In 1924, a Portuguese entrepreneur named Artur Alves dos Reis executed a financial forgery so sophisticated that it nearly caused the economic collapse of Portugal. Instead of printing counterfeit banknotes himself, Reis recognized a flaw in the system and decided to outsource the printing to the Bank of Portugal's official printer, Waterlow and Sons in London. Reis forged official contracts bearing fake signatures of Bank of Portugal officials, claiming he was authorized to print notes for an urgent economic development project in the Portuguese colony of Angola.
Believing the paperwork was genuine, Waterlow and Sons printed 200,000 legitimate 500-escudo banknotes featuring the portrait of Vasco da Gama. The notes were printed using the original plates, identical paper, and legitimate serial numbers, making them completely indistinguishable from real money because, technically, they were real money. Reis smuggled the cash into Portugal and used his newfound fortune to establish the Bank of Angola and Metropole.
Through his bank, he invested heavily in Portuguese infrastructure, bought real estate, bought corporate stock, and eventually tried to buy controlling shares in the Bank of Portugal itself to cover up his crime. However, in late 1925, a local journalist grew suspicious of Reis's bank offering low-interest loans without taking deposits and alerted authorities. When the scheme broke, public trust in Portuguese currency shattered, causing runaway inflation and widespread financial panic that contributed directly to the 1926 military coup d'état.