McKesson HBOC, Inc. v. Superior Court, 115 Cal. App. 4th 1229 (2004)
After McKesson publicly disclosed that its auditors had discovered improperly recorded revenues at a McKesson subsidiary, it became the subject of shareholder lawsuits and investigations by the United States Attorney’s Office and the SEC. McKesson retained an outside law firm to represent it in the shareholder lawsuits and to perform an internal review of the matter. McKesson’s attorneys subsequently disclosed the results of their investigation to the United States Attorney and the SEC after entering into confidentiality agreements with the government, reflecting the attorneys’ belief that the documents were protected by the attorney-client privilege and the work-product doctrine. Meanwhile, in the civil actions that were pending in San Francisco Superior Court, Merrill Lynch asserted that McKesson had waived the privilege and work-product protection by disclosing the documents to the government, since disclosure of the documents to the government was not required in order for the attorneys to provide legal advice to McKesson. The trial court and Court of Appeal agreed with Merrill Lynch and ordered McKesson to produce to Merrill Lynch the documents that McKesson had provided to the government.