Covington & Burling was sued this week by securities regulators asking a federal judge to compel the firm to hand over details of clients whose information was accessed in a 2020 cyber attack.

In the firm’s response Wednesday, Covington and its attorney at Gibson Dunn & Crutcher are continuing to claim attorney client-privilege shields them from having to give the U.S. Securities and Exchange Commission details about the close to 300 public company clients whose information is reported to have been compromised.