Walmart is the world’s largest retailer. And now it may face the largest sex-discrimination class-action lawsuit in history. The U.S. Supreme Court will soon hear arguments in Wal-Mart v. Dukes. The issue – whether or not the 10-year-old case was properly certified as a nationwide class action suit. What began with complaints from a few women could include more than a million past and present female employees of Walmart.

To find out more Eight Forty-Eight‘s Alison Cuddy spoke to Zev Eigen of Northwestern University Law School. Eigen specializes in labor and employment law. He’s also an assistant professor of management and strategy at the Kellogg School of Management.