The Disciplines of M&A
The competition filing: who must notify, on what clock, in how many places at once, and what a regulator can actually do about a deal it dislikes.
Merger control is the body of law that allows a state to examine, and if necessary block or condition, a change of corporate control before it takes effect. Its rationale is preventive: conduct rules such as abuse-of-dominance and cartel prohibitions operate after harm has occurred, whereas a completed merger permanently alters market structure and is difficult to unwind. Regimes therefore intervene at the point of transaction, applying a forward-looking counterfactual test.
The substantive standards converge more than the procedures do. Most jurisdictions ask whether a transaction would substantially lessen competition (the United States, United Kingdom, Australia, Canada, South Africa) or significantly impede effective competition (the European Union and regimes modelled on it). China applies an effects test that also admits industrial-policy considerations, and South Africa layers an express public-interest assessment on top of the competition test. The practical divergence lies in who must file, when, for how long the parties are frozen, and who bears the burden of proof.
Almost all regimes use objective, mechanical thresholds — turnover, assets, or transaction value — rather than a substantive filter, so that filing obligations can be determined with certainty. Thresholds are typically cumulative: a global size test paired with a local nexus test. Because turnover thresholds miss acquisitions of pre-revenue targets, a second generation of tests has emerged based on deal value plus a local activity nexus.
The first-phase clock, by jurisdiction
| Jurisdiction | Filing | Effect | Second phase |
|---|---|---|---|
| United States | Mandatory | Suspensory | open-ended (second request); waiting period ends 30 days after substantial compliance |
| European Union | Mandatory | Suspensory | 90 working days, extendable to 125 |
| United Kingdom | Voluntary | Non-suspensory | 24 weeks, extendable by 8 weeks |
| China | Mandatory | Suspensory | 90 days further review plus a further 60-day extension |
| Germany | Mandatory | Suspensory | second-phase proceedings averaged 176 days in 2025 |
| Japan | Mandatory | Suspensory | second-phase review |
| Australia | Mandatory | Suspensory | up to 90 business days |
| Saudi Arabia | Mandatory | Suspensory | no separate phase 2 stated; review suspendable on information requests |
| India | Mandatory | Suspensory | not stated in source |
| Brazil | Mandatory | Suspensory | fixed statutory outer limit rather than open-ended review |
| Canada | Mandatory | Suspensory | not stated in source |
| Turkey | Mandatory | Suspensory | not stated in source |
| South Africa | Mandatory | Suspensory | not stated in source |
A suspensory (or standstill) regime prohibits closing until clearance. This is the global norm: the US, EU, China, Germany, India, Japan, Brazil, Canada, Saudi Arabia, Turkey, South Africa and — from 1 January 2026 — Australia all operate mandatory suspensory systems, and implementing before clearance ("gun-jumping") attracts fines. The United Kingdom is the principal outlier: notification is voluntary and there is no automatic standstill, but the Competition and Markets Authority routinely imposes initial enforcement orders freezing integration, producing a suspensory effect on cases it chooses to examine.
Reviews are almost universally two-staged. Phase 1 is a short screening period in which the large majority of deals are cleared; Phase 2 is a longer, evidence-heavy investigation reserved for cases raising a plausible theory of harm.
Where concerns arise, parties may offer commitments. Structural remedies (divestiture of a business) are preferred by most agencies because they are self-executing; behavioural remedies require monitoring and have historically been disfavoured, although the CMA moved away from that presumption in December 2025. Outright prohibition is rare. Appeal routes differ sharply: in the EU, UK, China and most civil-law systems the agency decides and the parties appeal; in the United States the agencies cannot themselves block a deal and must persuade a federal court to enjoin it.
The Hart-Scott-Rodino Antitrust Improvements Act of 1976, codified at Section 7A of the Clayton Act, requires premerger notification to both the Federal Trade Commission and the Department of Justice Antitrust Division. Thresholds are indexed annually to gross national product. For 2026 the FTC set the base size-of-transaction threshold at $133.9 million, up from $126.4 million; the upper threshold above which the size-of-person test falls away rose to $535.5 million from $505.8 million; and the size-of-person tests rose to $26.8 million and $267.8 million. They apply to transactions closing on or after the effective date of the Federal Register notice, 30 days after publication.
Filing fees for 2026 are tiered by transaction value: $35,000 below $189.6 million; $110,000 from $189.6 million to below $586.9 million; $275,000 to below $1.174 billion; $440,000 to below $2.347 billion; $875,000 to below $5.869 billion; and $2,460,000 at $5.869 billion or above.
The FTC finalised a substantially expanded HSR form in late 2024, effective 10 February 2025. It required narrative competition overviews, a broader set of transaction documents, supply-relationship and prior-acquisition data, and minority-holder disclosure; the FTC's burden estimate rose from roughly 37 hours to 105 hours per filing. On 12 February 2026 the US District Court for the Eastern District of Texas vacated the 2025 HSR rules in Chamber of Commerce v. FTC, No. 6:25-cv-00009, and on 19 March 2026 the Fifth Circuit denied the FTC's motion to stay that judgment. The FTC is accordingly accepting filings on the form and instructions in force before 10 February 2025, with the appeal pending; the FTC's appellate brief was due 20 April 2026. Filers may still submit voluntarily under the 2025 format.
The FTC and DOJ jointly issued new Merger Guidelines in December 2023, replacing the 2010 horizontal and 2020 vertical guidance. They set out a series of numbered frameworks, including structural presumptions from market concentration and theories addressing elimination of potential competition, entrenchment of dominance, serial acquisitions, multi-sided platforms and effects on workers. The specific concentration screens (commonly reported as a Herfindahl-Hirschman Index above 1,800 with an increase above 100, or a combined share above 30 per cent with an increase above 100) could not be verified against a primary source in this pass and are stated here as reported only. On 18 February 2025, FTC Chair Andrew Ferguson and Acting Assistant Attorney General Omeed Assefi issued memoranda confirming the 2023 Guidelines remain in effect, Ferguson citing the value of stability and warning against rescission with each change of administration.
The statutory initial waiting period is 30 days from filing (15 days for cash tender offers and certain bankruptcy sales); these figures are long-established but were not confirmed against a primary source here. If the agencies want more, they issue a Request for Additional Information and Documentary Material — a "second request" — which extends the waiting period until 30 days after substantial compliance. Because compliance can take many months, parties routinely negotiate timing agreements under which they commit not to close for a defined period after certifying compliance in exchange for narrowed custodians and search terms. Parties may also withdraw and refile to restart the initial period.
Expiry of the waiting period does not confer clearance. To stop a deal the agency must sue in federal court for a preliminary injunction, bearing the burden of proof; alternatively it may settle by consent decree, typically requiring divestiture to an approved buyer.
The second Trump administration retained the 2023 Guidelines but re-opened the settlement channel. Analysis of significant US merger investigations recorded five consent decrees in the second quarter of 2025 alone — more than in the preceding nine quarters combined — including Synopsys/Ansys, Keysight/Spirent, Safran/Collins Aerospace, Alimentation Couche-Tard/Giant Eagle and HPE/Juniper. Duration nonetheless lengthened: the average significant US merger investigation ran 12.6 months in the first half of 2025 against 11.3 months in 2024. Structural remedies are favoured and behavioural remedies remain disfavoured, with the agencies stepping back from prior-approval provisions in decrees.
Council Regulation (EC) No 139/2004 (the EU Merger Regulation) gives the European Commission exclusive jurisdiction over concentrations with an EU dimension. Under Article 1(2), that arises where combined worldwide turnover exceeds EUR 5,000 million and each of at least two undertakings concerned has EU-wide turnover above EUR 250 million. Article 1(3) provides an alternative: combined worldwide turnover above EUR 2,500 million; combined turnover above EUR 100 million in each of at least three Member States; in each of those three, at least two undertakings each with turnover above EUR 25 million; and at least two undertakings each with EU-wide turnover above EUR 100 million. Both limbs are disapplied where each undertaking concerned achieves more than two-thirds of its EU-wide turnover in one and the same Member State.
Article 22 allows Member States to refer a concentration to the Commission. From 2021 the Commission encouraged referrals of below-threshold deals, principally to capture acquisitions of nascent competitors, and used the mechanism to review Illumina's acquisition of GRAIL. On 3 September 2024 the Court of Justice, in Cases C-611/22 P and C-625/22 P, set aside the General Court's judgment and annulled the referral decisions, holding that a Member State cannot refer a transaction that does not meet its own national merger control thresholds. Article 22 reverted to its original function as a mechanism for states lacking their own regimes. The Commission had already fined Illumina EUR 432 million for gun-jumping in July 2023, and Illumina completed divestment of GRAIL on 24 June 2024. Reports indicate the Commission subsequently withdrew several decisions in the case; that step could not be verified against a primary source here. The practical consequence has been a shift of below-threshold capture to national call-in powers, which several Member States have introduced or expanded.
Phase I runs 25 working days from formal notification, extended to 35 working days where commitments are offered or a Member State referral request is made. Phase I outcomes are clearance under Article 6(1)(b), clearance with commitments under Article 6(1)(b) read with Article 6(2), or referral to Phase II under Article 6(1)(c). Phase II runs 90 working days, extendable by 15 working days where remedies are submitted after day 55 and by a further 20 working days at the parties' request or with their agreement, giving a maximum of 125 working days. Phase II decisions are unconditional clearance (Article 8(1)), conditional clearance (Article 8(2)) or prohibition (Article 8(3)). Failure to notify or premature implementation is punishable under Article 14 by fines of up to 10 per cent of aggregate worldwide group turnover. Timelines have lengthened in practice: Phase I remedy cases averaged 12.1 months from announcement in the first half of 2025.
The Commission launched a review of its substantive guidance in 2025 and published draft Merger Guidelines for public consultation on 30 April 2026, with comments due by 26 June 2026 and adoption targeted for 1 December 2027. The draft consolidates the 2004 Horizontal and 2008 Non-Horizontal Guidelines into a single instrument, articulates eight theories of harm including loss of innovation and loss of investment and expansion competition, gives efficiencies greater analytical weight, expands the parameters of competition considered to include investment, innovation, privacy, sustainability and resilience, and proposes a safe harbour for small innovative firms.
The Enterprise Act 2002 regime is voluntary and non-suspensory in form: there is no obligation to notify and no automatic standstill. In practice the CMA monitors deal activity, opens own-initiative investigations, and routinely imposes initial enforcement orders preventing integration pending review, so the regime operates suspensorily for any deal it takes up. Reference to Phase 2 triggers an inquiry-group investigation under a statutory timetable; the commonly cited periods of 40 working days for Phase 1 and 24 weeks for Phase 2, extendable by 8 weeks, were not verified against a primary source in this pass.
The Digital Markets, Competition and Consumers Act 2024 changed jurisdictional reach with effect from 1 January 2025. The target turnover test rose from £70 million to £100 million. The 25 per cent share of supply test was retained. A new hybrid test was added: jurisdiction arises where one party has a share of supply of at least 33 per cent in the United Kingdom or a part of it and UK turnover exceeding £350 million, and the other party has a UK nexus, with no requirement of any overlap or increment between the parties' activities — a test aimed at killer acquisitions and conglomerate expansion. A safe harbour exempts mergers where each party has UK turnover of £10 million or less, though media plurality cases retain the £70 million figure.
Posture shifted materially in 2025 under government pressure for a growth-oriented regulator. The CMA published a Mergers Charter on 12 March 2025 built on four commitments — pace, predictability, proportionality and process — and set internal targets of 25 working days for straightforward Phase 1 cases (against an average of about 35) and 40 working days for pre-notification (against 65 or more). Only two Phase 2 references were made in 2025, Aramark/Entier and Constellation/ABVR. On 19 December 2025 the CMA published revised remedies guidance removing the presumption against behavioural remedies at Phase 1, broadening the effectiveness assessment and accepting, in local-market cases, divestitures that do not remove the whole merger increment. Vodafone/Three, cleared on network investment commitments reported at £11 billion together with price caps, exemplifies the change.
The State Administration for Market Regulation administers a mandatory, suspensory regime under the Anti-Monopoly Law. Thresholds were raised for the first time since 2008 with effect from 26 January 2024: a filing is required where combined worldwide turnover exceeds RMB 12 billion or combined China turnover exceeds RMB 4 billion, and in either case each of at least two parties has China turnover exceeding RMB 800 million. The previous figures were RMB 10 billion, RMB 2 billion and RMB 400 million; the change was projected to cut filings by roughly 30 per cent.
Two features shape timetables. First, the statutory clock starts only on case acceptance, and the pre-acceptance completeness review has been reported to take two to six weeks. The statutory review structure — 30 days of preliminary review, 90 days of further review and a further 60-day extension — is well established but was not verified against a primary source in this pass. Second, parties in complex cases withdraw and refile to reset the clock, so headline statutory periods understate elapsed time; conditional clearances in semiconductors and chemicals have run well beyond a year. Routine cases move quickly: simplified-procedure filings were 89.2 per cent of cases reviewed in the first quarter of 2024 with an average review of 17.3 days, and the 2023 average from Phase 1 initiation was approximately 25.5 days. SAMR's leverage over transactions with limited Chinese nexus but significant Chinese sales has made it a recurring gating item on global deals.
Germany. The Bundeskartellamt requires notification where combined worldwide turnover exceeds EUR 500 million, one undertaking has German turnover above EUR 50 million and another above EUR 17.5 million. A transaction value threshold of EUR 400 million applies where the target has German turnover below EUR 17.5 million but substantial domestic operations. A twelfth draft amendment to the German competition act, published 4 June 2026, would raise these to EUR 750 million, EUR 75 million and EUR 20 million, make the transaction value test a standing limb, and add a two-week preliminary "simplified notice" stage; timing of entry into force is uncertain. Phase 1 is one month; second-phase proceedings averaged 176 days in 2025.
India. The Competition Commission of India operates a mandatory suspensory regime. From 10 September 2024 a deal value threshold applies: transactions above INR 2,000 crore require notification where the target has substantial business operations in India, defined by tests keyed to 10 per cent of global gross merchandise value, turnover or users, with an INR 500 crore floor in non-digital sectors.
Japan. The Japan Fair Trade Commission runs a mandatory suspensory regime with a 30-day waiting period and a second-phase review, and has become more active in global technology deals. Its turnover thresholds (widely cited as domestic turnover above JPY 20 billion for the acquirer group and JPY 5 billion for the target) were not verified in this pass.
Brazil. CADE operates a mandatory suspensory regime with a fast-track procedure and a fixed statutory outer limit rather than an open-ended review. Its turnover thresholds (commonly cited as BRL 750 million for one group and BRL 75 million for the other) were not verified here.
Australia. A mandatory suspensory regime administered by the ACCC took effect on 1 January 2026, replacing an informal voluntary system. Notification is required where combined Australian turnover of acquirer and target is at least AUD 200 million and either target Australian turnover is at least AUD 50 million or global transaction value is at least AUD 250 million; or, for acquirer groups with Australian turnover of at least AUD 500 million, where target turnover is at least AUD 10 million. From 1 October 2025 acquirers whose deals would complete after 31 December 2025 had to use the new system. Phase 1 runs up to 30 business days and Phase 2 up to 90 business days. Fees are AUD 56,800 for Phase 1 and AUD 475,000, AUD 855,000 or AUD 1,595,000 at Phase 2 by transaction value.
Canada. Pre-merger notification under the Competition Act is mandatory and suspensory where the transaction-size threshold of C$93 million and the party-size threshold of C$400 million are both met. The transaction-size figure was held at C$93 million for 2026.
Saudi Arabia and the Gulf. The General Authority for Competition requires notification where combined worldwide turnover exceeds SAR 200 million, target turnover exceeds SAR 40 million and combined Saudi turnover exceeds SAR 40 million, thresholds in force since 1 November 2023. The statutory review is 90 days from confirmation of completeness, suspendable on information requests. Filing volumes have risen steeply — 316 notifications in 2022, 62 per cent concerning foreign transactions — making the Gulf a routine item in multi-jurisdictional analysis rather than an exception.
Turkey. The Turkish Competition Authority operates a mandatory suspensory regime under Communiqué No. 2010/4, with turnover-based thresholds and a broad approach to local nexus that captures many foreign-to-foreign deals. Current threshold figures were not verified in this pass.
South Africa. The Competition Commission and Competition Tribunal apply both a competition test and a statutory public-interest test covering employment, the ability of small and historically disadvantaged firms to compete, and the spread of ownership. Conditions on job guarantees, local procurement and ownership participation are common even absent a competition concern. Threshold figures for intermediate and large mergers were not verified in this pass.
Multi-jurisdictional filing analysis has become a discrete workstream conducted before signing. Practitioners map turnover, assets and local nexus against every plausible regime, distinguishing mandatory suspensory filings that gate closing from voluntary or post-closing regimes that do not. The output is a filing list and a critical path, and increasingly the count itself drives the timetable: a deal requiring twenty or more filings is paced by the slowest of them.
That analysis converts into contract terms. Long-stop dates are set by reference to the slowest expected clearance, with automatic extensions where antitrust conditions remain outstanding. Efforts covenants range from reasonable best efforts to "hell or high water" obligations requiring the buyer to accept any remedy, including divestitures and litigation against the agencies, to obtain clearance; the level of covenant is a negotiated allocation of regulatory risk. Where a buyer resists an absolute covenant, sellers typically extract a reverse termination fee payable if the deal fails on antitrust grounds. Conditionality risk is priced into the offer, and public-market spreads widen with each additional contested jurisdiction.
Three structural shifts have compounded this. Below-threshold capture through national call-in powers, the UK hybrid test and deal value thresholds means turnover screens no longer reliably establish that no filing is required. Divergence in outcome — one agency clearing unconditionally while another demands a global divestiture — creates the risk of remedies that are not co-ordinated across regimes. And gun-jumping enforcement, with exposure up to 10 per cent of group turnover in the EU, constrains integration planning and information exchange across what are now routinely long periods between signing and closing.