The Law and Economics of Extreme Sports Sponsoring in Comparative Perspective. – This article investigates the law and economics of extreme sports sponsoring in a comparative perspective. It is based on 40 structured interviews with sponsored athletes from various common law and civil law jurisdictions. The article demonstrates that the current contracting practice is unbalanced and inefficient. It entices athletes to take unreasonably high risks. There are ways to significantly increase the cooperative surplus compared to the status quo. The article further demonstrates that sponsor firms face increased and mandatory duties of care towards young and/or inexperienced athletes. In particular, such athletes should not be influenced by bonus systems in their risk-taking behaviour. The duties of care of a sponsor under contract and/or tort law are also determined by the degree of control exercised by a sponsor and the economic dependence of the athlete on the sponsor. This allows creating a finely tuned regulatory system that, unlike the dichotomy of an independent contractor and dependent worker, is better able to do justice to individual cases.