The common interest doctrine can allow separately represented clients to avoid the normal privilege waiver implications of sharing privileged communications. But the doctrine is unpredictable and therefore risky.

In Hempel v. Cydan Development, Inc., Case No. PX-18-3404, 2020 U.S. Dist. LEXIS 153208 (D. Md. Aug. 24, 2020), the court rejected plaintiffs' common interest doctrine assertion. The court noted that "[i]n the Fourth Circuit, the proponent of the common interest privilege must produce evidence of an agreement between the individuals with the common legal interest." Id. at *22. Acknowledging that "[w]hile a written agreement is not required, and it is not necessary that 'both parties to the communications at issue be co-parties in litigation,' . . . 'there must be an agreement or a meeting of the minds." Id. Plaintiffs' common interest doctrine argument failed because "[p]laintiffs have not met their burden to demonstrate that the common interest privilege applies because they have not produced evidence of an actual agreement with any third parties" – and "the common interest privilege cannot be found to apply in the absence of an agreement." Id. at *23.

Common interest participants must remember this threshold requirement. About a month earlier, the court in Elvis Presley Enterprises, Inc. v. City of Memphis, No. 2:18-cv-02718, 2020 U.S. Dist. LEXIS 125534, at *24 (W.D. Tenn. July 16, 2020), found the common interest doctrine applicable because "the parties entered into an oral common interest arrangement" – also providing Privilege Points the rare opportunity to rely on a case involving Elvis Presley.