Signed by President Obama on March 23, 2010, the Affordable Care Act (ACA) includes provisions to expand health coverage to eligible Americans, control health care costs, and improve the health care delivery system. The ACA closes the Medicare Part D donut hole/coverage gap and expands coverage of preventive services for people with Medicare. The Act also creates state-specific Marketplaces, where individuals can go to purchase health insurance. Generally, those with Medicare should not buy health insurance in the Marketplace.