Wal-Mart Stores have argued in the U.S. Supreme Court that the largest class-action sex-discrimination lawsuit in history by female employees, who seek billions of dollars, should be halted. Wal-Mart contends that the suit cannot stand, as hiring practices and anecdotal evidence of discrimination cannot be tied to the company, which has an official policy of non-discrimination which applies across the whole of the organisation.

The six plaintiffs are seeking lost pay and damages. They want the US Supreme Court to allow the case to proceed as a class action lawsuit against the company. A class action suit would cover any woman who has worked for, or works for, one of more than 3,400 Wal-Mart stores since December 1998. Two lower courts have allowed the suit to proceed, but Wal-Mart appealed to the Supreme Court.

Supreme Court justices questioned whether female employees could show that a common discriminatory policy governed the company’s pay and promotion decisions, which echoed Wal-Mart’s argument that the suit could not stand as hiring practices and anecdotal evidence of discrimination cannot be tied to the company, which has an official policy of non-discrimination. The plaintiffs allege that Wal-Mart allowed great discretion to local managers to make pay and personnel decisions and instilled in those managers – “the Wal-Mart way” – that was used to pay women less than men who were doing the same work in the same facilities at the same time and provided fewer opportunities for promotion.

The key issue before the Court is not whether Wal-Mart is guilty of discrimination, but whether the women suing have made a compelling case that a jury should hear the issue. The Court’s ruling is expected in late June and could affect the future of other class-action lawsuits that pool modest individual claims into a single action that creates the potential for a large compensation judgment.