The paper introduces a new concept in ship registration, the net flag-out ratio (in contrast to the standard flag-out ratio) and examines the potential contribution of metrics of corruption and institutional measures as decisive factors in explaining flag choice. Context-related factors are also controlled and included in the study. The study uses a cross-sectional, multiple regression econometric approach. Focusing on a sample of the 33 largest ship owning countries, we find that institutional factors do not explain the traditional flag-out measure but determine the net flag-out ratio. Our findings indicate a potential effect of institutional performance/environment on ship registration.