Sixth Circuit Protects Internal Investigation Materials from Disclosure in Civil Suit

In August 2025, we discussed a Sixth Circuit opinion granting a stay of the District Court’s order to produce documents related to two internal investigations while the Sixth Circuit determined the defendant’s mandamus petition. On October 3, 2025, the Sixth Circuit granted that mandamus petition and vacated the District Court’s order, determining the lower court had committed clear error by adopting a special master’s decision ordering the production of materials that were clearly protected. As with the Sixth Circuit’s August 2025 opinion, this latest opinion reaffirms longstanding legal principles and provides important guidance on the scope of attorney-client and work product protections, especially in the context of internal investigations. We summarize those lessons below. 

As we previously discussed, FirstEnergy Corporation (“FirstEnergy”) had launched two internal investigations following its implication in a bribery scheme and subsequent involvement in multiple civil suits. In assessing whether to grant a stay of proceedings while it ruled on the mandamus petition, the Sixth Circuit rejected the District Court’s reasoning and emphasized the longstanding protections of the attorney-client privilege under Upjohn and work product doctrine.

In its finding that the District Court’s order for the production of investigative materials committed clear error, the Sixth Circuit stated that the District Court “departed from ‘strong and longstanding’ privilege and work-product doctrines.” The Court explained:

[T]here is ‘no way to affirm the District Court’s ruling without abandoning’ nearly a half century (since Upjohn) ‘of jurisprudence concerning the scope of the attorney-client privilege’ and work-product doctrine, or without discouraging ‘full and frank communication’ between companies and their attorneys when investigating their own wrongdoing. Because ‘predictable and certain’ privileged and work-product standards are essential for FirstEnergy and future litigants facing perilous litigation consequences, mandamus relief is eminently appropriate here.

The Court reaffirmed its previous opinion that the use of legal advice for business purposes — whether that be to placate the auditor, to make employment decisions, or something else — does not change the protections afforded that advice. The Sixth Circuit explained that the assessment must be based on how that information was developed, finding that the law firms that conducted the investigation had “determined what happened, whether it was lawful, and what civil and criminal liability could result.” The Court found this clearly constituted legal advice.

Moreover, the Court upheld the work product protection for the sought-after materials. With multiple civil litigations and government investigations, the Court found that the driving force behind the creation of work product in the investigation was actual legal and regulatory threats.

The Court also rejected arguments of waiver, given the company’s limited disclosure of facts in a deferred prosecution agreement, during civil litigation, and with its independent auditor. Because those disclosures were limited to facts that were not privileged, none of those disclosures constituted a waiver. Further, for the disclosures to the auditor, those would have been protected as work product, given the auditor’s independent, non-adversarial relationship with FirstEnergy.

The plaintiffs are now seeking clarification of the Sixth Circuit opinion, filing a motion on October 8, 2025, contending that that defendants’ claim of privilege over facts that witnesses may have learned from the attorneys involved in the investigations is improper. Plaintiffs are arguing that the attorney-client privilege does not cover facts conveyed by an attorney to his client when those facts were acquired from other sources. It remains to be seen how the Sixth Circuit will respond to plaintiffs’ latest arguments.

For now, the Sixth Circuit’s opinion is a resounding endorsement of the protections afforded by the attorney-client privilege and work product doctrine for work performed during internal investigations. Practitioners should take note of these fundamental takeaways to ensure those protections apply to their investigations:

1. Investigations should be conducted by counsel, with counsel hiring third-party expert firms, such as forensic accountants and fraud examiners.
2. Counsel should draft a clear investigation plan identifying the legal impetus for the investigation, including that the investigation is being performed due to anticipated legal and/or regulatory threats and the intent that it will be protected by both the attorney-client privilege and the work product doctrine.
3. Counsel should give Upjohn warnings at the start of witness interviews and document in their notes that those warnings were provided.
4. Counsel should carefully determine how and to whom any findings, such as those contained in a final report (whether written or oral), will be communicated to protect against potential waiver.
5. Counsel should ensure that summaries provided to the government in settlement negotiations and/or materials provided to third parties — such as the independent auditor — do not contain privileged content and instead focus on the underlying facts (as opposed to any legal conclusions). 

If you have questions about internal investigations or related topics, please contact the authors of this article or your Foley & Lardner attorney.