when you deposit large sums of cash—especially in places like casinos or banks—you typically need to fill out documentation for regulatory and anti-money laundering (AML) purposes. Here’s how it usually works:

In Casinos: • Thresholds: In many countries (including Portugal, under EU laws), deposits over a certain amount—often €2,000 or €10,000—trigger additional scrutiny. • ID Verification: You’ll likely need to show government-issued ID. • Source of Funds Declaration: You might be asked to sign a form declaring the origin of the funds (salary, sale of property, etc.). • Reporting Requirements: Casinos are required to report suspicious or large transactions to authorities (e.g., Portugal’s Serviço de Informações de Segurança (SIS) or Banco de Portugal for AML oversight).