Medicare and Medicare Advantage remains a growth segment for health insurers and has become a major focus for growth among large, integrated health systems who see profit potential in serving seniors as a Medicare ACO or as a provider-based Medicare Advantage plan. The recent and parallel trends toward consolidation among health plans, among hospitals, and in hospitals’ purchasing of physician groups has created a new competitive dynamic in many markets, where strong integrated providers can leverage their existing patient base, local brand, and market knowledge to compete in Medicare.