Currently there is a strong trend toward sector-specific regulatory authorities across sectors and countries. However, liberalization has not led to a common European regulatory model. The circumstance that different old and new regulatory authorities exist in parallel not only raises agency problems, but also requires a horizontal coordination among the different authorities and their competences. The regulatory regimes differ in the degree to which regulatory authorities are upwardly accountable to governments, horizontally active alongside or related to courts and regulators, or downwardly responsible for operators and interest groups. Based on Williamson (1996, 2005) as well as on Spiller and Tommasi (2005) we try to develop conceptual foundations about the definition and identification of governance costs in regulatory regimes. Following our theoretical findings we explore the Swiss postal regulatory regime and its institutional framework. Our focus is on the identification of the institutional design and the drivers of governance costs in the specific setting of Switzerland.