Federal prosecutors successfully obtained and reviewed communications between private equity firm KKR & Co. and its counsel at Kirkland & Ellis, marking a significant application of the crime-fraud exception to attorney-client privilege. This ruling demonstrates that courts can compel the review of otherwise privileged materials without notifying the client if there is probable cause to believe the communications were used to further a crime or fraud. The article explains that under the crime-fraud exception, established by US Supreme Court precedent since 1824, lawyers do not need to be complicit in fraudulent conduct for their advice to lose privilege protection. It is sufficient if the lawyer acted merely as an instrument of the fraud, even if unaware of the client's specific objectives. This legal principle applies broadly across federal jurisdictions and impacts both attorney-client privilege and the work product doctrine. In response to this ruling, the piece advises M&A counsel to strictly adhere to antitrust laws, particularly regarding Hart-Scott Rodino filings with the FTC and DOJ. It highlights that omitting competitive harm information or failing to document legal reasoning for disclosure decisions can invite ex-parte applications. Recent ethical rule changes, such as revisions to ABA Model Rule 1.16 in 2023, now mandate lawyer diligence and potential withdrawal if a client seeks to use legal services for fraud. To mitigate these risks, the article urges deal counsel to structure communications carefully to avoid inadvertent privilege waivers, such as including unrelated third parties in sensitive emails. It emphasizes that protecting privilege requires clear protocols during the pre-deal, documentation, and post-closing phases of a transaction. Ultimately, the difference between maintaining privilege and facing exposure often turns on decisions made within the deal room rather than in the courtroom.