The plaintiffs who have accused Jones Day of systemically discriminating against women lawyers have expanded on their arguments against the firm, claiming in a 54-page court filing that the firm is trying to avoid court scrutiny of its black-box compensation structure that has permitted discrimination.

The filing in the last week augments a number of the claims that the plaintiffs – Nilab Rahyar Tolton, Andrea Mazingo, Meredith Williams, Saira Draper, Jaclyn Stahl and Katrina Henderson – made in their third amended complaint, while countering Jones Day's defence.

The parties are continuing to lob arguments at each other ahead of a major court ruling that could decide how much of the case will proceed. The plaintiffs are asking U.S. District Judge Randolph Moss of the District of Columbia to reject Jones Day's motion for partial summary judgment, filed in July, in which the firm asserted that some of the plaintiffs' claims in their $200 million proposed class action should be dismissed outright.