This document lays out economic arguments for investing in the Access to COVID-19 Tools Accelerator (ACT-Accelerator). Framed within an overall context that recognizes the broader human health and societal impacts of the COVID-19 crisis, ACT-Accelerator's Economic Investment Case argues that investment in ACT-Accelerator is the world’s best bet and most viable solution for restarting the global economy. It is intended for governments, multilaterals, civil society, businesses and foundations and all those interested in the work required to change the course of the pandemic. The global deployment of ACT-Accelerator’s comprehensive package of tools will reduce the severity of COVID-19 disease, enabling countries to transition out of the crisis thereby restarting domestic and international economic engines driving our global economy.