Hot potato endgame.

Other stakeholders and events will influence whether health insurers' current postmerger prosperity will lead to U.S. health benefit programs that are predominantly sponsored by the private or public sectors. Large employers are encouraging three complementary health benefit innovations to improve the affordability and quality, or "efficiency," of clinical services: portable spending accounts, provider pay-for-performance, and tiered plans. If health insurers prefer private-sector health benefit sponsorship, they will need to implement these innovations robustly, despite the risks they pose to insurers' current but predictably temporary prosperity. Clinical efficiency gains can also sustain access to biomedical innovations for low- and moderate-income Americans.