This chapter examines the emergence of self-regulation in European crowdfunding markets through a comparative analysis of codes of conduct (CoCs) adopted by national and transnational industry associations. Drawing on economic theories of self-regulation, it develops a framework distinguishing between ‘coerced’ and ‘voluntary’ self-regulation, with the latter further divided into ‘club-like institutions’ and ‘reputation commons’. The institutional design of most CoCs supports the ‘reputation commons’ theory, evidenced by inclusive membership and weak enforcement mechanisms aimed at preserving collective reputation. A minority of CoCs—notably the Estonian example—exhibit club-like features. The content of CoC provisions also reveals perceived sources of market failure from the platforms’ perspective.