The National Bank of Belgium (NBB) estimates that the “unobserved” economy – illegal economy and undeclared work – accounts for 3.9% of GDP.
In this estimate, which the NBB advises reading with caution, undeclared work makes up 3.4% of GDP, while illegal activities such as drug trafficking, prostitution and smuggling constitutes 0.5%.
The calculation for the illegal economy is partly based on estimates of the economic impact of drug consumption, which has significantly increased in Belgium in the last two decades.
Between 2004 and 2023, expenditure on drugs grew from some €350 million to €1.2 billion (in constant figures, adjusted for more than 60% inflation).
Since 2018 however, the economic impact of drugs has stabilised. Despite the surge in cocaine seizures, the NBB notes no “significant increase or decrease”.
