Several low- and middle-income countries are interested in extending their existing health insurance for specific groups to eventually cover their entire populations. For those countries interested in such an extension, it is important to understand what characterises a well performing social health insurance scheme. This article provides a simple framework to analyse key performance issues related to the functions of health financing within the context of social health insurance. The framework first illustrates how performance in the health financing functions of revenue collection, pooling and purchasing affects the realisation of health financing targets of resource generation, optimal resource use and financial accessibility of health services for all. Then, within each health financing function, key performance issues and associated measurable indicators are developed. The set of performance indicators provided in this article should help policy makers to monitor the development of social health insurance schemes and identify areas for improvement. In doing so, policy makers can come closer to achieving universal coverage -- access to appropriate healthcare for all at an affordable cost -- the ultimate goal of social health insurance.