Most courts apply the common interest doctrine only in litigation-related circumstances, although a few courts extend the doctrine to transactional contexts.

In BlackRock Balanced Capital Portfolio (Fi) v. Deutsche Bank National Trust Co., Judge Netburn could not have been any clearer: "[t]he common interest doctrine only shields communications between codefendants, coplaintiffs, or persons who reasonably anticipate that they will become colitigants." No. 14-CV-09367 (JMF) (SN), 2018 U.S. Dist. LEXIS 124631, at *23 (S.D.N.Y. July 23, 2018). Two days later, the court in Heartland Consumer Products LLC v. DineEquity, Inc., No. 1:17-cv-01035-SEB-TAB, 2018 U.S. Dist. LEXIS 124654 (S.D. Ind. July 25, 2018), took a broader view. The court applied the common interest doctrine to communications between two companies that "were together in negotiations with [a third company], and [that] sought and received legal advice about the legal ramifications of aspects of that deal." Id. at *18. Because "the issues addressed in the communications were specific legal issues,” they “do not lose their legal characteristics merely because they arise in the context of a business transaction." Id. at *19.

Companies and their lawyers hoping to maximize privilege protection should welcome these occasional decisions applying the common interest doctrine in transactional rather than just litigation contexts. But they are rare, and companies may not know whether they will be lucky enough to find themselves litigating in those few oases of an expansive common interest doctrine.