Business groups and state governments are seeking to halt the implementation of a new overtime rule announced earlier this year by the Obama administration.

The rule, which is scheduled to take effect on Dec. 1, will significantly raise salary threshold at which employees can be exempt from mandatory overtime pay when they work more than 40 hours in a week. The threshold will go up from $23,600 a year to $47,476, extending overtime to more than 4 million workers who were previously exempt, according to an estimate by the U.S. Department of Labor.

Twenty-one Republican-run states are suing over the rule change. They levy a number of objections against the rule change, including a provision that will lift the threshold every three years based on inflation, as well as the sheer size of the increase.