Whilst international law has traditionally been dominated by states, non-state actors today have an increasing influence on many spheres of international life. This paper argues that non-state actors, in particular business interest non-governmental organisations (BINGOs), not only participate actively within those inter-governmental regimes which have been created by states, but they are also able to establish their own private regimes on particular issues in which they have an interest. The global regulation of oil pollution liability and compensation is used as an example to show how inter-governmental and private regimes can overlap and interact with one another. Such interplay poses several challenges for the way in which we understand traditional state-centred international law-making. At the same time, private regimes themselves raise their own questions of legitimacy and effectiveness.