The auto rental giant Hertz is incorporated in Delaware, has its headquarters in New Jersey and does its biggest volume of business in California. So where is Hertz’s “principal place of business?”

The answer depends on which federal appellate court is asking the question. During the past 51 years, federal courts have used a hodgepodge of tests to determine a corporation’s principal place of business. The U.S. Supreme Court today, for the first time, will consider what is the correct test in Hertz Corp. v. Friend, a case involving Hertz employees who claim the company violated California’s wage-and-hour laws.