The brief focuses on the cost of inaction regarding early childhood development (ECD). It highlights that underinvestment in ECD leads to poor outcomes for children, families, and societies, resulting in inefficiencies and inequalities. The brief underscores the need for countries, especially G20 members, to rebalance their public expenditures and prioritize early childhood policies. Key recommendations include increasing spending on the youngest children, implementing universal child benefits, and integrating gender-responsive policies to address disparities and improve long-term social and economic returns.