The HSR waiting period is the 30-day pause (15 days for a cash tender offer or certain bankruptcy sales) that a reportable US deal must sit through after the parties file with the FTC and the Justice Department, and nothing can close until it expires or is ended early. For anyone holding a target's stock, it is the first hard date on the merger calendar. The things that stretch it, from a pull-and-refile to a Second Request, decide whether a deal closes on the original schedule or months later.
Most merger coverage treats Hart-Scott-Rodino as a box that gets ticked. The 2026 filings below show why the HSR calendar is where deal timelines are actually set.
The basic clock: 30 days, ending at 11:59 p.m.
The FTC's own summary is blunt: once the filing is complete, "the parties must wait 30 days (15 days in the case of a cash tender offer or a bankruptcy)" before closing, according to the agency's merger review process guide. The details matter more than most explainers admit:
- The period ends at 11:59 p.m. Eastern on its last day.
- Weekends and holidays push it out. If the last day falls on a weekend or federal holiday, the FTC says the period runs to 11:59 p.m. ET on the next business day.
- Early termination exists and is being used. The FTC's public notice list shows grants dated as recently as October 27, 2026.
Which deals need to file? The FTC's 2026 figures took effect on February 17, 2026. The size-of-transaction threshold rose to $133.9 million from $126.4 million, and the statute's original $200 million tier now sits at $535.5 million, per the FTC's current thresholds page. One more 2026 wrinkle: after a federal court vacated the expanded HSR form, the FTC said in March 2026 that the pre-February 10, 2025 form and instructions were back in use.
Filing fees scale with deal size. The 2026 schedule from the FTC's filing fee page:
| 2026 size of transaction | 2026 filing fee |
|---|---|
| Less than $189.6 million | $35,000 |
| $189.6 million to under $586.9 million | $110,000 |
| $586.9 million to under $1.174 billion | $275,000 |
| $1.174 billion to under $2.347 billion | $440,000 |
| $2.347 billion to under $5.869 billion | $875,000 |
| $5.869 billion or more | $2,460,000 |
What stretches the clock
Pull-and-refile. If the agencies need a little more time, the buyer can withdraw its filing and refile within two business days without paying a new fee. That restarts a fresh 30-day period (or 15 days for a cash tender). The FTC says this is available only once, and not after the period has expired, after early termination, or after a Second Request. Buyers usually do it to avoid something worse.
The Second Request. This is the escalation investors fear. The agency asks each side for more information and documents, and the waiting period then runs until 30 days after both companies have "substantially complied". For cash tender offers, it is 10 days after the buyer complies. The rule sets no deadline for compliance. Compliance can take months, and the 30-day clock waits for it.
Timing agreements. Parties often promise the agency they will not close before a set date or event. The FTC notes that timing agreements "do not extend or otherwise toll the waiting period". In practice, though, they set the real earliest closing date.
Three 2026 deals, three different clocks
The fast lane: Viatris and Pacira ($PCRX). Viatris is buying Pacira through a $36.50-per-share cash tender offer under a merger agreement signed on October 8, 2026. According to the offer document filed October 30, 2026, both sides made their HSR filings on October 14, 2026, and the 15-day period expired at 11:59 p.m. ET on October 29, 2026, with no timing agreement in place. The regulatory condition was satisfied about three weeks after signing, and the offer is scheduled to expire on November 16, 2026. $PCRX closed at $36.40 on November 2, 2026, $0.10 (about 0.27%) under the offer price. Our Viatris-Pacira deal coverage has the background, and our tender-offer-versus-vote explainer covers why cash tenders get the short clock.
The pull-and-refile: Tempus AI and Personalis ($PSNL). The companies filed on July 31, 2026. On August 31, 2026, Tempus withdrew its filing, refiled on September 2, 2026, and started a new 30-day period, which expired at 11:59 p.m. ET on October 2, 2026, according to a Personalis 8-K filed October 6, 2026. Look at the dates. Thirty days from July 31 lands on Sunday, August 30, so the original period would have rolled to Monday, August 31, the day Tempus pulled. Refiling cost about a month but avoided a Second Request. Patrick Industries and LCI Industries show that refiling does not always work: they withdrew on September 4, 2026, refiled on September 9, 2026, and still received a DOJ Second Request on October 9, 2026.
The long road: Cintas and UniFirst ($UNF). Both companies received FTC Second Requests on June 11, 2026, and certified substantial compliance on October 2, 2026, according to Cintas's October 6, 2026 8-K. That is 113 days of compliance work. On paper, the statutory 30 days after October 2 ran out in early November. But on October 2 the parties also signed a timing agreement not to close before December 11, 2026, unless the FTC closes its investigation sooner. That set the earliest US closing date 70 days after compliance, about 39 days past the statutory date. Canada's Competition Bureau ran its own process alongside, with a Supplementary Information Request issued on July 2, 2026 and answered on September 29, 2026. Cintas still expects a close before the end of 2026. Our Cintas-UniFirst spread analysis covers what that extra risk did to the price.
The HSR calendar for holders
| Event | Typical timing | What it means for holders and spreads |
|---|---|---|
| HSR filing | Set by the merger agreement (Viatris-Pacira: within 15 business days of signing) | Starts the clock. The deadline is usually written into the merger agreement, so the filing itself is rarely a surprise. |
| Early termination | Any time before day 30 (or 15) | The US antitrust condition is met early. The remaining spread mostly reflects other conditions and time. |
| Expiration | Day 30 (15 for cash tenders), 11:59 p.m. ET, rolled to the next business day if needed | Removes a condition, not all risk. The agencies can still sue. |
| Pull-and-refile | Refile within 2 business days, then a new 30 (or 15) days | Adds about a month and signals the agency has questions. Arb desks watch for this. |
| Second Request | Runs to 30 days after substantial compliance (10 for cash tenders). Cintas-UniFirst took 113 days to comply. | Closing dates slide, and spreads can widen to price in litigation or remedy risk, as Cintas-UniFirst's did around FTC news. |
| Timing agreement | A negotiated date (Cintas-UniFirst: no close before December 11, 2026) | Sets the realistic earliest close, which matters for annualized spread math. |
The common mistake: "HSR expired" does not mean "deal approved"
When Valaris and Transocean said on September 30, 2026 that the DOJ had closed its investigation and the waiting period had expired, the companies still said only that they "anticipate" a fourth-quarter 2026 close, subject to the remaining conditions. That is the right reading. Our Valaris-Transocean coverage tracked the run-up.
Three reasons expiration is not the finish line:
- The agencies keep their power to sue. The Pacira offer document says that even after the waiting period, the FTC or DOJ could seek to block the deal, force divestitures or impose conditions. The FTC's guide says parties may close at the end of the waiting period unless the agency obtains a court order stopping the merger.
- Other approvals are separate. These can include Canada's Competition Bureau, UK reviews (as in Brink's NCR Atleos deal), state regulators, CFIUS for foreign buyers, and shareholder votes.
- HSR clearance can expire. Western Union and International Money Express ($IMXI) said in an 8-K filed October 2, 2026 that HSR clearance lasts one year from expiration. Their original period expired on October 6, 2025, and California's financial regulator had suspended its approval. Because they did not expect California to reinstate its approval before that anniversary, they filed again on October 2, 2026, starting a new 30-day period.
The HSR checklist
- Find the filing date in the proxy, the offer document or an 8-K, and count 30 days (or 15). Roll a weekend or federal holiday to the next business day.
- Check whether early termination was requested and whether it appears on the FTC's notice list.
- Look for "withdrew" and "refiled". One pull is common. A Second Request after a pull is a warning sign.
- If a Second Request arrives, the date to watch is substantial compliance, not the date the request was issued.
- Look for a timing agreement date. It is often the real earliest close.
- List every other approval: foreign antitrust, CFIUS, state regulators and the shareholder vote.
For more deal-mechanics explainers, browse the Analysis section or the What's On Finance homepage. This is general information, not legal advice.
Bull/Bear Verdict
Bull Case: The HSR clock runs on fixed rules, so investors who read the filing dates can usually see delays coming before the headlines do. Pacira went from signing to a satisfied antitrust condition in about three weeks, and Personalis absorbed a refile without a Second Request.
Bear Case: The headline "waiting period expired" misleads investors who stop there. Second Requests have no compliance deadline, timing agreements can push a close well past the statutory date (to December 11, 2026 at Cintas-UniFirst), the agencies can still sue after expiration, and non-HSR approvals can stall a deal long after the US clock has run.
FAQ
How long is the HSR waiting period?
Thirty days after a complete filing, or 15 days for a cash tender offer or certain bankruptcy sales. It ends at 11:59 p.m. ET and rolls to the next business day if the last day falls on a weekend or federal holiday.
What is the HSR filing threshold in 2026?
The 2026 size-of-transaction threshold is $133.9 million, effective February 17, 2026. Filing fees range from $35,000 for deals under $189.6 million to $2,460,000 for deals of $5.869 billion or more.
Is early termination available in 2026?
Yes. The FTC's public list shows early termination grants dated as recently as October 27, 2026. The parties have to request it, and the agencies decide whether to grant it.
Does a Second Request mean the deal will be blocked?
No. It means a deeper investigation. The waiting period then runs until 30 days after the parties substantially comply. Cintas and UniFirst took 113 days to comply and still expected to close before the end of 2026.