In order to help address climate finance-related information needs under the UNFCCC, this paper explores the extent to which currently-available secondary data make it possible to estimate private finance mobilised by developed countries for climate action in developing countries. This is done by testing the implementation of two approaches: the first one based on an analysis of an investment-related commercial database, and the second one based on the use of publicly-available private finance leverage ratios. Due to data constraints, the focus is on renewable energy as a sub-set of climate mitigation activities.