An information gap could keep the Affordable Care Act from helping those who really need the law's help.

The Obama administration on Monday offered a surprisingly modest estimate of the number of people who would sign up for health insurance in the second round of open enrollment, which begins on Saturday.

Some large employers will face penalties if they don't offer workers health insurance in 2015.

The Obama administration said Sunday that consumers could shop for health insurance and compare their options on HealthCare.gov starting Monday, even before the open enrollment period formally begins five days later.

The Supreme Court announced Friday that it will hear the most serious challenge to the Affordable Care Act since the justices found it constitutional more than two years ago: a lawsuit targeting the federal subsidies that help millions of Americans buy health insurance.

Covered California, the Obamacare exchange that led the nation during its first year with about 1.2 million enrollees, predicts the tally will jump to 1.7 million in year two - a 500,000 increase, more than many states netted in total last time around.