How Long Does a Merger Take From Announcement to Closing
The timetable depends on antitrust review, the shareholder approval route and foreign regulators. This step table shows how long each stage takes and why deals slip.
A US public-company merger takes anywhere from about two months to well over a year from announcement to closing. A cash tender offer with no antitrust issues can finish in under two months; a large deal that draws a second request or foreign reviews can take a year and a half. The merger agreement’s conditions and outside date set the limits.
Two recent deals show the range. Sanofi signed its agreement to buy Dynavax Technologies on December 23, 2025, and its tender offer expired successfully on February 9, 2026, about seven weeks later. Synopsys signed to buy Ansys on January 15, 2024 and closed on July 17, 2025, about 18 months later, after an FTC review that ended with required divestitures.
What are the steps from announcement to closing?
Most deals move through the same stages. Several run at the same time, so the slowest one decides the closing date.
| Step | Typical length | What sets the clock |
|---|---|---|
| Signing and announcement | Day 0 | Merger agreement filed with an 8-K within four business days |
| HSR filing | Often within a few weeks of signing | Deadline negotiated in the merger agreement |
| HSR initial waiting period | 30 days (15 for a cash tender offer) | Hart-Scott-Rodino Act |
| Second request, if issued | Months, then 30 more days after the parties substantially comply (10 for a cash tender offer) | FTC or DOJ |
| Preliminary proxy filed with the SEC | At least 10 calendar days before the final proxy is mailed | SEC Rule 14a-6; longer if the SEC staff reviews it |
| Shareholder meeting and vote | Weeks after the proxy is mailed | Record date and meeting date set by the board |
| Tender offer instead of a vote | At least 20 business days | SEC Rule 14e-1 |
| CFIUS review, if a foreign buyer | 30-day assessment for a declaration; 45-day review plus a possible 45-day investigation for a notice | Committee on Foreign Investment in the United States |
| EU merger review, if thresholds are met | 25 working days in Phase I; 90 working days in Phase II, with possible extensions | European Commission |
| Closing | Often within a few business days after the last condition is met | Merger agreement |
How does the HSR antitrust review work?
Deals above a size threshold must be reported to the FTC and the Justice Department under the Hart-Scott-Rodino Act, and the parties cannot close until a waiting period ends. As of November 2026, the basic reporting threshold is $133.9 million, in effect since February 17, 2026, with size-of-person tests applying to deals up to $535.5 million (FTC current thresholds).
The initial waiting period is 30 days, or 15 days for a cash tender offer or a bankruptcy sale. The agency can end it early through early termination, or extend it by issuing a second request for documents and data. After the parties substantially comply with a second request, the agency has another 30 days (10 for a cash tender offer) to act. Second-request reviews usually take months. Some end with a settlement requiring divestitures, as in Synopsys and Ansys; others end with the deal cleared or with a lawsuit to block it.
The filing form itself changed twice: an expanded HSR form took effect on February 10, 2025, and a federal court vacated it, with the FTC accepting the older form again from March 2026. Our guide to the HSR filing covers fees and the form.
How long does the shareholder vote take?
A vote adds at least several weeks, because the company must prepare a proxy statement, file it with the SEC and mail it before the meeting. A preliminary merger proxy has to be filed at least 10 calendar days before definitive copies go out, and the SEC staff may review it, which adds time.
Under Delaware law, a merger needs approval by a majority of the outstanding shares entitled to vote, not just a majority of those voting. A deal using a tender offer can skip the meeting entirely if the buyer gets enough shares, which is one reason cash buyers use them. See our explainers on merger votes and proxy statements and how tender offers work.
Which foreign reviews can slow a deal?
Deals involving a foreign buyer or companies with large sales abroad can need approvals outside the HSR process. The common ones:
- CFIUS reviews foreign investments in US businesses for national security. A short declaration gets a 30-day assessment. A full notice gets a 45-day review, a possible 45-day investigation (extendable by 15 days in extraordinary cases), and, if referred, 15 days for the President to decide (CFIUS overview).
- The European Commission has 25 working days for a Phase I review and 90 working days for a Phase II investigation, with extensions of 15 or 20 working days possible. The deal cannot be completed before clearance.
- Other regulators, including those in the UK and China, run their own reviews, and their timing is listed in the proxy’s “Regulatory Approvals” section.
What does “expected to close in” mean, and why do deals slip?
“Expected to close in the second half of 2026” is the companies’ estimate when they sign, not a deadline. The binding date is the outside date (or end date) in the merger agreement, after which either side can usually walk away. Some agreements extend that date automatically if only regulatory approvals are missing.
Deals slip for a few recurring reasons: a second request, a foreign regulator asking for more time, a lawsuit by the FTC or DOJ, financing delays in leveraged buyouts, or a competing bid. Each shows up in an 8-K or a press release, so following the target’s filings is the fastest way to see a new timetable. When the market expects delays, the gap between the stock and the deal price usually widens, as explained in why a stock trades below the deal price.
Bottom line
To estimate your own deal’s timing, find three things in the filings: whether it uses a tender offer or a vote, which regulatory approvals are listed as conditions, and the outside date with any extensions. A cash tender offer with only HSR clearance listed is the fast case; a deal listing CFIUS, the EU and China is the slow one.
FAQ
What is the fastest a public merger can close?
A cash tender offer must stay open at least 20 business days, and HSR review runs alongside it with a 15-day waiting period. Sanofi’s offer for Dynavax expired successfully about seven weeks after the merger agreement was signed.
Can a deal close before the expected date?
Yes, if all conditions are met early, such as when the HSR waiting period is terminated early and the vote or tender offer succeeds. Companies announce early closings in a press release and an 8-K.
What happens when the outside date passes?
Either party can usually terminate the agreement, though some agreements allow extensions for pending regulatory approvals. Termination can trigger a breakup fee if the agreement says so.
Does a second request mean the deal will be blocked?
No. A second request means the agency wants a closer look. Some deals that receive one close, sometimes after agreeing to sell certain businesses or assets.
