The biggest names in health insurance like UnitedHealth Group (UNH), Humana (HUM), Cigna (CI), Wellpoint (WLP) and Aetna (AET) and Blue Cross and Blue Shield plans across the country are contracting with ACOs.

FORBES: Why Donald Berwick's A Hero And Sarah Palin's A Zero

The move comes as major health insurance companies like UnitedHealth Group (UNH), Aetna (AET), Cigna (CI) and Humana (HUM) increasingly profile doctors and link physician pay to performance.

FORBES: AMA CEO Wants To Change Medical Education, Push Quality

In addition, most private health insurance companies, too, such as those operated by Aetna (AET), Cigna (CI), Humana (HUM) and UnitedHealth Group (UNH) as well as Blue Cross plans linking with ACOS to care for more patients.

FORBES: Connect