This research examines the impact of Environmental, Social, and Governance (ESG) disclosures on corporate financial performance, specifically focusing on earnings. The study distinguishes between mandatory and voluntary ESG reporting and analyzes their respective influences on earnings quality, persistence, and market valuations. Through extensive analysis of secondary data from global corporations spanning 2015-2024 and primary data from industry surveys, the research identifies significant relationships between comprehensive ESG disclosure practices and improved earnings metrics. The findings reveal that while mandatory disclosures establish minimum compliance standards, voluntary disclosures yield additional financial benefits through enhanced stakeholder trust and reduced information asymmetry. The paper contributes to the growing literature on sustainability reporting by quantifying the financial implications of different ESG disclosure approaches and providing empirical evidence for the business case of strategic ESG integration.