The 2015 Addis Ababa “Billions to Trillions” initiative called for stepped-up private sector investments and financial flows in developing countries. But instead of closing, the “trillion” dollar gap between development and climate needs, and the actual flows continues to widen. Was it a fairy tale? What is certain is that the current operating model of the aid agencies and the development finance institutions, is not helping to crowd-in private flows at the necessary scale. The paper reviews the evidence and highlights what needs to change and how to do it.