As many as 1.5 million women that worked at Wal-Mart stores across the country could be receiving compensation now that an appellate court has ruled that a massive class action lawsuit against the company can go to court.

The decision means that the world’s largest private employer could be forced to pay billions of dollars to women who say they were paid less than men in comparable positions and got fewer promotions.

The massive lawsuit is the result of six women in San Francisco, California that sued the giant in 2001 claiming they were discriminated against based on their gender.

The district court ruled in their favor saying that their suit could cover “all women employed by Wal-Mart at any time after Dec. 26, 1998” including all positions at the company’s 3,400 stores.

Wal-Mart has fought vehemently to appeal those claims since then, arguing that women claiming gender bias should file lawsuits individually against specific stores.

An appellate court made the decision Monday to uphold the district court’s ruling, but asked the trial court judge to consider the size of the lawsuit before ordering the company to pay punitive damages.