This article examines the politics of calculative devices in one of the most successful areas of finance, the life insurance business. By empirically tracing an insurance applicant's risk trajectory, it analyses how calculative devices perform insurance underwriting through acting on insurance risk decisions. This allows one to document what calculative devices exactly do, and to point out the political effects of what they do. First, it highlights the fact that, contrary to thinking in terms of ‘the insurance logic’, there are multiple ways of calcuting life insurance risks. Second, it underscores the crucial role of calculative devices in that process by demonstrating how they align considerations as divergent as economics and medicine to perform a life insurance market. It then demonstrates the political effects of these calculative devices by making explicit how the latter contribute to the production of inequalities in calculative power in life insurance. In this way, the article links up insights from the performativity approach in the sociology of markets with the broader question of governing economic life. Such an approach, it is argued, provides the opportunity to open up the organization of economic markets and to put classic questions of justice and power struggles in economic markets on the agenda again.