Abstract Research on regulation has traditionally focused on studying the delegation of regulatory competencies from political principals to an independent regulatory agency. In this article, we argue that this delegation is nuanced by different factors that affect whether a specific regulatory decision is formally delegated. We examine and explain formal delegation patterns at the level of individual regulatory decisions in twelve countries located in Europe, Latin America, and South Asia. The data were gathered by coding the twelve countries' telecommunications legislation. The data analysis was undertaken using a classification tree model—a nonparametric model. We found that the maturity of the market has the greatest effect on the formal delegation of regulatory decisions, but this effect is also influenced by the other theoretical factors considered, particularly the level of political constraints and the type of regulation.