The lawsuit — originally filed in 2001 by California Wal-Mart greeter Betty Dukes and five female colleagues — alleges that women employees are paid less and promoted less often than their male counterparts at Wal-Mart stores across the country.

In its 137-page decision on April 26, the 9th Circuit, sitting en banc, ruled 6-5 in favor of certification, rejecting Wal-Mart’s argument that the case was too large to be a class. “[M]ere size does not render a case unmanageable,” Judge Michael Daly Hawkins wrote for the majority.