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Brian Reissaus

Senior Advisor, National Security*

National security |

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About Brian Reissaus

Brian is a senior advisor in our global foreign investment review and national security practices. Having led the Committee on Foreign Investment in the United States (CFIUS) through its most significant expansion in 30 years, Brian advises companies on CFIUS reviews, other U.S. national security review processes, non-U.S. foreign investment review processes, and U.S. national security policymaking.

He most recently served as Deputy Assistant Secretary for Investment Security Operations at the US Department of Treasury, managing Treasury’s role as chair of CFIUS and leading the development and implementation of US policies regarding inbound and outbound foreign investment. For the first 16 months of the Biden Administration, Brian also served as Acting Assistant Secretary of the Treasury for Investment Security.  

At Treasury, Brian also led the negotiation and implementation of the Foreign Investment Risk Review Modernization Act of 2018 (FIRRMA). 

Prior to joining the Treasury Department, Brian worked at the US Department of Defense as an Action Officer for the Foreign Ownership, Control, or Influence (FOCI) Operations Division at the Defense Security Service where he developed, negotiated, executed and monitored compliance of FOCI mitigation agreements with contractors eligible to hold classified contracts.  

Recent work

Brian’s experience in government includes:

  • Led the Office of Investment Security through two presidential transitions including as the Acting Assistant Secretary for Investment Security from January 2021 through July 2022.
  • Led the drafting of the Foreign Investment Risk Review Modernization Act of 2018 (FIRRMA) and the negotiations with Congress that resulted in its passage.
  • Led the implementation of FIRRMA including the development of FIRRMA’s implementing regulations and the resulting restructuring and expansion of the Office of Investment Security.
  • Managed the processing of over 1500 notices and declarations filed with CFIUS with a combined transaction value of over $1tn.
  • Implemented the FIRRMA Pilot Program and established the CFIUS Declarations process.
  • Developed the CFIUS’s framework to impose penalties for violations to CFIUS mitigation agreements used to impose the first civil monetary penalty imposed by CFIUS.
  • Led the development of the CFIUS case management system, which modernized and significantly improved the efficiency of processing CFIUS filings. 
  • Led the development of CFIUS’s enforcement guidelines and expansion of CFIUS’s monitoring and enforcement efforts.
  • Led U.S. Government efforts to assist international partners and allies establish and implement investment screening regimes including co-chairing the Investment Screening Working Group for the U.S.-E.U. Trade and Technology Council. 



  • Secretary of the Treasury’s Meritorious Service Award, January 2021 and October 2022
  • Recipient of The Treasury Medal for 14 years of service, August 2023


  • National Intelligence University, September 2012 – June 2013
  • The George Washington University, August 2005 – May 2009
    • Elliott School of International Affairs, B.A. (Major: International Affairs; Concentration Middle Eastern Studies)

*Not admitted to the practice of law