Regulating private actors' participation in policymaking is key to democratic governance. Across political systems, targeted transparency is used to regulate lobbying activities. We examine the extent to which primary regulatory targets (organizations with frequent access to policymakers) support the architecture of lobbying regulation regimes set up as voluntary transparency clubs. Our empirical testing ground is the European Union. We conceptualize the EU Transparency Register as a Voluntary Transparency Club, elaborate on its club goods, and derive a set of theoretical expectations about its members' evaluations of the club's transparency standards, membership size, and monitoring and enforcement mechanisms. We find significant differences between members and non-members' assessment regarding the regulatory performance of this transparency club. Members with frequent access to executive policymakers criticize the club's transparency standards and do not consider the Register a useful regulatory instrument. Yet, they support expanding its regulatory remit and increasing the club membership.