As a general matter, disclosing information subject to the attorney-client privilege constitutes an implied waiver of the privilege, meaning that the disclosing party could be compelled to produce that information in future litigation.
But one court, using the theory of “common legal interests,” held that the prospective purchaser and seller of a subsidiary had sufficiently overlapping legal interests to justify a finding that the sharing of a legal opinion did not waive the privilege with respect to that opinion, even though the transaction was never consummated. Hewlett-Packard Co. v. Bausch & Lomb, Inc., 115 F.R.D. 308, 7 Fed. R. Serv. 3d 718 (N.D. Cal. 1987); see also David M. Greenwald, Edward F. Malone & Robert R. Stauffer, 1 Testimonial Privileges § 1:70 (3d ed.) (2010).
But to be able plausibly to invoke a common interest to protect privileged information, the parties should anticipate collaborating in pending or future litigation. That’s more likely to occur in the context of a substantial M&A transaction. See Anne King, The Common Interest Doctrine and Disclosures During Negotiations for Substantial Transactions, 74 U. Chi. L. Rev. 1411 (2007).
If the disclosing party won’t be disclosing information subject to the attorney-client privilege, answer “No” to this question.