Eighty-three law firms, including many across the Am Law 100, signed onto an amicus brief this week in an effort to influence the outcome of Covington & Burling’s dispute with regulators over a subpoena seeking the identities of nearly 300 clients accessed during a 2020 cyberattack.

The D.C. powerhouse’s resistance to the U.S. Securities and Exchange Commission’s subpoena has garnered widespread advocacy from a range of fellow firms with a significant presence in the nation’s capital and a shared interest in a case that will likely impact the standards by which lawyers have to divulge sensitive information about clients. The list of industry heavyweights signing on includes Cravath, Swaine & Moore, Kirkland & Ellis and Latham & Watkins.