Sharing privileged communications with someone outside the attorney-client relationship can waive the privilege. Determining whether a waiver has occurred depends, among other things, on the role that the third party is playing.
The court in Strougo v. BEA Associates., 199 F.R.D. 515, 522 (S.D.N.Y. 2001) recently offered this succinct example:
[D]isclosure to an outside accountant whose expertise is crucial to the lawyer’s assessment of his client’s case would not waive the privilege, while disclosure to the client’s accountant who was not involved in the litigation would waive the privilege.
Lawyers deciding whether to share information beyond their immediate client must carefully assess the role of the third party receiving the information. A misstep can waive the attorney-client privilege.