Employers concerned about potential unionization percolating in their ranks are racing to beat the union by filing their own organizing petitions with regulators, hoping to gain tactical advantages such as defining the scope of the bargaining unit.

The number of so-called RM petitions for election filed by employers—as opposed to RC petitions filed by workers—rocketed 2,089%, to 416 petitions, between the start of the federal fiscal year last October and the end of July.