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Unilateral effects meaning

What does Unilateral effects mean?
Unilateral effects describe, in merger control practice, the risk that a merger allows the combined firm to profitably worsen competitive outcomes—most commonly by raising prices, but also by reducing quality, choice or innovation—because rivalry between the merging parties is removed. The concept is not defined in statute; it is a descriptive theory of harm developed in case law and guidance (including the CMA’s Merger Assessment Guidelines and the CCPC’s merger guidelines). Assessment focuses on how closely the parties compete, diversion ratios, margins, product differentiation, capacity and bidding dynamics. Tools may include upward pricing pressure (UPP/GUPPI) and analysis of internal documents and customer switching. High market shares or dominance are not prerequisites; unilateral effects can arise even without coordinated behaviour. In the UK (England & Wales, Scotland and Northern Ireland), the CMA assesses unilateral effects under the Enterprise Act 2002’s substantial lessening of competition (SLC) test. In Ireland, the CCPC applies an equivalent SLC standard under the Competition and Consumer Protection Act 2014. Usage is broadly consistent across these jurisdictions. Evidence of likely unilateral effects can lead to prohibition, a Phase 2 investigation, or remedies (such as divestments or behavioural commitments) in horizontal mergers and, where relevant, in non-price dimensions.
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NEWS
UK competition law update: CMA provisionally finds SLC in GXO/Wincanton; CAT rejects Apple/Amazon CPO appeal; amended CPOs in MasterCard/Visa merchant service charge claims; upcoming dates

Mergers CMA issues interim report in GXO/Wincanton merger phase 2 investigation; provisionally finds competition concerns The CMA has published its interim report and interim notice on the completed takeover of Wincanton Plc (Wincanton) by GXO Logistics, Inc (GXO). GXO is the world’s largest contract logistics services company. Wincanton, a UK‑based business, also provides these services. Both organisations supply mainstream contract logistics services (CLS) to business customers in retail—such as groceries, fashion, and apparel—and in non‑retail—such as manufacturing and construction—sectors. In its phase 1 review, the CMA determined that the merger gives rise to a realistic prospect of an SLC, stemming from horizontal and unilateral effects in the provision of mainstream CLS across the UK...

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NEWS
UK and EU competition law weekly: CMA mergers, NSI appeal, Intel fine cut, AI platform probes, DMA and State aid (11 December 2025)

In this issue: UK mergers National Investment and Security Act 2021 UK antitrust UK competition policy EU antitrust EU mergers EU Digital Markets Act EU State aid LexTalk®Competition: a Lexis®Nexis community Daily and weekly news alerts Caselex UK mergers Vandemoortele/Délifrance meets the test for reference to a phase 2 The CMA has decided that Vandemoortele Group’s proposed purchase of Délifrance SA satisfies the threshold for a phase 2 referral. Both Vandemoortele and Délifrance supply frozen bakery lines, including croissants and pain au chocolates, to retail and foodservice customers. Those customers bake the products on-site and then sell or serve them to end consumers. At phase 1, the CMA concluded the deal leads to an SLC arising from horizontal unilateral effects in the provision of frozen Laminated Dough (LD) products to retail and foodservice customers across the UK...

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NEWS
UK and EU competition law update: CMA merger and antitrust actions, CAT and Court of Appeal rulings, AI foundation models, home heating review, and State aid developments, 18 April 2024

In this issue: UK mergers UK antitrust UK private actions UK competition policy UK market studies EU state aid Russia’s war against Ukraine LexTalk®Competition: a Lexis®Nexis community Daily and weekly news alerts New and updated content Caselex UK mergers Spreadex/Sporting Index referred to phase 2 The CMA has referred to phase 2 the completed purchase by Spreadex Limited (Spreadex) of the business-to-consumer (B2C) operation of Sporting Index Limited (Sporting Index). Both businesses offer UK customers online fixed-odds betting and online sports spread betting, while Spreadex also provides financial spread betting and casino betting. On 11 April 2024, the CMA confirmed the deal met the threshold for an in-depth investigation. During phase 1, the authority concluded the merger gives rise to an SLC owing to horizontal unilateral effects in the UK supply of licensed online sports spread betting. Notably, the CMA considered that the transaction may have led to a monopoly by eliminating...

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View the related Practice Notes about Unilateral effects

PRACTICE NOTES
CK Telecoms UK v Commission: EU General Court annuls merger prohibition; clarifies unilateral effects, important competitive force, standard of proof, and network-sharing/wholesale analyses under the EU Merger Regulation

CASE HUB NOTE—appeal lodged before the Court of Justice in Case C- 376/20 P ARCHIVED This archived case hub records the position as at the judgment of 28 May 2020 and is no longer maintained. For more detail, see the timeline, commentary and related cases. An appeal was lodged before the Court of Justice in Case C‑376/20 P. Case facts Outline Appeal before the General Court against the European Commission’s 2016 decision to block the proposed acquisition of Telefónica Europe plc by Hutchison 3G UK Investments Limited, taken under the EU Merger Regulation (Case M.7612). Latest development On 28 May 2020, the General Court handed down its judgment, upholding the action and annulling the Commission’s prohibition decision. The court set aside the prohibition. The Commission’s analysis of unilateral (non-coordinated) effects contained multiple errors of law and appraisal and did not show, to a sufficiently high degree of probability, that prices would rise markedly. The Commission did not establish that the transaction’s...

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PRACTICE NOTES
UK CMA merger control: Taboola/Outbrain—content recommendation to publishers; Phase 2 referral for unilateral effects; investigation cancelled after deal abandoned (Sept 2020); contrasted with US and German clearances

CASE HUB ARCHIVED –this archived case hub reflects the position at the date of the cancellation of the investigation on 14 September 2020 after the abandonment of the transaction; it is no longer maintained. See further, timeline. Case facts Outline UK merger investigation concerning the anticipated acquisition by Taboola.com Ltd of Outbrain, Inc. Both parties supply content recommendation to publishers, including prominent UK news sites. Latest developments On 23 September 2020, the CMA published a notice (dated 22 September 2020) formally cancelling its phase 2 investigation after the parties chose to abandon the proposed transaction. Parties Taboola.com Ltd (Taboola): Taboola provides digital advertising, notably content recommendation via a platform on publishers’ webpages that displays ads for external content under headings such as ‘Content You May Like’, ‘Recommended for You’ or ‘Around the Web’. Its customers include advertisers (individual firms, media agencies and digital advertising service providers), publishers, digital media platforms and readers of publishers’ websites. Outbrain, Inc (Outbrain): Outbrain is...

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PRACTICE NOTES
EU Merger Control under the EUMR: SIEC Test including CK Telecoms 2023, 2024 Market Definition, Horizontal/Non‑Horizontal Effects, Buyer Power, Efficiencies, Failing Firm, Ancillary Restraints and Joint Ventures

This Practice Note explains how the European Commission (the Commission) undertakes the substantive appraisal of mergers under the EU Merger Regulation (EUMR). Where a deal falls within the EUMR, the Commission must decide whether the concentration is compatible with the single market. Under the EUMR, any concentration that brings about a significant impediment to effective competition (SIEC) in the internal market, or a substantial part of it, in particular through the creation or strengthening of a dominant position, must be declared incompatible with the single market. By contrast, a concentration that does not lead to a SIEC in the internal market, or in a substantial part of it, must be cleared (ie deemed compatible with the single market). The SIEC test The SIEC test was introduced into EU competition law to close a gap identified by the European Courts when assessing the Commission’s attempts to address non‑coordinated effects in oligopolistic markets that at the same time did not trigger either single‑firm or collective dominance (which had originally limited...

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