Wal-Mart is trying to halt the lawsuit, with the backing of many other big companies concerned about rules for class-action cases — those in which people with similar interests increase their leverage by joining in a single claim. Class actions against discount seller Costco and the tobacco industry are among pending claims that the high court's decision might alter.
The suit against Wal-Mart Stores Inc. contends that women at Wal-Mart and Sam's Club stores are paid less and promoted less often than men. The case the high court accepted on Monday will not examine whether the claims are true, only whether they can be tried together.
Estimates of the size of the class range from 500,000 to 1.5 million women who work or once worked for Wal-Mart.
Wal-Mart, based in Bentonville, Ark., is appealing a ruling by the 9th U.S. Circuit Court of Appeals in San Francisco that the class-action lawsuit could go to trial.
Tobacco giant Altria Corp., Bank of America Corp., Dole Food Company Inc., General Electric Co., Intel Corp., Pepsico Inc. and United Parcel Service Inc. are among the companies that also called for high court review of the case.
Wal-Mart praised Monday's Supreme Court intervention.
"The current confusion in class action law is harmful for everyone — employers, employees, businesses of all types and sizes, and the civil justice system," Wal-Mart said in a statement. "These are exceedingly important issues that reach far beyond this particular case."
Lawyers representing the women said they are eager to resolve procedural issues that have delayed the trial.
They said they "welcome the U.S. Supreme Court's limited review of the sex discrimination case and are confident that the court will agree that the women of Wal-Mart are entitled to their day in court."
Wal-Mart employs 1.4 million people in the United States and 2.1 million workers in 8,000 stores worldwide. The company said the women should not be allowed to join together in the lawsuit because each outlet operates as an independent business. Wal-Mart argued that it doesn't have a companywide policy of discrimination, and therefore women alleging gender bias should file individual lawsuits against individual stores.
The plaintiffs contend that the company was aware that it lagged behind other employers in terms of opportunities for women and that Wal-Mart imposes uniform rules and tight controls over its stores.
Wal-Mart said that allowing the large number of claims to go forward would set off an avalanche of similar class-action lawsuits in California and the other Western states overseen by the 9th Circuit. Class-actions increase pressure on businesses to settle lawsuits because of the cost of defending them and the potential for very large judgments.
But the lawyers representing the women who are suing Wal-Mart say there have been only eight such suits nationwide — and none within the 9th Circuit — since the first appeals court ruling in favor of the women nearly four years ago. "This threatened landslide of class-action litigation has not materialized," the lawyers said in legal papers filed with the Supreme Court.
Patty Edwards, chief investment officer at Trutina Financial, a wealth investment and management company in Bellevue, Wash., said that if the case is allowed to be pursued as a class-action suit, it could hurt Wal-Mart's image, which she said has greatly improved in recent years. In 2009, Wal-Mart created a women's leadership council made up of senior executives from the more than dozen countries it operates in.
The lawsuit was first filed by six women in federal court in 2001. The 9th Circuit has three times ruled that the case could proceed as a class action.
In its latest decision, in April, the appeals court voted 6-5 in favor of the plaintiffs. Judge Michael Daly Hawkins said that the number of women involved is large, but "mere size does not render a case unmanageable."
Judge Sandra Ikuta's blistering dissent said the female employees failed to present proof of widespread discrimination. Without such evidence, Ikuta said, "there is nothing to bind these purported 1.5 million claims together in a single action."
The case will be argued in the spring.
The case is Wal-Mart Stores v. Dukes, 10-277.