This article tests functional and institutional explanations for the different levels of formal independence of regulatory agencies in Latin America. The analysis is grounded in an original database of the formal independence level of 104 regulators in 8 countries and 13 regulatory sectors. The results challenge a central claim of the credible commitment hypothesis as they indicate that privatization is not a significant determinant of agency independence nor are utility regulators more likely to be independent than other economic regulators. Veto players are positively correlated with formal independence, indicating that in developing countries they operate together as credibility-enhancing mechanisms, rather than as functional equivalents, as previous studies on developed countries have shown. Democratization is positively correlated with formal independence, whereas trade opening and vulnerability to international pressures has no significant impact. Hence, this article enhances the understanding of the delegation of regulatory powers to formally independent agencies in developing countries.