In a world where global finance must align with the green transition, this Open Access book challenges established economic thinking. It argues for a shift from individualism to group-focused economic theory and policy, revealing that historical financial accumulation stemmed from collective rather than individual actions. To combat detrimental herd behavior, the book advocates for methodological groupism in economic policies. This shift promises more resilient financial flows, ensuring widespread societal benefits and mitigating harm to the global ecosystem. Through data analysis of capital and labor earnings in the US, UK, France, and Italy, and the introduction of "sustainable earnings trends," the book provides actionable insights applicable from local to international levels, using the Sustainable Development Goals (SDGs) as a guiding framework.