What to know about self-preferencing complaint under the DMA

TL;DRA self-preferencing complaint under the Digital Markets Act (DMA) is a formal challenge asserting that Amazon – designated as a gatekeeper under EU law – ranked, displayed, or otherwise favored its own products or services over those of third-party sellers on its platform. On Amazon ES and other EU surfaces, the DMA gives the European Commission direct enforcement authority, and parallel complaint paths exist at the national level. Whether your route is a Commission complaint, a national-competition-authority filing, or an internal platform dispute under the Platform-to-Business (P2B) Regulation depends on the specific conduct, your evidence, and the urgency of the commercial harm.

The page below answers the questions sellers on Amazon ES most often bring to us the day they realize that a self-preferencing issue is costing them real revenue. Each section opens with the direct answer, then gives the procedural and strategic depth you need to decide on a next step. If you want a read on your specific situation before committing to any path, email info@tutamenlaw.com.

What is self-preferencing under the DMA, and how does it appear on Amazon ES?

Self-preferencing under the DMA refers to a gatekeeper treating its own products, services, or data more favorably than those of competing third parties on the same platform – in ways that distort fair competition. Amazon has been designated as a gatekeeper under the DMA for its online intermediation services, and the DMA's obligations are directly binding on it across all EU surfaces, including Amazon ES.

In practice, self-preferencing on Amazon ES can take several forms. The most common pattern in matters we handle is ranking manipulation: Amazon's own-brand or Amazon-retail-fulfilled listings appearing systematically above comparable third-party offers despite equivalent or inferior relevance signals. A second pattern is the "Buy Box" or featured-offer display: where the platform algorithm consistently selects Amazon's own offer for the featured position, reducing organic visibility for sellers who match or beat Amazon's price and shipping terms.

A third, subtler form involves data asymmetry. The DMA prohibits a gatekeeper from using non-public seller data – the data you generate when selling on the platform – to gain an advantage for its own competing activities. If Amazon uses your conversion data, your price-testing results, or your category sales trends to inform the positioning of an Amazon-label competitor, that is the kind of conduct the DMA addresses.

The self-preferencing prohibition under the DMA is not a theoretical overlay. It is a binding legal obligation with the European Commission as the primary enforcer and significant penalty exposure for the gatekeeper. That enforcement backdrop matters when you are assessing whether a complaint is worth making and what it can realistically achieve for you. Our EU marketplace regulation complete guide for sellers sets out the full DMA/DSA/P2B architecture for context.

What procedural paths exist for a DMA self-preferencing complaint on Amazon ES?

A seller on Amazon ES who believes Amazon is engaging in prohibited self-preferencing has three main procedural routes, and they are not mutually exclusive.

First, a complaint to the European Commission. The Commission is the exclusive enforcer of the DMA's gatekeeper obligations for the largest designated services. You can file a formal complaint with the Commission's Directorate-General for Competition (DG COMP) identifying the conduct, the affected market, and the harm. The Commission may open a formal investigation on its own initiative or following a complaint. Commission proceedings tend to be slow by the standards of a seller who is losing revenue now – they run over months to years. Their value is structural: a Commission finding changes the platform's behavior across the EU, not just for your listing.

Second, a complaint to a national competition authority (NCA). The DMA's enforcement architecture designates the Commission as the primary body, but national authorities retain a role in related competition-law proceedings under Article 102 TFEU, which overlaps significantly with self-preferencing. In Spain, the relevant body is the Comisión Nacional de los Mercados y la Competencia (CNMC). NCA proceedings can move faster than Commission proceedings in some circumstances, particularly where national market effects are clearly documented.

Third, the internal complaint mechanism under the P2B Regulation. Amazon is required under the Platform-to-Business Regulation to maintain an internal complaint-handling system for business users. If the self-preferencing manifests as a ranking or visibility issue that affects your specific listings, a formal internal complaint – distinct from a standard Seller Central support ticket – triggers procedural obligations on Amazon's part. In matters we handle, a well-constructed P2B internal complaint can produce a substantive response faster than any regulatory filing, and it creates a documented record that supports later steps.

The realistic path for most sellers on Amazon ES combines an escalated P2B internal complaint with a parallel Commission or CNMC filing, depending on the scale and nature of the conduct. The decision turns on how clearly the self-preferencing can be documented, how significant the commercial harm is, and whether you need an immediate remedy or a structural outcome. For sellers who are also facing an EU marketplace suspension tied to a related dispute, the interaction between the DMA complaint path and the suspension appeal path requires careful sequencing – see our analysis of how to handle a marketplace suspension for the procedural discipline that applies across surfaces.

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

Timelines vary significantly by route, and no honest answer involves a single number. A Commission investigation into gatekeeper non-compliance can run for a year or more before a formal finding; interim measures are possible but require the Commission to act, which adds its own time. An NCA proceeding under national competition law has its own docket and priority constraints. The internal P2B complaint mechanism – if properly invoked with a specific documented grievance – can produce a first substantive response within weeks, though whether that response resolves the commercial harm is a separate question.

What the timeline depends on most, in our experience, is the quality of the evidence you can put in front of the relevant body on day one. A self-preferencing complaint that arrives with rank-tracking data, price-comparison screenshots, and a clear articulation of the affected SKUs and the commercial loss moves faster and generates better responses than a general complaint about "unfair treatment." The evidentiary threshold for a regulatory complaint is different from a Seller Central support ticket – it is closer to a legal pleading than a helpdesk submission.

Sellers on Amazon ES should also factor in that the DMA is still in an early enforcement phase. The Commission is developing its case-handling practice, and NCAs are calibrating their role. That means procedural timelines are not fully settled. What is clear is that doing nothing while losses accumulate is the worst timeline of all. The window to build a clean evidentiary record closes as platform behavior evolves and historical data ages out of retention systems.

What evidence do I need, and how do I build it?

Evidence is the controlling variable in a DMA self-preferencing complaint. Without it, a complaint is an allegation. With it, a complaint becomes a case that a regulator can act on.

The core evidence in most Amazon ES self-preferencing matters falls into four categories. First, ranking and visibility data: systematic documentation of your listing's search position compared to Amazon's own offers for the same search terms, over a meaningful time period. A single screenshot is not evidence. A dataset covering weeks or months, showing a consistent pattern, is the beginning of a case.

Second, Buy Box or featured-offer data: records of which offer held the featured position, at what price and fulfillment terms, and whether your competing offer was objectively equivalent or superior on the metrics Amazon states it uses. The DMA's self-preferencing prohibition does not require you to prove intent; it requires demonstrating that Amazon's own service received treatment that third-party services in an equivalent position did not receive.

Third, data-use documentation: any evidence that conduct by Amazon on the retail or private-label side correlates with data generated by your seller account. This is the hardest category to document because the data use occurs inside Amazon's systems. What you can document externally is the timing correlation between your sales activity and competitive behavior by Amazon's own brands in your category.

Fourth, commercial-loss quantification: revenue, conversion, and traffic data from your Seller Central account showing the measurable impact of the conduct on your business. Regulators respond to documented harm, not hypothetical harm.

In matters we handle, we work with sellers to build this evidence base before any filing, so that the complaint goes in fully supported rather than being weakened by a regulatory response asking for substantiation. The P2B Regulation also supports this approach: building the statement-of-reasons and internal-complaint case against the documented record is the first step in the procedural sequence we use. For a broader view of how EU and UK platforms interact on these issues, the analysis at UK marketplace suspension after Brexit – what it means for marketplace sellers shows why evidentiary discipline matters across jurisdictions.

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

The primary risk is procedural irreversibility: a complaint filed without adequate evidence or proper legal framing can be dismissed or closed without substantive review, and a dismissed complaint creates a record that a subsequent better-evidenced complaint has to overcome. Regulators do not treat a re-filed complaint as a clean slate.

A second significant risk is misrouting. Sellers who file a DMA complaint with the wrong body – for example, filing a competition-law claim as a P2B internal complaint, or filing a P2B complaint with the Commission rather than through Amazon's internal mechanism – lose time and create a paper trail that may complicate the correct filing. The DMA, the P2B Regulation, and national competition law address overlapping conduct through distinct channels. Choosing the wrong channel at the outset is a recoverable mistake, but it costs time you may not have if the commercial harm is ongoing.

Third, Amazon's internal complaint systems are designed to receive and respond to complaints on the platform's own terms. A seller without legal support tends to frame the complaint in the language of Seller Central policy rather than the language of the DMA obligation. That framing change matters: Amazon's obligations under the DMA are external legal obligations, not internal policy choices, and the response it owes to a complaint framed in DMA terms is different from the response it owes to a support ticket.

There is a broader myth worth addressing directly: that EU sellers have no real leverage once a large platform decides to act against their interests. That is not accurate. The DMA was designed specifically to create structural leverage for business users against gatekeepers. The Commission has interim-measure powers, NCA proceedings have injunctive remedies, and the P2B Regulation imposes specific obligations with redress mechanisms. The leverage exists. The question is whether it is used correctly.

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

You are not legally required to use a lawyer to file a DMA complaint, but the practical value of legal support is high – and it increases with the size of the commercial harm at stake. Here is the honest assessment of where legal support makes a difference and where it may not.

For a P2B internal complaint about a specific listing or ranking issue where the evidence is clear and the remedy sought is narrow, a well-organized self-filed complaint can be effective. The P2B mechanism was designed to be accessible to business users without specialist legal knowledge, and the platform is required to engage with it substantively.

For a Commission or NCA filing alleging systematic self-preferencing conduct – where the claim requires evidence of a consistent pattern, legal framing under the DMA's specific obligations, and engagement with regulatory procedure – legal support is not a luxury. The standard a regulator applies to a formal complaint is a legal standard. Meeting it without legal guidance means either underbuilding the case or overstating it, and both paths produce weak outcomes.

The middle ground is a scoping engagement: a fixed-fee review of your situation, the evidence you have, and the realistic options. In our practice, that is typically how we start with an Amazon ES seller on a DMA matter. It gives you a clear-eyed assessment of whether a complaint is worth making, which route has the best cost-to-outcome ratio for your business, and what evidence you need to build first. The assessment is attorney-led, confidential, and priced so that you do not have to commit to a full engagement before you know what you are working with.

A home-goods seller on Amazon ES (winter 2026) came to us after noticing a persistent ranking gap between their top-volume SKUs and an Amazon-private-label competitor in the same subcategory. We reviewed the rank-tracking data, mapped the Buy Box history against pricing parity, and built a statement of reasons for an escalated P2B internal complaint framed explicitly around the DMA's self-preferencing obligation. The platform's internal compliance team engaged at a substantive level within several weeks and the seller's listings regained consistent featured-offer positioning in the affected category. The Commission filing remained open as a contingency.

If a first attempt at an internal complaint or a support escalation has already come back with a generic response, that is not a closed door. In matters we handle, a re-framed complaint built on the specific DMA obligation rather than Seller Central policy language often generates a materially different response. To discuss whether that is the right next step for your situation, contact us at info@tutamenlaw.com.

Related areas

• EU Marketplace Regulation – Complete Guide for Sellers – the full DMA, DSA, and P2B framework explained for operators
• EU Marketplace Regulation Practice – Tutamen's practice hub for EU and UK platform disputes

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?

Timelines depend on the route chosen and the quality of evidence submitted. An escalated P2B internal complaint, properly framed, can produce a substantive platform response within weeks. A formal Commission investigation into gatekeeper conduct typically runs over months to years, though interim measures can shorten the remedial timeline. NCA proceedings under national competition law sit between those poles. The single biggest determinant of timeline is evidentiary completeness on day one: complaints that arrive well-documented move faster at every level of the process.

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

The most serious risk is procedural: a complaint filed without adequate legal framing or evidence can be dismissed or closed, and re-filing faces a higher burden. A related risk is misrouting – filing the complaint through the wrong channel costs time and creates a paper trail that complicates the correct filing later. Sellers also commonly frame complaints in Seller Central policy language rather than DMA obligation language; that framing gap typically produces a weaker platform response. Legal support at the drafting stage addresses all three risks before the complaint goes in.

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

Not for every step. A narrow P2B internal complaint about a specific listing can be filed without legal support and still be effective. For a Commission or NCA filing – where the claim must meet a formal legal standard and the evidence must be structured as a case – legal guidance is a practical necessity, not a formality. The most cost-effective starting point is a scoping engagement: a fixed-fee review that tells you which route fits your situation, what evidence you need, and what the realistic options are before you commit to a full filing.

Can I file a DMA self-preferencing complaint and still keep selling on Amazon ES?

Yes. Filing a DMA complaint or a P2B internal complaint does not require you to stop selling or to disclose the complaint to Amazon in a way that would affect your account status. The DMA's retaliation provisions – prohibiting a gatekeeper from taking adverse action against business users who use the platform's complaint or regulatory-complaint channels – provide a legal protection here, though documenting the sequence of any account action relative to a complaint filing is prudent. If a suspension follows a complaint filing, the timing is relevant to a potential retaliation claim.

How does the DMA self-preferencing prohibition interact with Amazon's BSA and Seller Central policies?

Amazon's Business Solutions Agreement (BSA) and Seller Central policies are the internal contractual and operational rules between you and Amazon. The DMA's self-preferencing obligation is an external legal obligation that binds Amazon regardless of what its BSA says. Where the two conflict – for example, where a BSA policy implements a practice the DMA prohibits – the DMA prevails. That hierarchy matters practically: a complaint framed in BSA policy terms is limited by what the BSA says; a complaint framed in DMA terms engages obligations the platform cannot override by contract.

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. All engagements start with a scoping review so you know the realistic options before committing to a full matter. To discuss your situation, email info@tutamenlaw.com.

Byline: Dmitri Aronov – Partner, EU Marketplace Regulation, Tutamen.

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.