionary case of opaque algorithmic enforcement in its Automating Society Report 2020.

Read the full analysis: https://algorithmwatch.org/en/poland-stir-vat-fraud/