Published online by Cambridge University Press: 22 September 2015
European Union (EU) coexistence policy is based on the principle of subsidiarity, which implies a multilevel governance framework. Different legislative approaches have been developed in EU Member States. These legal rules are oriented to both preventing on-farm adventitious admixture (ex-ante regulations) and reducing potential economic consequences (ex-post liability). So coexistence deals with a subject of negative externalities involving an issue of property-right allocation between farmers. Considering the impacts that coexistence policy has on GM (genetically modified) crop adoption rates and the generation of trade distortions, potential effects of the EU coexistence framework are reviewed from a theoretical property-right allocation view. Derived from the analysis, property-right allocation is focused on non-GM farmers according to EU regulation enforcement, which tends to rigid coexistence measures. Nonetheless, the multilevel EU framework has led Member States to pursue their aims: trade interests and social legitimation.