Hart-Scott-Rodino Act: 2025 Updates & Impact on Australian Deals

When Australian companies eye a merger or acquisition involving US assets or investors, there’s a crucial regulatory hurdle to consider: the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (HSR Act). In 2025, this long-standing US law is more relevant than ever, as global dealmaking intensifies and regulatory scrutiny tightens. Whether you’re a CFO, corporate counsel, or savvy investor, understanding the HSR Act’s reach—and its 2025 updates—could save your deal from costly delays or legal headaches.

What Is the Hart-Scott-Rodino Act and Why Does It Matter Down Under?

Enacted in 1976, the HSR Act was designed to give US regulators advance notice of large mergers and acquisitions. This pre-merger notification requirement gives the Federal Trade Commission (FTC) and the Department of Justice (DOJ) time to assess whether a proposed deal could harm competition. While it’s a US law, its impact is global—any transaction involving US assets, companies, or investors could trigger HSR filing requirements, regardless of where the buyer is based.

For Australian firms, this means that cross-border deals—especially those with US targets or substantial US sales—can fall under the HSR umbrella. Ignore it, and you risk multi-million-dollar penalties or even deal unwind orders.

• HSR applies to deals over certain thresholds (updated annually)

• Both parties may need to file with US regulators

• Mandatory waiting period (usually 30 days) before closing

In 2025, with more Australian companies expanding into the US tech, energy, and healthcare sectors, HSR compliance is increasingly a must-have on the due diligence checklist.

Key 2025 Updates: Thresholds, Filing Fees, and Enforcement Trends

The HSR Act isn’t static—each year, filing thresholds and fees are adjusted for inflation and policy changes. In 2025, the FTC raised the minimum size-of-transaction threshold to USD $120 million (up from $111.4 million in 2024), reflecting rising deal values. This means more deals will now fall below the radar, but those above the threshold face higher scrutiny and costs.

Other notable 2025 changes include:

• Filing fees: The US Congress revamped the fee structure, with larger deals (USD $1 billion+) facing significantly higher fees—up to USD $2.25 million per filing.

• More detailed disclosures: The FTC now demands additional data on deal rationale, supply chain impacts, and ESG considerations, reflecting a wider antitrust lens.

• Crackdown on ‘gun-jumping’: Enforcement against parties that coordinate activities pre-clearance has intensified, with new guidance and penalties handed down in several high-profile cases.

For Australian dealmakers, these changes mean it’s more important than ever to:

• Assess HSR triggers early in the transaction process

• Budget for higher filing fees and potential delays

• Prepare robust documentation to defend the deal’s competitive impact

Real-World Examples: HSR in Action for Australian Companies

Consider the recent acquisition of a US biotech firm by an ASX-listed pharmaceutical company. Despite being headquartered in Sydney, the deal exceeded the HSR threshold due to the US target’s revenue. Both companies were required to file with the FTC, triggering a 30-day waiting period and detailed antitrust review. Thanks to early planning, the deal closed on schedule—but only after responding to regulator requests for additional information on market share and innovation impacts.

Another example: a major Australian infrastructure fund’s bid for a US-based renewables platform. The deal’s complex ownership structure prompted questions from the DOJ about potential overlaps in the energy market. Delays ensued, but proactive engagement and transparent disclosures ultimately secured clearance.

These cases highlight the importance of integrating HSR analysis into Australian firms’ cross-border M&A strategy from day one.

Best Practices for Navigating HSR in 2025

• Map out all deal participants and assets to identify US touchpoints early

• Engage legal counsel with deep HSR experience—ideally with both US and Australian regulatory backgrounds

• Document your deal rationale, including how it will (or won’t) affect competition, supply chains, and consumers

• Prepare for regulator questions—from market share to ESG risks, 2025’s antitrust reviews are broader than ever

• Plan for delays: Even straightforward deals can hit the 30-day waiting period, while more complex ones may prompt ‘second requests’ for info

Conclusion: HSR Is a Global Gatekeeper for Australian M&A

As US-Australian dealmaking accelerates in 2025, the Hart-Scott-Rodino Act remains a critical (and often underestimated) regulatory gatekeeper. Failing to factor HSR into your deal timeline or due diligence can derail even the most promising cross-border transaction. But with early planning, transparent disclosures, and expert advice, Australian companies can turn HSR compliance from a roadblock into a competitive advantage.