The post-COVID stage represents a unique window of opportunity to accelerate the transition towards sustainable development. Public investment will be essential to achieve such a goal; yet, government spending in middle- and low-income countries will address the myriad social demands arising from the current situation. Consequently, reinventing the incentive structure to catalyse efforts in mobilising private finance will remain more crucial than ever. The G20 should bring the debate to the next level and deliver a global public good: an internationally recognised standard for environmental, social and governance investment, key in allowing more effectively integrated approaches to public and private finance.