The burden of collecting data and reporting on quality measures is a strain on both providers and payers, exacerbated by the multitude of required metrics and disparate data systems. Covered California, the California health benefits exchange that supports more than 1.9 million Californians receiving insurance through the Affordable Care Act, and insurance carrier Health Net, serving approximately 138,000 members on the exchange, implemented a novel approach to data exchange using Covered California's all-payer claims database (APCD). This initiative used historical cancer screening data for Health Net enrollees who had been insured under different Covered California plans in the prior 5 years and analyzed the impact of historical data sharing on screening rates, cost, and efficiency. Historical data exchange led to improved accuracy of quality measure reporting by up to 14% in breast cancer screening quality scores. Additionally, through reduced administrative costs and the elimination of duplicative testing, Health Net saw more than 40,000 in estimated potential cost savings. The success of the pilot between Covered California and Health Net has led to an expansion across all carriers, highlighting the potential of APCDs to facilitate more targeted quality improvement strategies and improve efficiency in health care. This initiative underscores the importance of innovative data exchange strategies to advance health care quality, efficiency, and equity.