This policy brief was produced by the OECD and the European Commission. This policy brief focuses on the informal self-employed and informal entrepreneurs, which together comprise what we define as “informal entrepreneurship”. The policy brief provides estimates of the size of the informal economy and informal entrepreneurship in the EU, investigates its main causes and impacts on the economy, and finally presents a policy framework for formalisation strategies based on the distinction between deterrence, incentives and persuasion measures.