O’Melveny Worldwide


O’Melveny skillfully guides clients involved in cross-border transactions through the complex CFIUS national security review process.

“The CFIUS team is ‘extremely dedicated, very knowledgeable and well connected,’ according to clients.”—Chambers USA 

O’Melveny skillfully guides clients involved in cross-border transactions through the complex CFIUS national security review process.

“The CFIUS team is ‘extremely dedicated, very knowledgeable and well connected,’ according to clients.”—Chambers USA 

Drawing on decades of experience in private practice and in senior government positions, our award-winning lawyers are adept at guiding clients through the national security reviews of transactions by the Committee on Foreign Investment in the United States (CFIUS), the Defense Counterintelligence and Security Agency, and other federal authorities. We pride ourselves on knowing a transaction as well as the client does and in conducting research as thorough as any regulator.

We are frequently called upon as CFIUS counsel in complicated, high-profile matters that require seasoned judgment, not only in navigating a review, but also in managing public perceptions—in Congress, in the press, among critics—that can sometimes decide a transaction’s outcome.

Our team features lawyers whose experience includes high-level positions in the White House, Departments of Commerce and Homeland Security, and the National Security Council, among other agencies.

We conduct due diligence on potential transactions to assess national security risks and advise clients on CFIUS requirements and on the advantages and disadvantages of voluntary disclosure. Our team has secured clearance by CFIUS for dozens of transactions, and true to O’Melveny’s interdisciplinary approach, the CFIUS group is a critical member of any international transactions team.

Analogix Semiconductor

Helped US-based semiconductor manufacturer secure CFIUS clearance for its US$500 million acquisition by China-based Beijing Shanhai Capital Management Co, Ltd.

Buyer Consortium

Worked with a Yunfeng Capital–led buyer consortium to secure CFIUS clearance of its US$400 million plan to take private NASDAQ-listed biopharmaceutical firm Cellular Biomedicine Group, Inc.


Guided space imagery company through CFIUS review of its US$3.6 billion acquisition by Canada-based Macdonald, Dettweiler and Associates Ltd.

DL Chemical

Secured CFIUS clearance for Korean petrochemical company DL Chemical Co. to acquire Kraton Corp. for US$2.5 billion—a rare acquisition of a US-listed company by a Korean buyer.

GS Energy Corporation

Counseled South Korean energy solutions company on CFIUS matters relating to its investment in US-based small modular reactor developer.

HID Global

Guided subsidiary of ASSA ABLOY through CFIUS review in its acquisition of HydrantID, a provider of management and automation services.


Helped South Korean conglomerate secure CFIUS clearance for its high-profile, US$1.1 billion acquisition of a controlling interest in US-based robotics leader Boston Dynamics from SoftBank.


Led CFIUS counseling of IBM in multiple landmark transactions, including the sale of its x86 server business to Lenovo, the sale of its global semiconductor manufacturing business to GLOBALFOUNDRIES, and the sale of select software products to HCL Technologies.

Lucid Motors

Helped Silicon Valley-based electric vehicle company secure CFIUS clearance of more than US$1 billion in investments from the Public Investment Fund of Saudi Arabia.

Mentor Graphics

Assisted electronic design automation software firm secure CFIUS clearance of its US$4.5 billion acquisition by German industrial and technology giant Siemens Industry, Inc.

Mitsui & Co.

Counseled Japanese conglomerate in many of its recent cross-border acquisitions and investments, including CFIUS review of their acquisition of Spaceflight, Inc., a space launch rideshare company.

OMERS Infrastructure

Assisted the infrastructure investment manager of the Ontario Municipal Employees Retirement System in securing CFIUS clearance of the US$800 million sale of portfolio company Airports Worldwide to Vinci Airports, a subsidiary of French concessions and construction company Vinci Group.

“On CFIUS issues, the firm ‘brings deep knowledge, experience and relationships within a volatile and unpredictable political environment.’”

—Client Testimonial, Chambers USA 

“In all my encounters with the CFIUS folks, they have been very professional, knowledgeable and responsive.”

—Client Testimonial, Chambers USA 

“Greta [Nightingale] and David Ribner are both superb lawyers. They have a depth of expertise, range of industry experience, and practicality to their practice that I rely on and value over other firms with whom I have worked. What is unique about them is they ‘do their own work’ rather than rely on a team of associates.”

—Client Testimonial, The Legal 500 US 

Theodore Kassinger “deftly combines legal knowledge, political insight and business reality.”

—Client Testimonial, Chambers USA

“Clients say the team ‘runs the process smoothly’ and ‘takes a holistic view’ when it comes to CFIUS reviews.”

Chambers USA 

Greta Nightingale: Ranked for International Trade: CFIUS Experts

Chambers USA (2021–2023)

David J. Ribner: Ranked for International Trade: CFIUS Experts

Chambers USA (2021–2023)