The Obama administration has introduced a new rule that will provide overtime pay to millions of currently ineligible workers as of Dec. 1.

The regulations allow full-time salaried employees to earn overtime if they make up to $47,476 a year, more than double the current annual threshold of $23,660. The U.S. Labor Department estimates the rule will boost the pay of an additional 4.2 million workers.

Small business owners were quick to criticize the change, and executives of nonprofit groups and universities say they may have to switch some salaried workers to hourly positions or assign some salaried workers to fewer hours to cut costs.

Labor groups said the change was long overdue. Many people putting in 50 to 60 hours a week without overtime are actually earning less than the minimum wage when all of their hours are taken into account, advocates said.

“The current level isn’t even enough to keep a family of four out of poverty,” said Judy Conti of the nonprofit National Employment Law Project. “It is not at all reflective of somebody who is an executive or a professional.”