M&A Deals Requiring HSR Filings May Also Require Notice to the Department of War

In February 2026, the Department of War (DoW) issued new guidance implementing the requirements in Section 857 of the National Defense Authorization Act (NDAA) for Fiscal Year 2024, requiring companies that submit Hart-Scott-Rodino (HSR) pre-merger notifications to also contemporaneously submit such notices to the DoW, if the transaction meets specified criteria. Both buyers and sellers involved in HSR-reportable deals must be aware of this new filing obligation and assess whether it applies to a given transaction based on the DoW’s stated criteria.

Background of HSR Filings and the NDAA FY 2024

Most sophisticated dealmakers are familiar with HSR filings. When a transaction exceeds certain size thresholds, the parties must notify the Federal Trade Commission (FTC) and the Department of Justice (DOJ) and observe a waiting period before closing. Section 857 of the NDAA FY 2024 included an additional notification obligation during the requisite waiting period to the Department of Defense (now known as the DoW). Until last month, the DoW had not dictated the criteria for reportable transactions or the procedures for notification. Rather than issue guidance through a traditional rulemaking process, the DoW published on its website criteria for reporting transactions to the DoW, thus giving life to a previously dormant obligation.

Criteria for Reporting Transactions to the DoW

The DoW issued the following non-exhaustive list of M&A transactions that may require DoW review:

1. Defense Directed Business: Either party currently, has a history of, or intends to contract with the DoW or perform as a subcontractor on a DoW contract. Notably, this criteria appears to apply if either the buyer or seller is a DoW contractor at any tier.
2. Critical Technologies: The M&A transaction involves one of the six critical technologies vital to U.S. national security.^[1]
   • Applied Artificial Intelligence
   • Biomanufacturing
   • Contested Logistics Technologies
   • Quantum and Battlefield Information Dominance
   • Scaled Hypersonics
   • Scaled Directed Energy
3. Defense Industrial Base Sector: The M&A transaction involves aspects of the Department of Homeland Security’s Defense Industrial Base critical infrastructure sector.^[2]
4. Intellectual Property: One or more of the parties have patents, trademarks, copyright protections, or trade secrets in the above critical technologies or critical infrastructure.^[3] Again, this requirement appears to apply to both parties to the transaction and not just the target company.

If the parties to an M&A transaction are uncertain as to whether the transaction meets the above-stated criteria, they are supposed to contact the DoW M&A Division at [email protected].

Procedure for Notifying the DoW

If the parties to the M&A transaction determine that the transaction meets one of the above-stated criteria and the transaction requires an HSR filing, the parties must email the DoW M&A Division at [email protected].

The email must include:

1. Notice that the party is contemplating engaging in an M&A transaction that may require a premerger review; and
2. Confirm whether the party submitted the Notification and Report form to the Department of Justice and/or Federal Trade Commission.

The DoW has committed to responding to such emails within one (1) business day with instructions for securely submitting the Notification and Report form and additional materials to the DoW.^[4] The reference to “additional materials” may mean that the parties need to provide information to the DoW above and beyond that otherwise mandated for the HSR pre-merger notification.

Practical Guidance for Dealmakers

Start the DoW analysis early.

DoW notification should be part of your initial deal assessment once the parties have determined that the transaction requires an HSR pre-merger notification. If there is any question whether your transaction meets the DoW’s stated criteria, reach out to the DoW early on in the deal process for clarification and guidance.

The IP trigger requires a patent and trade secret audit.

Because the IP trigger can apply even if the parties do not have a history of contracting with the DoW at any tier, parties to the transaction and their counsel should conduct an early-stage review of IP holdings against the six critical technology categories to assess whether a notification to the DoW may be required.

When in Doubt, Ask.

The DoW’s policy provides a means for parties who are unsure whether their transaction meets the criteria to contact the DoW M&A Division directly. When in doubt, the parties to a transaction should submit a request for guidance to the DoW, in particular given the DoW has indicated that the provided list of criteria for notification are “non-exhaustive”. The cost of a preliminary inquiry is trivial compared to the cost of a missed notification obligation.

Update standard diligence questionnaires.

Given these new notification requirements, questions assessing whether the transaction triggers the criteria above for notification to the DoW during the HSR review period should now be incorporated in standard preliminary buy-side and sell-side due diligence questions. 

Be Prepared to Engage with the DoW.

Given the DoW indicated it may request “additional documentation” in addition to the HSR Notification and Report form, parties should be prepared to engage with the DoW and timely provide responsive documentation to prevent delays in the HSR review process.

To discuss whether a transaction meets these new DoW M&A notification requirements or for assistance with complying with these new DoW notification requirements, contact Erin L. Toomey ([email protected]) or Louis Lehot ([email protected]).