What Is CFIUS Review? How Foreign Deals Get Cleared or Blocked
Foreign buyers of US companies can face a national security review on top of antitrust clearance. What CFIUS covers, how long each stage takes and how Presidents have blocked or reshaped deals.
CFIUS, the Committee on Foreign Investment in the United States, is a Treasury-chaired group of agencies that reviews foreign investments in US businesses and some real estate for national security risks. It can clear a deal, impose conditions or send it to the President, who can block it. A full review takes 45 days, plus a 45-day investigation if needed.
The committee’s authority is section 721 of the Defense Production Act, codified at 50 U.S.C. 4565, with regulations in 31 CFR parts 800 and 802. The details below are checked as of November 2026.
Which transactions does CFIUS review?
CFIUS reviews “covered transactions,” and the statute defines four main kinds:
- Control transactions: any merger, acquisition or takeover by a foreign person that could result in foreign control of a US business, whatever its industry.
- Non-controlling investments in US businesses involved with critical technologies, critical infrastructure, or sensitive personal data of US citizens, if the investor gets access to material nonpublic technical information, a board seat or observer rights, or a role in substantive decisions about those areas.
- Real estate: purchases, leases or concessions of property that is in or part of an air or maritime port, or close to a military installation or other sensitive government facility.
- Changes in rights that would give an existing foreign investor control or one of the rights above, and deals structured to evade review.
Voting members of CFIUS include the Departments of the Treasury, Justice, Homeland Security, Commerce, Defense, State and Energy, the US Trade Representative and the Office of Science and Technology Policy, according to the committee’s overview page.
When is a CFIUS filing mandatory?
Filing with CFIUS is voluntary for most deals, but two categories require at least a short-form declaration under 31 CFR 800.401:
- a foreign person in which a foreign government has a substantial interest acquiring a substantial interest in a US business involved with critical technology, critical infrastructure or sensitive personal data; the statute says a voting interest of less than 10% is never a substantial interest;
- certain covered transactions involving US businesses that produce, design, test, manufacture, fabricate or develop critical technologies.
Parties to other deals file voluntarily to get a “safe harbor”: once CFIUS clears a transaction, it generally cannot reopen it. CFIUS can also review deals that were never filed, which is the risk of closing without a filing.
How long does CFIUS review take?
A short-form declaration gets a 30-day assessment, and a full notice gets a 45-day review that can be followed by a 45-day investigation and a 15-day presidential decision period.
| Stage | Length | Notes |
|---|---|---|
| Declaration assessment | 30 days | Short-form filing; CFIUS may clear the deal, ask for a full notice or take no action |
| Notice review | 45 days | Starts the business day after CFIUS accepts the notice |
| Investigation | 45 days | Can be extended once by 15 days in extraordinary circumstances |
| Presidential decision | 15 days | Only if CFIUS refers the transaction to the President |
| Answers to CFIUS questions | 3 business days | For follow-up requests during a review |
The clock starts only after CFIUS accepts a notice, and pre-filing talks can add weeks before that. Parties can also withdraw a notice and refile it with the committee’s approval, which is how some reviews stretch well beyond the statutory periods.
Formal notices carry filing fees based on transaction value, as of November 2026: none under $500,000, $750 from $500,000, $7,500 from $5 million, $75,000 from $50 million, $150,000 from $250 million and $300,000 for deals of $750 million or more.
What can CFIUS do about a risky deal?
CFIUS can clear the deal, clear it with conditions, or refer it to the President. Conditions usually take the form of a national security agreement or letter of assurance, which might require security officers, limits on access to data or facilities, or the sale of a sensitive unit.
Breaking those agreements is expensive. The committee’s enforcement page lists a $60 million penalty against T-Mobile US in 2024 for violating a national security agreement by failing to prevent unauthorized access to sensitive data and to report some incidents promptly, along with smaller penalties for missed deadlines and misstatements in filings.
When has a President blocked or reshaped a deal?
Presidential orders are rare, but they show where the process can end.
- Broadcom and Qualcomm: on March 12, 2018, the President signed an order prohibiting Broadcom’s proposed takeover of Qualcomm.
- Nippon Steel and U.S. Steel: CFIUS received a voluntary notice on March 14, 2024 and referred the deal to the President on December 23, 2024. On January 3, 2025, President Biden prohibited it.
- The same deal, reversed: on April 7, 2025, President Trump ordered a new CFIUS review, and his June 13, 2025 order amended the January prohibition so the deal could proceed if the parties signed a national security agreement materially consistent with a government draft.
Under the statute, the President’s actions and findings in these orders are not subject to judicial review.
What does CFIUS mean for a deal’s timing and shareholders?
For a foreign buyer of a sensitive business, CFIUS clearance is usually a closing condition in the merger agreement, alongside antitrust approval. The two run in parallel: antitrust filings go to the FTC and DOJ under the Hart-Scott-Rodino Act, while CFIUS looks only at national security. Our guide to how long a merger takes shows how regulatory reviews set the closing date.
CFIUS does not confirm or deny which deals it is reviewing, so shareholders learn about it from the company’s proxy statement, 8-K filings or press releases. In May 2025 Treasury announced a Known Investor Program to speed reviews for frequent filers; as of November 2026 it is still a pilot, and Treasury sought public comment on it in February 2026.
Bottom line
When a foreign buyer agrees to acquire a US company, read the merger agreement’s regulatory section for three items: whether CFIUS clearance is a closing condition, the outside date for closing, and any reverse termination fee the buyer pays if approval fails. Those terms show how much regulatory risk the buyer has accepted.
FAQ
Does CFIUS review every foreign acquisition?
No. It reviews covered transactions, and filing is voluntary unless a mandatory category applies. Many foreign acquisitions of businesses without sensitive technology, infrastructure or data never go to CFIUS.
Is CFIUS review the same as antitrust review?
No. Antitrust review by the FTC or DOJ asks whether a deal harms competition. CFIUS asks only whether it threatens national security, and it applies to foreign buyers.
Can a company challenge a CFIUS block in court?
The President’s decision to prohibit a deal and the related findings cannot be reviewed by courts under the statute. Other civil actions challenging CFIUS actions can be brought only in the US Court of Appeals for the District of Columbia Circuit.
