Affiliate Marketing Platform Dominance Risks in Europe

1. Meaning

An affiliate marketing platform connects advertisers or merchants with affiliates such as:

websites;

bloggers;

comparison sites;

influencers;

cashback platforms;

coupon websites;

mobile applications;

content creators;

price-comparison services.

A simplified structure is:

Advertiser/Merchant → Affiliate Network/Platform → Affiliate → Consumer → Click/Lead/Purchase → Commission

The platform may provide:

affiliate recruitment;

tracking links;

cookies and identifiers;

conversion tracking;

attribution;

commission calculation;

payment processing;

fraud detection;

ranking of affiliates;

advertiser access;

analytics.

A dominance problem can arise when a platform becomes an important intermediary between advertisers and affiliates and uses its position to disadvantage competing networks, affiliates or advertisers.

European competition law does not prohibit dominance itself. Article 102 TFEU prohibits abuse by a dominant undertaking, and the Commission considers market definition, market shares, barriers to entry, buyer power, resources and vertical integration when assessing dominance. (Competition Policy)

2. Main Affiliate-Marketing Dominance Risks

The principal risks include:

exclusive dealing;

self-preferencing;

tying and bundling;

discriminatory affiliate commissions;

preferential ranking;

control over attribution data;

restriction of competing tracking systems;

API and interoperability restrictions;

data accumulation;

raising rivals' costs;

platform access restrictions;

unfair contractual conditions;

retaliation against affiliates using competing networks;

leveraging from one market into another.

These risks become stronger when the same company operates several layers of the digital advertising ecosystem.

3. Vertical Integration

Suppose Company X operates:

an affiliate network;

an advertising exchange;

a search engine;

a browser;

an analytics platform;

a payment system.

It could potentially use information obtained at one level to benefit another service.

For example:

Affiliate network data

↓

Consumer conversion information

↓

Advertising targeting

↓

Ranking

↓

More traffic

↓

More affiliate transactions

This creates a potential data-feedback loop.

Vertical integration itself is not unlawful. The relevant question is whether the integrated undertaking uses its position to engage in abusive exclusionary conduct. The Commission expressly identifies vertical integration as one factor relevant to assessing dominance. (Competition Policy)

4. Affiliate Attribution as a Competitive Bottleneck

Affiliate platforms frequently control the mechanism that determines:

Which affiliate receives commission for a transaction?

For example:

Consumer sees Affiliate A's article
→ clicks Affiliate A
→ later clicks Affiliate B's coupon
→ purchases product.

Who receives the commission?

Possible models include:

first click;

last click;

multi-touch attribution;

time-decay;

position-based;

algorithmic attribution.

If a dominant platform controls the attribution system, it may have substantial influence over the economic rewards received by affiliates.

This makes attribution control a potential competitive bottleneck.

However, an unusual attribution methodology is not automatically an abuse. Evidence would be needed that the methodology forms part of exclusionary conduct and produces the legally relevant competitive effects.

5. Case Law

Case 1 — Google Shopping

Google and Alphabet v Commission

C-48/22 P, CJEU, 10 September 2024

This is one of the most important European digital-platform cases.

Google was found to have favoured its own comparison-shopping service in general search results over competing comparison-shopping services. The CJEU upheld the essential finding of abuse and the €2.4 billion fine. (curia)

Relevance to affiliate platforms

An affiliate platform may similarly operate a marketplace or ranking mechanism while also having its own competing services.

Potential examples could include:

its own affiliate publishers;

its own comparison service;

its own coupon service;

its own cashback service.

The Google Shopping principle is therefore relevant where a dominant platform uses control over an important intermediary or ranking mechanism to favour its own downstream service.

The exact legal analysis would depend on the specific conduct and competitive effects.

6. Case 2 — Google AdSense for Search

Google and Alphabet v Commission

T-334/19, General Court, 18 September 2024

Google's AdSense service provided advertising intermediation for websites.

The Commission had found abuses involving contractual restrictions imposed on publishers.

The General Court annulled the Commission's decision because of errors concerning, among other matters, the duration and market coverage of the relevant restrictions. (curia)

Relevance

Affiliate networks similarly depend on contracts with:

advertisers;

publishers;

affiliates.

The case demonstrates an important rule:

A competition authority must precisely establish the duration, coverage and competitive significance of contractual restrictions.

A dominant affiliate network cannot be found liable merely because it uses restrictive contracts. The authority must establish the relevant legal and economic elements.

7. Case 3 — Meta Platforms

Meta Platforms and Others

C-252/21, CJEU, 4 July 2023

The case concerned Meta's combination of Facebook data with information obtained from other services and third-party websites and applications.

The CJEU held that a competition authority may, in the context of an abuse-of-dominance investigation, examine whether data processing complies with the GDPR, while respecting the powers of the competent data-protection authorities. (curia)

Relevance to affiliate platforms

Affiliate platforms can accumulate:

click data;

purchase data;

customer identifiers;

browsing data;

affiliate-performance data;

advertiser data.

A dominant platform's ability to combine these datasets may potentially create an important competitive advantage.

The case therefore provides an important framework for analysing the relationship between:

data accumulation + dominance + competitive effects + privacy law.

8. Case 4 — Bronner

Oscar Bronner GmbH & Co. KG v Mediaprint

C-7/97, CJEU, 26 November 1998

Bronner is the classic EU authority concerning refusal of access to infrastructure.

The Court imposed demanding conditions before a refusal to supply/access could constitute abuse, including the importance of indispensability and the absence of viable alternatives.

Affiliate-platform relevance

Imagine a dominant affiliate platform controls a tracking system that affiliates allegedly need to compete.

A competing affiliate network might claim:

"We need access to the dominant platform's tracking infrastructure."

Bronner indicates that merely showing that access would make competition easier is insufficient.

The precise legal requirements concerning indispensability, elimination of effective competition and alternatives would need to be examined.

9. Case 5 — Deutsche Telekom

Deutsche Telekom AG v Commission

C-152/19 P, CJEU, 25 March 2021

The case involved exclusionary conduct and pricing/access conditions in telecommunications.

It is important for affiliate-platform analysis because the Court's case law distinguishes different types of exclusionary conduct rather than applying one universal test to every form of dominance abuse.

Affiliate relevance

Consider a dominant affiliate network charging:

affiliates one commission rate;

competing affiliate networks another;

advertisers different access fees;

independent tracking providers discriminatory access fees.

The economic and legal analysis would depend upon the precise conduct.

The key lesson is:

The correct economic test depends upon the actual theory of abuse.

10. Case 6 — Slovak Telekom

Slovak Telekom v Commission

C-165/19 P, CJEU, 25 March 2021

This case concerned access to telecommunications infrastructure and conditions imposed on competitors.

It illustrates how control over an important infrastructure layer can affect downstream competition.

Affiliate relevance

An affiliate platform may similarly control:

tracking APIs;

conversion APIs;

affiliate IDs;

reporting systems;

payment interfaces.

If independent networks cannot obtain necessary technical access on reasonable terms, the resulting conduct may require analysis under Article 102.

The existence of alternative networks, technical necessity and actual competitive effects would be important.

11. Case 7 — Alphabet and Others

Alphabet and Others

C-233/23, CJEU, 25 February 2025

The case concerned interoperability between Google's digital platform and a third-party application.

The CJEU held that refusal to ensure interoperability can constitute an abuse in appropriate circumstances even where the platform is not strictly indispensable to the downstream market. The Court also stressed the importance of assessing whether the conduct is capable of hindering competition. (Infocuria)

Affiliate relevance

This is particularly useful for:

affiliate APIs;

tracking interfaces;

conversion systems;

data portability;

third-party attribution providers.

An affiliate platform could potentially restrict a rival's ability to integrate with its system.

The Alphabet judgment shows why interoperability can become a competition issue even in digital ecosystems where the platform is not literally the only possible route to market.

12. Case 8 — Servizio Elettrico Nazionale

Servizio Elettrico Nazionale and Others

C-377/20, CJEU, 12 May 2022

The CJEU considered exclusionary conduct by an undertaking with a historically protected position.

The case is useful for understanding how a dominant firm's advantages—such as access to information, customers or an established market position—can affect competitive conditions.

Affiliate relevance

An affiliate platform may possess historical data concerning:

affiliate conversion rates;

customer behaviour;

merchant performance;

product demand;

traffic sources.

The important question is whether the undertaking merely competes using those advantages or instead uses them through conduct capable of restricting competition.

13. Case 9 — Intel

Intel Corp. v Commission

C-413/14 P, CJEU, 6 September 2017

Intel concerned rebates and their possible exclusionary effects.

The CJEU required careful consideration of the circumstances relevant to assessing whether the conduct was capable of foreclosing competitors, including economic evidence where relevant.

Affiliate relevance

Suppose a dominant affiliate network tells advertisers:

"Use our network exclusively and receive a 20% lower commission."

This could raise questions concerning:

duration;

market coverage;

exclusivity;

ability of rivals to compete;

economic foreclosure;

efficiencies.

The Intel framework is therefore relevant when an affiliate platform uses financial incentives to induce customers not to use competing networks.

14. Case 10 — Google AdTech

The closest contemporary regulatory development is the European Commission's Google AdTech investigation.

In its 2025 decision, the Commission found that certain practices concerning Google's online display advertising intermediation services infringed Article 102 TFEU and Article 54 EEA. The decision concerned conduct on both the buy side and sell side of the advertising technology ecosystem. (European Commission)

Earlier, the Commission had alleged that Google favoured its AdX exchange through its publisher ad server and through Google Ads/DV360, creating concerns about self-preferencing and conflicts of interest. (European Commission)

Relevance to affiliate platforms

The structural analogy is strong:

Advertiser

↓

Affiliate/ad-buying intermediary

↓

Tracking/auction system

↓

Publisher/Affiliate

↓

Consumer

Where one undertaking controls several levels, competition authorities may examine whether its vertical position allows it to favour its own services or disadvantage rivals.

Importantly, this is an EU Commission enforcement decision, not a CJEU judgment, and its precise legal findings should not be automatically transferred to every affiliate-network case.

15. Exclusive Affiliate Agreements

A dominant platform may require an affiliate to:

use only its affiliate network.

Potential concerns increase where:

the affiliate has no realistic alternative;

the agreement covers a large portion of the market;

the agreement is long-term;

switching is expensive;

the platform controls an important traffic source;

competitors cannot achieve comparable scale.

The legal analysis may involve:

Article 102 TFEU;

Article 101 TFEU;

contractual law;

national competition law.

The Intel line of authority is particularly relevant to economically significant exclusivity and rebates.

16. Self-Preferencing

Imagine an affiliate network operates a marketplace containing thousands of affiliates.

It also owns:

its own cashback website;

its own coupon site;

its own comparison website.

If its algorithm consistently gives its own affiliate properties better placement, potential issues may resemble the self-preferencing concerns examined in Google Shopping.

Possible evidence includes:

ranking algorithms;

traffic allocation;

click-through rates;

conversion rates;

internal documents;

treatment of rival affiliates;

changes in rankings after integration.

But self-preferencing must still be connected to the applicable abuse-of-dominance analysis.

17. Affiliate Commission Discrimination

Suppose a dominant platform pays:

Own affiliate: 10%
Independent affiliate: 5%

The difference alone does not automatically constitute unlawful discrimination.

The legal questions include:

Are the transactions equivalent?

Is the undertaking dominant?

Are the different conditions objectively justified?

Do the differences place trading partners at a competitive disadvantage?

Do they affect competition?

Article 102(c) expressly identifies applying dissimilar conditions to equivalent transactions in a manner placing trading parties at a competitive disadvantage as a potential form of abuse. (Competition Policy)

18. Ranking Manipulation

Affiliate platforms often rank affiliates.

Possible ranking criteria include:

conversion rate;

commission;

merchant preference;

consumer engagement;

quality;

relevance.

A dominant platform could potentially manipulate rankings to favour its own affiliates.

This becomes particularly significant where affiliates depend heavily on platform traffic.

The Google Shopping case demonstrates the importance of analysing the interaction between a dominant platform's ranking mechanism and its own downstream service. (curia)

19. Data Advantages

Affiliate platforms can possess unique datasets.

For example:

100,000 affiliates
× millions of clicks
× millions of conversions
× thousands of merchants

could create a very large behavioural dataset.

That information may allow the platform to determine:

which products convert;

which affiliates are effective;

which consumers are valuable;

which merchants are growing;

which advertising channels are declining.

A dominant platform could potentially use these insights to compete with the very affiliates that generate the data.

This creates a potential platform-as-intermediary versus platform-as-competitor conflict.

20. Disintermediation Risk

One particularly important concern is disintermediation.

An affiliate platform might learn:

Affiliate A generates high-value customers for Merchant B.

The platform then potentially approaches Merchant B directly.

This is not automatically unlawful.

But if the platform imposes contractual or technical restrictions designed to prevent affiliates from moving to alternative networks while simultaneously using affiliate data to compete against them, the combined conduct may raise more serious competition questions.

21. API and Interoperability Restrictions

Affiliate platforms depend heavily on APIs.

Examples:

tracking API;

product-feed API;

conversion API;

payment API;

reporting API.

A dominant platform could potentially restrict:

access;

data frequency;

data granularity;

technical compatibility;

API documentation.

The Alphabet C-233/23 judgment is especially relevant to the legal treatment of digital interoperability. (Infocuria)

22. Tying

An affiliate platform might theoretically require:

Affiliate tracking + payment processing + advertising analytics

as one mandatory bundle.

Potential competition issues arise if:

the platform is dominant in one product;

the products are distinct;

customers are forced to take the second service;

rivals are foreclosed;

there is insufficient objective justification.

The exact analysis depends on the relevant markets and contractual structure.

23. Raising Rivals' Costs

A dominant affiliate platform could potentially increase competitors' costs by:

restricting data access;

increasing API charges;

imposing verification costs;

delaying tracking;

limiting product feeds;

changing technical standards;

requiring expensive integration.

The critical economic question becomes:

Does the conduct increase rivals' costs sufficiently to restrict effective competition?

Evidence would normally need to establish more than mere inconvenience.

24. Multi-Homing

Affiliate marketing often allows affiliates to join several networks simultaneously.

This is known as multi-homing.

For example:

Affiliate A:

Network X;

Network Y;

Network Z.

Multi-homing can reduce switching barriers.

But a dominant platform may attempt to restrict multi-homing through:

exclusivity;

technical incompatibility;

contractual restrictions;

differential commissions;

ranking penalties.

Therefore, the level of affiliate multi-homing can be an important economic factor in determining market power.

25. Network Effects

Affiliate platforms can exhibit strong network effects.

More advertisers

→ more campaigns

→ more affiliates.

More affiliates

→ more traffic

→ more advertisers.

More transactions

→ more data.

More data

→ better matching and fraud detection.

Better matching

→ more users.

This can create a self-reinforcing platform ecosystem.

However, network effects are evidence relevant to market power; they do not by themselves establish an abuse.

26. Data and GDPR

Affiliate tracking can involve:

cookies;

advertising identifiers;

IP-related information;

browsing behaviour;

purchase history;

device identifiers.

The Meta Platforms judgment demonstrates that competition authorities may need to consider data-protection compliance when assessing the conduct of a dominant digital platform. (curia)

Therefore, an affiliate dominance investigation may potentially involve three interacting areas:

Competition law + GDPR + platform regulation.

27. DMA Considerations

Where an affiliate ecosystem involves a designated gatekeeper service, the Digital Markets Act may become relevant in addition to traditional Article 102 enforcement.

Particularly important concepts include:

access to data;

interoperability;

transparency;

independent verification;

non-discrimination;

restrictions on combining data;

business-user rights.

The DMA is therefore capable of addressing some platform conduct through ex ante obligations rather than waiting for a traditional Article 102 investigation.

28. Civil and Commercial Claims

Dominance disputes can also produce private litigation.

Possible claims include:

Affiliate claim

unpaid commissions;

wrongful termination;

discriminatory treatment;

breach of contract.

Advertiser claim

excessive fees;

misleading attribution;

data restrictions;

exclusionary contractual conditions.

Competitor claim

exclusion;

refusal of access;

interoperability restrictions;

predatory conduct.

Consumer claim

Potentially:

misleading commercial practices;

unlawful tracking;

privacy violations.

The competition claim and the private contract claim remain legally distinct.

29. Evidence Required

A strong affiliate-platform case would typically examine:

Commercial evidence

affiliate agreements;

commission schedules;

exclusivity clauses;

termination provisions.

Technical evidence

APIs;

tracking systems;

ranking algorithms;

cookies;

conversion systems.

Economic evidence

market shares;

switching rates;

affiliate multi-homing;

commissions;

margins;

foreclosure rates.

Data evidence

affiliate performance;

advertiser concentration;

traffic;

conversion data;

customer acquisition data.

Internal evidence

emails;

strategy documents;

product-development documents;

pricing discussions;

internal presentations.

30. Main Legal Questions

A European authority or court could ask:

Question 1

What is the relevant market?

Affiliate networks? Advertising intermediation? Tracking? Attribution? A broader digital-advertising market?

Question 2

Is the platform dominant?

Market share is relevant but not decisive.

Question 3

What conduct occurred?

Exclusivity? Self-preferencing? Tying? Discrimination? Refusal of access?

Question 4

What is the competitive mechanism?

Foreclosure? Raising rivals' costs? Data leveraging?

Question 5

What are the effects or capability of effects?

Did or could the conduct restrict effective competition?

Question 6

Are there objective justifications?

Security, fraud prevention, privacy, quality control and technical constraints may matter.

31. Key Case Comparison

32. Practical Risk Matrix

These are risk categories, not conclusions that any particular conduct is unlawful.

33. Exam-Ready Conclusion

Affiliate marketing platform dominance risks arise when a platform becomes an important intermediary connecting advertisers, affiliates and consumers and then uses control over traffic, attribution, data, rankings, APIs, commissions or contractual access in a way capable of restricting competition.

The principal European authorities include:

Google Shopping (C-48/22 P) — self-preferencing;

Google AdSense (T-334/19) — advertising intermediation and contractual restrictions;

Meta Platforms (C-252/21) — data processing and competition;

Bronner (C-7/97) — access and indispensability;

Deutsche Telekom (C-152/19 P) — exclusionary access/pricing;

Slovak Telekom (C-165/19 P) — infrastructure access;

Alphabet (C-233/23) — digital interoperability;

Intel (C-413/14 P) — exclusionary rebates and economic effects.

The Commission's current Article 102 framework expressly considers dominance, barriers to entry, buyer power and vertical integration, while Article 102 itself identifies practices such as discriminatory conditions and tying among potential forms of abuse. (Competition Policy)

Ultra-basic rule

An affiliate platform's large size or vertical integration is not by itself unlawful. The central European competition-law question is whether a dominant platform uses control over affiliates, advertisers, attribution, data, rankings or interoperability to exclude rivals or otherwise abuse its market position.

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