Victory for House Republicans in federal court last week could mean significantly higher health insurance premiums for millions of people if the decision is upheld on appeal, the Obama administration said Monday.

Many insurers have lost money on the Affordable Care Act plans they sell to consumers. A new analysis shows how much those losses deepened in 2015, the second year of the law’s signature exchanges.

A California law that kicks in Monday makes immigrant children without legal documentation eligible for comprehensive, government-paid health care.

This week I answer readers’ questions about buying plans off the insurance marketplaces and more general questions about coverage.

California’s health insurance exchange estimates that its Obamacare premiums may rise 8 percent on average next year, which would end two consecutive years of more modest 4 percent increases.

Federal district Judge Rosemary Collyer, a Republican appointee, ruled that the law does not provide for the funds insurers need to make health insurance policies under the program affordable.