Hart-Scott-Rodino Act: 2026 Updates & Impact on Australian Deals

The HSR Act is a US law that requires parties to certain large mergers and acquisitions to notify US regulators before completing their transaction. The purpose is to give the Federal Trade Commission (FTC) and the Department of Justice (DOJ) time to review deals that could potentially harm competition in US markets. While the law is American, its reach is global: any transaction involving US assets, companies, or investors may trigger HSR filing requirements, regardless of where the buyer is based.

For Australian companies, this means that cross-border deals—especially those involving US targets or significant US sales—can fall under the HSR regime. Failing to comply can result in substantial penalties or orders to unwind the transaction.

Key points to keep in mind:

• HSR applies to deals above certain monetary thresholds, which are updated annually.
• Both parties may need to file with US regulators.
• There is a mandatory waiting period (typically 30 days) before closing.

With more Australian firms expanding into US sectors such as technology, energy, and healthcare, HSR compliance is increasingly important in the due diligence process.

The HSR Act is updated each year to reflect changes in deal values and policy priorities. In 2026, the minimum size-of-transaction threshold has increased, meaning some smaller deals may no longer require notification, while larger deals remain subject to review.

Notable 2026 changes include:

• Thresholds: The minimum size-of-transaction threshold has been raised, so only deals above this level require HSR notification. The specific threshold is updated annually by the FTC.
• Filing fees: The fee structure has changed, with larger transactions facing higher filing fees. This means budgeting for these costs is more important than ever.
• Disclosure requirements: Regulators now expect more detailed information about the deal, including rationale, potential supply chain impacts, and broader market considerations.
• Enforcement trends: There is increased attention on parties that coordinate activities before receiving clearance (known as ‘gun-jumping’), with regulators issuing new guidance and penalties in recent cases.

For Australian dealmakers, these updates mean it is crucial to:

• Assess whether HSR is triggered early in the transaction process.
• Budget for filing fees and potential regulatory delays.
• Prepare thorough documentation to explain the deal’s competitive impact.

Australian companies may encounter HSR requirements in several scenarios:

• Acquiring a US-based company or assets above the threshold.
• Merging with a US entity.
• Investing in a US business where the transaction size meets or exceeds the threshold.

Even if the acquiring company is headquartered in Australia, the presence of US assets or significant US sales can bring the deal within HSR’s scope. Both parties may need to file, and the deal cannot close until the waiting period has expired or regulators have completed their review.

Early Assessment

Identifying whether HSR applies should be part of the initial deal planning. This involves mapping out all participants, assets, and revenue streams to determine if US connections exist and if the transaction size meets the threshold.

Legal and Financial Advice

Engaging advisors with experience in both Australian and US regulatory environments is essential. Legal counsel familiar with HSR can help navigate the process, prepare filings, and respond to regulator queries.

Documentation and Transparency

Regulators may request detailed information about the deal’s rationale, market impact, and potential effects on competition or supply chains. Preparing this documentation in advance can help avoid delays.

Managing Timelines

The standard HSR waiting period is 30 days, but more complex deals can face extended reviews if regulators request additional information. Factoring this into the transaction timeline is important to avoid surprises.

Budgeting for Costs

With filing fees increasing for larger deals, it is important to account for these expenses early in the process.

Australian companies have encountered HSR requirements in a range of transactions, such as:

• Acquiring a US technology or healthcare firm with significant US revenue.
• Investing in US infrastructure or energy assets where the deal size meets the threshold.
• Merging with a US-based business, even if the Australian company is the acquirer.

In these cases, early planning and proactive engagement with regulators have helped Australian firms navigate the process and complete their transactions on schedule.

• Identify US connections early: Map out all deal participants and assets to determine if HSR applies.
• Engage experienced advisors: Work with legal counsel who understand both US and Australian regulatory frameworks.
• Prepare comprehensive documentation: Be ready to explain the deal’s rationale and its impact on competition and supply chains.
• Anticipate regulator questions: Expect broader scrutiny, including questions about market share and potential risks.
• Plan for possible delays: Even straightforward deals can face the standard waiting period, while complex transactions may require additional information and time.

As cross-border dealmaking between Australia and the US accelerates in 2026, the Hart-Scott-Rodino Act remains a central regulatory consideration. Factoring HSR compliance into your transaction planning and due diligence can help avoid costly setbacks and keep your deal on track. With early assessment, transparent disclosures, and expert advice, Australian companies can approach US-linked deals with greater confidence.