Self-preferencing complaint under the DMA: what it means for marketplace sellers

TL;DRA self-preferencing complaint under the Digital Markets Act (DMA) is a formal challenge to a gatekeeper platform – such as Amazon – for ranking or displaying its own products and services more favorably than those of third-party sellers, without objective justification. For sellers on Amazon ES and across the EU, the DMA creates a concrete legal basis to contest that conduct, whether through the European Commission, a national competition authority, or through the platform's own internal complaint-handling system. The realistic options, the procedural sequence, and the trade-offs involved are what this analysis sets out to explain.

This page covers: what self-preferencing means in practice on Amazon ES; how the DMA's prohibition operates and who enforces it; the procedural path a seller can realistically take; the commercial trade-offs; and what to do if the path forward is unclear.

What self-preferencing actually means for a seller on Amazon ES

Self-preferencing, in the DMA context, occurs when a gatekeeper platform favors its own downstream products or services over comparable third-party offerings in ways that are not explained by objective criteria. On Amazon ES, the most visible forms are search-ranking advantages for Amazon's own private-label products, placement of Amazon's own listings at the top of organic results, and the systematic use of data derived from third-party seller activity to inform Amazon's own inventory and pricing decisions.

For a seller running an established brand on Amazon ES, the commercial impact is direct. If Amazon-owned products or Amazon-affiliated listings consistently appear above yours for the same search terms, the search placement gap costs you visibility, conversion, and – ultimately – revenue. The damage is not always dramatic enough to register as a single "event," which is part of what makes it harder to address than a formal suspension notice. It accumulates across thousands of impressions per day.

The DMA's self-preferencing prohibition – under its gatekeeper obligations for core platform services – requires Amazon, as a designated Very Large Online Platform and gatekeeper, to treat third-party sellers' products at least as favorably as its own in ranking and indexing. This is not a vague aspiration; it is an enforceable obligation backed by the threat of significant fines and, in repeat-infringement cases, structural remedies. In matters we handle, sellers often underestimate how directly this rule speaks to their commercial position.

What the rule does not do, however, is guarantee any particular ranking outcome for your listings. It prohibits unjustified differentiation in favor of Amazon's own offerings. The practical question – whether a given ranking pattern crosses that line – requires an analysis of how the algorithm treats comparable listings, what justifications Amazon offers, and how the Commission or a national authority is likely to assess the evidence.

How does the DMA's self-preferencing prohibition actually operate?

The Digital Markets Act prohibits gatekeepers from treating their own products and services more favorably in ranking, indexing, crawling, or display than comparable third-party offerings in the same category. The obligation is not conditional on proof of market harm in the traditional competition-law sense; it is a per-se behavioral rule applied to designated gatekeepers. That is a meaningful difference from a standard abuse-of-dominance claim under EU competition law.

Amazon's designation as a gatekeeper covers its online intermediation services – meaning the marketplace itself, including Amazon ES. Once designated, Amazon is required to put in place technical and contractual arrangements that prevent self-preferencing. The European Commission is the primary enforcement authority. It has broad powers: to investigate, to impose interim measures, to fine, and ultimately to order structural changes. National competition authorities in EU member states – including the Spanish Comisión Nacional de los Mercados y la Competencia (CNMC) – may also act in parallel or in coordination with the Commission, though the DMA's primary enforcement track runs through Brussels.

For an individual seller, a complaint to the Commission is not a straightforward "submit a form and get a result" exercise. The Commission prioritizes cases of broad systemic significance. A complaint from a single seller will only move the needle if it either illustrates a pattern the Commission is already investigating or contributes to a coordinated filing with other affected sellers. That does not mean individual complaints are worthless – they feed the evidentiary record – but a seller acting alone should understand that timeline expectations are long and outcomes are not within the seller's control once the complaint is filed.

Alongside the Commission track, the DMA's internal complaint-handling requirements create a more immediately useful tool for many sellers. Amazon is required under the DMA to maintain an internal complaint-handling system that processes complaints about its compliance with gatekeeper obligations, including self-preferencing. That system must be accessible, free of charge, and must produce a reasoned outcome. The Platform-to-Business (P2B) Regulation provides a complementary layer, requiring transparent ranking parameters and giving sellers the right to understand why their products rank where they do. We regularly see cases where the P2B ranking-parameter disclosure, combined with a formal DMA internal complaint, creates pressure that a standard Seller Central appeal process does not.

What is the realistic procedural path for an Amazon ES seller?

A seller facing a self-preferencing issue on Amazon ES has three realistic procedural routes, which are not mutually exclusive and are often run in parallel.

The first route is the DMA's internal complaint-handling mechanism. Amazon operates this at the platform level, distinct from ordinary Seller Central support. A formal complaint through this channel invokes Amazon's obligation to investigate and respond with reasons. The quality and pace of that response varies, but the formal record created by the filing matters – both for any subsequent Commission complaint and for potential civil litigation. The internal complaint should identify the specific ranking or display conduct complained of, reference the DMA's gatekeeper obligations, and request Amazon's statement of reasons for the differential treatment. Generic complaints produce generic responses.

The second route is a complaint to the European Commission or, where the conduct also implicates national competition law, a parallel complaint to the CNMC. The Commission has an online complaint mechanism for DMA matters. As noted above, individual complaints are unlikely to drive near-term enforcement action on their own, but they are part of how the Commission's investigation priorities are shaped. A well-documented complaint – with concrete data on ranking positions, search terms, the seller's product versus Amazon's comparable product, and timing – is more useful to the Commission than a general grievance. The P2B Regulation's right to obtain ranking parameter explanations is a useful evidential tool before filing at this stage.

The third route is civil litigation in a competent EU court, seeking an injunction or damages on the basis of the DMA's directly effective obligations. Civil enforcement of the DMA is an evolving area. National courts in several EU member states have shown willingness to apply the DMA's rules directly in private litigation, particularly where interim relief is sought. For most individual Amazon ES sellers, the cost-benefit calculation for standalone civil litigation is challenging unless the lost revenue is significant. Where multiple sellers have been affected by the same ranking conduct, a coordinated approach changes the calculus.

In matters we handle involving EU marketplace suspension or delisting alongside a self-preferencing complaint, we typically map all three routes at the outset and advise on sequencing. The internal complaint creates the fastest formal record. The Commission complaint adds regulatory pressure. Civil litigation provides the only route to a binding judicial order or damages award. Running them in parallel, where that is proportionate to the commercial loss involved, is often the right structure.

A clothing and accessories brand selling on Amazon ES came to us in winter 2026 after observing a sustained decline in organic search placement that tracked the launch of an Amazon private-label competitor in the same category. We assessed the ranking data, prepared a formal DMA internal complaint with detailed product comparisons and search-term data, and lodged a P2B ranking-parameter information request in parallel. The combination produced a formal written response from Amazon's compliance function and opened a documented record that the seller had not previously had. The situation remains live – which is realistic for DMA enforcement timelines – but the seller now has a documented evidentiary position.

What are the seller's real decision points and trade-offs?

The first decision is whether to file formally at all. Some sellers conclude that the commercial relationship with Amazon makes a formal complaint strategically unwise, at least as a first step. That concern is understandable but often overstated. The DMA explicitly prohibits retaliation by gatekeepers against complainants. Whether that prohibition deters every form of platform pushback is a separate question, but the legal baseline is clear: Amazon cannot suspend, delist, or otherwise penalize a seller for exercising DMA rights.

Is a formal complaint the right move in every case? Not always. Where the self-preferencing conduct is marginal, the evidentiary record is thin, or the seller's sales on Amazon ES are a minor part of overall revenue, the cost of a formal complaint process may outweigh the expected benefit. This is a genuine trade-off, not a reason to avoid the law. We work with sellers to assess proportionality before committing to a procedural path.

The second decision is sequencing. The internal complaint mechanism under the DMA should almost always come first – it is low cost, creates a formal record, and may produce a resolution or explanation that removes the need for further action. The Commission complaint and any civil litigation then build on that record. Filing at the Commission before exhausting the internal mechanism can be done, but the Commission typically expects sellers to have engaged with the internal process first.

The third decision concerns the evidence standard. A self-preferencing complaint without concrete comparative data on ranking positions, product comparability, and timing is weak. The DMA does not require proof of harm in the competition-law sense, but the Commission and Amazon's compliance function will both ask: what specifically are you comparing, over what period, on what search terms? Building that dataset before filing is work, but it is the work that makes the difference between a complaint that advances and one that is noted and filed. The P2B Regulation's ranking-parameter information right is a useful tool for building that case without resorting to reverse-engineering the algorithm.

The fourth decision – one we often see sellers miss – is whether the self-preferencing issue is connected to an eu marketplace suspension or a separate Account Health problem. On Amazon ES, it is not uncommon for a seller whose listings have been systematically de-ranked to eventually face a performance-related deactivation notice as well, because suppressed visibility reduces sales velocity, which can trigger Amazon's internal performance metrics. The two issues have different procedural paths, and conflating them in a single filing weakens both. Separating them, and addressing the deactivation through the reinstatement route while the DMA complaint addresses the ranking conduct, is usually the stronger structure.

For context on how EU marketplace suspensions work procedurally across platforms and jurisdictions, our complete guide to EU marketplace regulation for sellers covers the broader framework and the DSA seller rights that apply across the platforms we work on. For sellers active on Amazon DE as well as Amazon ES, our analysis of how to handle a German marketplace suspension on Amazon DE addresses the parallel enforcement structures that apply in Germany, including the Bundeskartellamt's proceedings under its own national competition rules. Sellers with cross-border UK exposure should also review UK marketplace suspension after Brexit: what changed and what to do, since the UK is no longer covered by the DMA and the applicable rules diverged materially after Brexit.

Where does the myth that EU sellers have no leverage come from – and why is it wrong?

The belief that a suspension or delisting under EU rules is effectively final, and that EU sellers lack meaningful recourse against a platform like Amazon, is one of the most persistent misconceptions we encounter. It has a plausible origin: pre-DMA, pre-DSA, the formal tools available to sellers in EU-based marketplace disputes were limited. A seller's main options were a standard Seller Central appeal, a complaint to a national consumer authority that rarely prioritized B2B marketplace disputes, or expensive civil litigation.

That picture changed materially when the DMA and the Digital Services Act (DSA) came into full force. The DSA's statement-of-reasons requirement, internal complaint-handling system, and seller rights against arbitrary restrictions create enforceable procedural entitlements. The DMA's gatekeeper obligations – including the self-preferencing prohibition – go further, imposing substantive behavioral rules that are enforceable by the Commission, national authorities, and private litigants. The P2B Regulation, which predates both, requires ranking transparency and prohibits certain forms of differentiated treatment without explanation.

Together, these instruments give an EU seller a genuinely different toolkit than existed five years ago. The toolkit requires skill to use – the complaint must be well-constructed, the evidence must be specific, the procedural sequence must be chosen deliberately – but the leverage is real. In matters we handle, we regularly see Amazon respond differently to a formally constructed DMA or DSA complaint than to a generic appeal. The formal structure of the complaint, and the documented record it creates, shifts the dynamic.

The myth also underestimates the DMA's retaliation prohibition. A seller who files a DMA complaint is legally protected from adverse action by the gatekeeper in response to that complaint. That protection is not a guarantee that Amazon will never act adversely – enforcement of the retaliation prohibition is itself a process – but it is a meaningful baseline that did not exist in the pre-DMA period.

A consumer-electronics accessories seller on Amazon ES (spring 2026) came to us convinced that its account was effectively lost after a combination of search-ranking suppression and a subsequent delisting notice. We separated the two issues: the delisting was addressed through a DSA-structured internal complaint with a formal statement of reasons, and the ranking conduct was addressed through a DMA self-preferencing complaint. Neither produced an immediate reversal, but both produced documented formal responses and kept the seller's procedural options open. The seller's listings were restored within several weeks of the DSA complaint being filed.

What should a seller on Amazon ES do right now?

If you are an Amazon ES seller who suspects self-preferencing conduct is affecting your search placement, the immediate priorities are: document the ranking data now, before the evidence degrades; request Amazon's ranking parameter explanations under the P2B Regulation; and assess whether the ranking issue is linked to any account health or deactivation notice, which requires separate handling.

Documentation is the most time-sensitive step. Search ranking data is not retrospectively retrievable in the form needed for a formal complaint. If you can demonstrate what your ranking was on specific search terms, compared to comparable Amazon-own products, over a defined period – and if you can show the differential is systematic rather than incidental – you have the foundation for a substantive complaint. Without that data, the complaint will be treated as a general grievance.

If a first appeal or formal complaint has already come back with a generic rejection or no substantive response, a second read by a specialist can identify whether the complaint was miscategorized, whether the evidence was insufficient, or whether a different procedural track is more appropriate. Many sellers who contact us after an initial rejection find that the problem was not the strength of their underlying position but the framing and evidence standard of the original filing.

To have a confidential review of your situation on Amazon ES – whether the issue is self-preferencing, a suspension, or a combination – email info@tutamenlaw.com. Fixed fees are quoted up front after a short review of your account position.

Related areas

• EU Marketplace Regulation – full practice overview for EU and UK marketplace sellers
• Amazon Account Reinstatement – appeal and Plan of Action work for suspended accounts
• Arbitration and Disputes – Notice of Dispute, pre-arbitration demand, and AAA arbitration

Frequently asked questions about self-preferencing complaints under the DMA

How long does resolving a self-preferencing complaint under the DMA usually take on Amazon ES?

There is no single timeline, because the answer depends entirely on which procedural track is used. An internal complaint under the DMA's complaint-handling mechanism can produce a formal response within several weeks to a few months. A European Commission investigation operates on a much longer cycle – formal investigations of this kind typically run over a period of years before a final decision. Civil litigation in a Spanish court for interim relief can be faster where the evidentiary threshold is met, but varies by court and case complexity. In matters we handle, we map the realistic timeline for each track before advising which to prioritize, and we generally run the internal complaint first because it is the fastest to produce a documented formal record.

What are the main risks if I handle a self-preferencing complaint under the DMA alone?

The primary risk is a weak evidentiary record that closes off better options later. A generic complaint – "Amazon is ranking its own products above mine" – will receive a generic response. The DMA's obligations are specific, and so is the analysis required to demonstrate a breach. A second risk is conflating the self-preferencing complaint with an account health or deactivation issue, which can weaken both filings. A third risk is missing the P2B Regulation's ranking-parameter information right, which is often the most useful pre-complaint tool and which sellers frequently overlook. None of these risks is insurmountable, but they are the reasons that sellers who file alone often find themselves with a documented complaint that has not advanced their position.

Do I need a lawyer for a self-preferencing complaint under the DMA?

Technically, no – a seller can file a DMA internal complaint or a Commission complaint without legal representation. In practice, the quality of the complaint determines whether it produces a substantive outcome. An attorney experienced in EU marketplace regulation can assess whether the conduct crosses the DMA's threshold, structure the evidentiary file, select the right procedural track, and draft a complaint that Amazon's or the Commission's compliance function has to engage with substantively. For complaints where the commercial loss is significant or the seller is simultaneously managing a suspension or delisting, attorney-led handling is materially more effective. For straightforward ranking inquiries where the seller wants to understand their rights before deciding on next steps, a short review call may be all that is needed at the outset.

About Tutamen

Tutamen is an independent law firm for online marketplace sellers. We represent Amazon, Walmart, Etsy and eBay sellers in account deactivations, frozen-funds recovery, intellectual-property disputes, arbitration and Notices of Dispute, and US federal Schedule A defense, plus EU marketplace regulation. Our work is attorney-led and confidential, with fees quoted up front. We act for founders, brand owners and in-house teams who need a specialist for a marketplace dispute. Our practice on EU marketplace regulation covers the DMA, the DSA, the P2B Regulation, and national competition proceedings, with all work handled by attorneys and all advice treated as confidential from the first contact. To discuss your situation, email info@tutamenlaw.com.

Disclaimer: This article is general information, not legal advice, and does not create an attorney-client relationship. Marketplace policies and the law change, and every account and case is different. For advice on your situation, contact Tutamen at info@tutamenlaw.com.

Page authored by Dmitri Aronov, Partner, EU Marketplace Regulation, Tutamen.