Every year, the Federal Trade Commission adjusts the filing thresholds under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (the HSR Act) to account for changes in gross national product. These thresholds determine which mergers and acquisitions must be reported to the FTC and DOJ before they can close. For businesses planning acquisitions, investments, or joint ventures, understanding whether your transaction triggers HSR filing obligations is one of the first — and most consequential — questions in the deal process.

What the HSR Act Requires

The Hart-Scott-Rodino Act requires parties to certain mergers, acquisitions, and other transactions to file pre-merger notifications with the FTC and DOJ and observe a mandatory waiting period before completing the transaction. The purpose is to give federal antitrust agencies the opportunity to review transactions that may substantially lessen competition before they become irreversible.

Filing is triggered when a transaction meets certain size thresholds — known as the "size-of-transaction" test and, in some cases, the "size-of-person" test. The filing fee, which also adjusts annually, can be substantial for large transactions.

The mandatory waiting period is 30 days for most transactions (15 days for cash tender offers), during which the agencies review the filing and decide whether to investigate further. If the agencies issue a "second request" — a detailed demand for documents and information — the waiting period extends until both parties have substantially complied with the request, which can add months to the deal timeline.

2026 HSR Filing Thresholds

The FTC publishes revised thresholds annually, typically effective in late February or early March. For 2026, the revised thresholds took effect on February 17, 2026, and the key numbers that businesses and their counsel should know are as follows.

The minimum size-of-transaction threshold — the starting point for any HSR analysis — is $133.9 million for 2026, up from $126.4 million in 2025. Transactions valued below this amount do not require HSR filing regardless of the size of the parties. Any transaction in which the acquiring person will hold an aggregate amount of voting securities, assets, or interests exceeding $133.9 million must evaluate whether filing is required.

For transactions between $133.9 million and $535.5 million, the size-of-person test applies as an additional filter. One party must have total assets or annual net sales of at least $267.8 million, and the other party must have total assets or annual net sales of at least $26.8 million. This means that a transaction between two small companies may not require filing even if the deal value exceeds the minimum threshold — a nuance that can save parties significant time and expense.

Above the $535.5 million upper size-of-transaction threshold, filing is required regardless of the size of the parties. This bright-line rule ensures that all large transactions receive antitrust review.

Common HSR Filing Mistakes

The HSR filing process is more complex than many deal teams anticipate, and errors can result in significant penalties. The maximum civil penalty for HSR violations is $54,540 per day for 2026 (up from $53,088 in 2025), and cumulative penalties in enforcement actions have reached into the millions — the FTC imposed a record $5.6 million settlement for gun-jumping violations in early 2025.

Failing to Identify Reportable Transactions

Not every acquisition is obvious. The HSR Act applies to acquisitions of voting securities, assets, and non-corporate interests (such as LLC membership interests and partnership interests). It also applies to certain incremental acquisitions — when an acquiring person who already holds securities in a target crosses a new notification threshold by acquiring additional shares. Deal teams sometimes fail to aggregate prior holdings or to account for convertible securities and options when calculating whether the thresholds are met.

Miscalculating Transaction Value

The "size-of-transaction" test requires determining the "value" of the acquisition, which is not always the same as the purchase price. For voting securities, value is the greater of the acquisition price or the market price. For assets, value is the greater of the acquisition price or the fair market value. For transactions structured as asset purchases with assumed liabilities, the treatment of liabilities in the valuation calculation requires careful analysis.

Missing Exemptions

The HSR Act includes numerous exemptions that can eliminate the filing obligation for transactions that otherwise meet the thresholds. Commonly applicable exemptions include acquisitions of goods in the ordinary course of business, acquisitions of real property, acquisitions of foreign assets (with limited U.S. nexus), and certain acquisitions by institutional investors who hold securities solely for investment purposes. Identifying applicable exemptions early in the deal process can save parties the cost and delay of an unnecessary filing.

Closing Before Clearance

Perhaps the most serious HSR violation is completing a transaction before the waiting period has expired — known as "gun jumping." Gun-jumping violations can result in civil penalties, and the agencies have pursued gun-jumping cases even when the underlying transaction raised no substantive antitrust concerns. Parties must also be careful to avoid exchanging competitively sensitive information or exercising operational control over the target during the pre-closing period, which can constitute gun jumping even if the formal closing has not occurred.

The HSR Filing Process

Preparing the Filing

An HSR filing requires both parties (the acquiring person and the acquired person) to submit separate notification forms (the HSR Form) to the FTC and DOJ. The form requires detailed information about the parties' business operations, the structure of the transaction, and the industries in which the parties compete.

The filing landscape has shifted significantly in the past two years. In October 2024, the FTC adopted dramatically expanded HSR filing rules — effective February 10, 2025 — that required approximately 20 new categories of information, including narrative descriptions of the competitive rationale for the deal, details about labor market effects, and information about prior acquisitions. However, on February 12, 2026, a federal district court in Texas vacated the new rules, finding the FTC failed to justify their costs relative to their benefits. The Fifth Circuit denied the FTC's motion for a stay on March 19, 2026, meaning the pre-2025 HSR Form is currently back in effect. Filers may still voluntarily submit filings under the expanded format, but the simpler, pre-2025 form is now the standard. Businesses should monitor this area closely, as the FTC and DOJ announced a new public inquiry into the effectiveness of premerger notifications on March 25, 2026, with comments due May 26, 2026.

Filing Fees

HSR filing fees are based on the size of the transaction and are paid by the acquiring person. For 2026, the six-tier fee schedule (effective February 17, 2026) is:

Less than $189.6 million: $35,000
$189.6 million to less than $586.9 million: $110,000
$586.9 million to less than $1.174 billion: $275,000
$1.174 billion to less than $2.347 billion: $440,000
$2.347 billion to less than $5.869 billion: $875,000
$5.869 billion or more: $2,460,000

The filing fee is non-refundable, even if the transaction is later abandoned.

Agency Review and Second Requests

During the initial waiting period, the assigned agency (FTC or DOJ — they divide responsibility by industry) conducts a preliminary review. Most transactions are cleared without any action — the agencies allow the waiting period to expire, and the parties are free to close.

One significant positive development: the agencies resumed granting early termination of the HSR waiting period in early 2025, after suspending the practice in 2021. Early termination allows parties to close before the full 30-day waiting period expires when the transaction poses no competitive concerns — a welcome change for deal teams operating on tight timelines.

For transactions that raise potential competitive concerns, the agency may issue a second request, which is essentially a detailed investigation of the transaction's competitive effects. Second requests are resource-intensive and can take six months or longer to complete.

Negotiating Remedies

If the agency concludes that the transaction would substantially lessen competition, it may seek to block the deal through litigation or negotiate remedies — typically divestitures of overlapping business lines or assets. OTT Law advises clients on structuring remedies that preserve the commercial value of the transaction while satisfying the agency's competitive concerns.

Missouri-Specific Considerations

While HSR filing is a federal obligation, Missouri businesses should be aware that the Missouri Attorney General also has authority to challenge mergers under RSMo Chapter 416 — Missouri's state antitrust law. The AG can seek injunctive relief to block transactions that substantially lessen competition in Missouri markets, even if the federal agencies have cleared the deal. This has become increasingly relevant as state AGs have asserted a more active role in merger review, particularly in healthcare, agriculture, and technology markets.

Businesses planning transactions that affect Missouri markets should consider both federal HSR obligations and the potential for state-level scrutiny — a dynamic we explore in our analysis of antitrust law developments Missouri businesses should watch. For transactions involving securities or complex M&A structures, the regulatory picture extends well beyond HSR. OTT Law provides integrated antitrust counsel that addresses both federal and Missouri merger review requirements.

Frequently Asked Questions

Does every acquisition require an HSR filing?

No. Filing is required only when the transaction meets the size-of-transaction threshold (and, for mid-range transactions, the size-of-person test) and no exemption applies. Many acquisitions — including small transactions, ordinary-course purchases of goods, and certain real estate acquisitions — are exempt from filing requirements. However, the analysis is fact-specific, and parties should evaluate HSR obligations early in the deal process to avoid penalties.

What happens if we close a transaction without filing?

Completing a reportable transaction without filing (or before the waiting period expires) is a serious violation of the HSR Act. The FTC can seek civil penalties of up to $54,540 per day for each day the violation continues in 2026. The agencies have pursued gun-jumping cases even when the merger raised no substantive competitive concerns, and cumulative penalties have reached into the millions of dollars — including a record $5.6 million settlement in 2025. If you realize that a completed transaction should have been reported, contact antitrust counsel immediately.

How long does the HSR review process take?

The initial waiting period is 30 days (15 days for cash tender offers). If the agencies do not issue a second request during that period, the parties are free to close. If a second request is issued, the timeline extends significantly — typically six to twelve months for complex investigations. The total timeline depends on the complexity of the competitive issues, the scope of the documents and data involved, and the parties' willingness to negotiate remedies.

If your business is planning a merger, acquisition, or investment that may trigger HSR filing obligations, early analysis is critical. Understanding where your transaction falls within the antitrust framework — and whether federal or state-level scrutiny may apply — can save significant time, cost, and risk. Contact OTT Law at (314) 710-2740 for a consultation.

This article is for informational purposes only and does not constitute legal advice. Every case is different. Contact OTT Law at (314) 710-2740 for a free consultation specific to your situation.

HSR Filing Thresholds for 2026