Welfare privatisation is generally analysed as welfare state retrenchment or liberalisation: reducing the role of public provision is understood as reducing the role of the state in allocating welfare benefits. This thesis starts from the puzzling observation that pension privatisation seems to go hand in hand with more active state interference in the allocation of private pensions. In order to explain the political dynamics that drive state intervention in the organisation of private welfare, this project moves away from established explanations based on electoral politics and social partner mobilisation. Instead it focuses on the interaction between states as independent actors with a stake in stabilising the welfare system, and financial welfare providers with a commercial interest in public support for private welfare. The first paper examines why Germany and the UK - despite having very different institutional backgrounds - exhibit a surprisingly similar shift away from their voluntarist approach to organising private welfare since the 1990s. This supports the central argument of this thesis. The second paper focuses on explaining one important aspect of recreating social protection within private welfare provision: the ability to organise collective risk-sharing to protect against financial volatility. Whereas prevailing explanations focus on social partner voluntarism, this paper compares Denmark and the Netherlands to argue that analytical attention should shift to how regulatory frameworks are required for overcoming distributional struggles. The third paper explains regulatory interventions that go against financial interests in order to achieve social objectives. Examining efforts in the UK to reduce pension charges, it shows that variation in regulatory decisions does not necessarily reflect differences in pressure by voters or organised interest groups. Instead policy-makers make their own assessment of whether regulatory intervention promotes the expansion of private welfare provision - balancing social stability with commercial viability.