What Is Abuse of a Dominant Position? Definition, Tests and Leading Cases

Abuse of a dominant position is the branch of competition law that disciplines powerful firms’ unilateral conduct — no agreement, no merger, just one company’s own commercial practices. It is also the branch where lawful hard competition and illegal exclusion look most alike, which makes it the most litigated boundary in the field. This guide sets out who counts as dominant, what conduct crosses the line, how the EU, US and Türkiye differ, and what the leading cases teach — opening the dominance pillar of our Global Competition & Antitrust hub.

What does “dominance” legally mean?

Dominance is the power to act independently of competitive constraint — to raise prices, cut quality or exclude without being punished by customers switching. Market share is the entry point, not the answer: EU case law presumes dominance at 50% absent contrary evidence, treats 40–50% as a serious candidate depending on structure, and has found dominance below 40% only rarely. US monopolization law typically wants 60–70%+ for monopoly power; Türkiye follows the EU pattern.

The share is then stress-tested against the real constraints: entry barriers (scale, network effects, switching costs, regulation, data), rivals’ ability to expand, countervailing buyer power, and the durability of the position over time. Digital markets have added new proxies — gatekeeping position, ecosystem lock-in, data accumulation — and the possibility of dominance in zero-price markets, where power shows in degraded privacy or attention terms rather than price. Two structural notes matter in practice: dominance can exist in narrow markets (spare parts for one brand, a single airport’s ground services), and collective dominance of a tight oligopoly is recognised in EU and Turkish law, though sparingly applied.

What separates abuse from competition on the merits?

The organising test: does the conduct win customers through better products, prices and service — or through raising rivals’ costs, foreclosing their access to customers and inputs, or exploiting captive counterparties? Competition on the merits may lawfully devastate rivals; exclusionary methods may not, even when dressed in commercial clothing.

Modern EU law — consolidated by the Court of Justice’s post-Intel jurisprudence and the Commission’s Article 102 guidance work — runs an effects-oriented analysis: capability of foreclosure assessed against the “as-efficient competitor” benchmark where pricing is at issue, actual context and evidence over form, and a genuine (rarely successful) efficiency defence. US Section 2 asks whether conduct is “exclusionary” beyond competition on the merits, with a stronger presumption in favour of unilateral freedom — notably the right to choose one’s counterparties. Türkiye’s Article 6 practice tracks the EU closely, including the effects turn in recent Board decisions and court judgments. Across all three, intent evidence — the emails announcing plans to “kill” a rival — never suffices alone but colours everything.

What are the main exclusionary abuse categories?

Five families recur. Exclusive dealing and loyalty rebates: locking customers or distributors into the incumbent through obligations or retroactive discount structures — the Intel battleground, covered in depth in our rebates and tying guide. Tying and bundling: leveraging the must-have product to move the contested one (Microsoft’s media player, Android’s app suite, Teams-Office — the case Microsoft settled with commitments after a formal EU probe).

Predation and margin squeeze: pricing below cost to eliminate, or squeezing downstream rivals between wholesale and retail prices — the tests are in our pricing-abuse guide. Refusal to supply and access denial: withholding essential inputs, interoperability or infrastructure — the essential-facilities doctrine. Self-preferencing and discrimination: a vertically integrated gatekeeper favouring its own downstream services, the theory Google Shopping made canonical and the DMA converted into a standing rule. Türkiye’s docket features every family — from Google decisions to sahibinden.com (excessive pricing) and food-delivery and marketplace cases (most-favoured-nation clauses and self-preferencing under the amended framework).

What is exploitative abuse — and why is it controversial?

Exploitation targets the dominant firm’s own counterparties: excessive prices bearing no reasonable relation to economic value (United Brands test), unfair trading conditions, and discriminatory terms placing equivalent partners at competitive disadvantage. The EU and Türkiye prosecute it — pharmaceutical price-gouging cases (Aspen’s commitments cutting cancer-drug prices), collecting-society tariffs, and the German Facebook decision treating data-extraction terms as exploitative all illustrate the reach; the US essentially does not, trusting entry to erode monopoly prices.

The controversy is institutional: price regulation by competition authority risks arbitrariness and chills investment, so enforcers reserve exploitation cases for entrenched positions with no self-correction prospect — patent-protected drugs, natural-monopoly infrastructure, standard essential patents. For businesses dealing with dominant suppliers, however, exploitative-abuse complaints are an underused lever: Turkish and EU authorities accept and pursue them, and the threat alone rebalances negotiations more often than the public record shows.

How do the EU, US and Türkiye differ in practice?

Threshold and theory. The EU intervenes from lower shares, recognises exploitation, and — despite the effects turn — retains categories where capability is readily presumed. The US demands more: higher power thresholds, proof of harm to competition (not competitors), no excessive-pricing doctrine, and judicial solicitude for unilateral dealing choices (Trinko). The result: conduct condemned in Brussels is routinely lawful in Washington — the same asymmetry visible in the Apple docket, where identical App Store rules lost under Article 102 and survived Section 2.

Türkiye enforces Article 6 on the EU model with local intensity: the Rekabet Kurulu runs an active unilateral-conduct docket across platforms, pharmaceuticals, energy, ports and retail, applies interim measures (used against Meta in the Threads case, with daily fines for non-compliance), and increasingly writes conduct remedies with monitoring. For multinationals the planning rule is to design conduct for the strictest applicable regime touching real revenues — usually the EU and Türkiye together — rather than litigating three different standards after the fact.

What are the consequences of an abuse finding?

Fines to 10% of worldwide group turnover in the EU and Türkiye, structural or behavioural remedies, and — increasingly consequential — obligations to deal: supply resumed, interoperability opened, terms equalised, with trustees monitoring. Private damages follow the public finding (competitors’ lost-profit claims, customers’ overcharge claims), and in platform markets the remedial architecture can reshape the product itself, as Google’s remedy screens and Apple’s DMA re-engineering show.

The less quantifiable consequence is the supervision era that follows: a found abuser negotiates every subsequent product change against regulator attention, and repeat findings escalate to recidivist uplifts and structural talk — the trajectory traced in our breakups analysis. Avoiding the first finding is therefore worth disproportionate investment, which is the practical case for the counselling patterns in this pillar’s remaining guides.

How do abuse investigations actually unfold?

Typically complaint-driven: a competitor, customer or supplier files a documented grievance; the authority tests it with information requests, sometimes a dawn raid, and market questionnaires. Interim measures — reactivated in EU practice (Broadcom) and used assertively by Türkiye’s Board — can freeze conduct years before a final decision. The defence phases mirror cartel procedure (statement of objections, access to file, oral hearing), but with economics at the centre: foreclosure analyses, AEC computations and market studies dominate the record.

Commitment decisions resolve a large share of unilateral-conduct cases: binding behavioural promises without an infringement finding or fine — faster for the authority, damages-safer for the company (no finding for claimants to ride). The strategic fork between fighting and committing is among the most consequential a dominant firm faces: commitments buy certainty and supervision; contesting buys the chance of vindication at the price of a decade and a possible fine — the Intel and Google trajectories in miniature.

Which sectors face the heaviest unilateral-conduct scrutiny now?

Digital platforms lead everywhere, but the docket is broader than headlines suggest: pharmaceuticals (pay-for-delay follow-ons, excessive pricing of off-patent drugs, supply squeezes), energy (network access, capacity withholding), ports, airports and logistics bottlenecks, payment systems, and agriculture-adjacent processing where regional monopsonies exploit suppliers. Türkiye adds fast-moving consumer goods distribution and marketplace platforms as standing priorities, with sector inquiries (e-marketplaces, fintech) feeding cases.

The screening pattern is structural: wherever a vertically integrated firm controls a stage rivals must pass through, expect authority attention within the planning horizon — and expect complainants, since customers and dependent businesses now file sophisticated, economist-supported complaints as a negotiating instrument. Reading your own sector’s inquiry reports is the cheapest regulatory intelligence available: authorities announce their theories years before the first decision lands.

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