Most employers won't face a fine next year if they fail to offer workers health insurance, the Obama administration said Monday, in the latest big delay of the health-law rollout.

The Treasury Department, in regulations outlining the Affordable Care Act, said employers with 50 to 99 full-time workers won't have to comply with the law's requirement to provide insurance or pay a fee until 2016. Companies with more workers could avoid some penalties in 2015 if they showed they were offering coverage to at least 70% of full-time workers.

The move came after employers pressured the Obama administration to peel back the law's insurance requirements. Some firms had trimmed workers' hours to below 30 hours a week to avoid paying a penalty if they didn't offer insurance.

A senior administration official said the shift was a response to businesses' concerns, though the official said no one reason was behind the change.

Under the original 2010 health law, employers with the equivalent of at least 50 full-time workers had to offer coverage or pay a penalty starting at $2,000 a worker beginning in 2014. Last year, the administration delayed the requirement for the first time by moving it to 2015.