Competition Law and Network Centrality and Antitrust Analysis

1. Introduction

Network centrality is increasingly important in competition law because market power in digital and interconnected markets may depend not merely on a firm's market share, but on how central the firm is within a network of users, suppliers, platforms, data flows, payment systems, infrastructure, or complementary services.

A firm can become a critical intermediary connecting otherwise separate groups. The more indispensable its position is to the functioning of the network, the greater the possibility that it can exercise bottleneck power, gatekeeper power, exclusionary power, or ecosystem leverage.

Traditional competition analysis generally asks:

• What is the relevant market?
• What is the firm's market share?
• Does the firm possess substantial market power?
• Has it engaged in exclusionary or exploitative conduct?

Network-centrality analysis adds questions such as:

• How many important participants depend upon the firm?
• Can users realistically bypass the intermediary?
• Does the firm control an essential connection between different sides of the market?
• Does the firm's position create network effects?
• Can control over one network be leveraged into adjacent markets?
• Would removing or bypassing the firm materially fragment the network?

Thus, centrality is generally an analytical indicator of competitive significance rather than an independent legal test of dominance.

2. Meaning of Network Centrality

In network economics, a market can be represented as a network:

Nodes → participants in the market
Edges → economic relationships between participants

For example, in a digital platform:

Consumers ↔ Platform ↔ Sellers ↔ Advertisers ↔ Developers

The platform may occupy a highly central position because many economically significant relationships pass through it.

Major forms of centrality

A. Degree Centrality

Measures the number of direct connections possessed by a firm.

A platform with millions of directly connected users and merchants has high degree centrality.

Competition significance:
High degree centrality may indicate that a platform has a large number of direct commercial relationships.

B. Betweenness Centrality

Measures how frequently a node lies on the shortest paths connecting other nodes.

Conceptually:

BC(v)=∑s≠v≠tσst(v)σstBC(v)=\sum_{s\neq v\neq t}\frac{\sigma_{st}(v)}{\sigma_{st}}

where:

• vv = the firm being examined;
• σst\sigma_{st} = number of shortest paths between nodes ss and tt;
• σst(v)\sigma_{st}(v) = number of those paths passing through vv.

A firm with high betweenness centrality can function as a bottleneck.

Examples include:

• payment networks;
• app stores;
• online marketplaces;
• search engines;
• communications infrastructure;
• cloud infrastructure;
• railway or electricity networks.

C. Eigenvector Centrality

A firm may be important not simply because it has many connections, but because it is connected to other important nodes.

A connection to a major bank, dominant retailer, major developer, or strategically important supplier may be more significant than numerous insignificant connections.

D. Closeness Centrality

Measures how close a node is to other nodes within the network.

A firm with high closeness centrality can potentially reach many participants efficiently.

3. Why Centrality Matters in Competition Law

Traditional market-share analysis can be inadequate in network industries.

Consider two firms:

Firm A has the higher market share, but Firm B may possess greater strategic importance because competitors and customers depend upon its infrastructure.

Therefore:

Market share measures size; network centrality can illuminate structural position.

However, centrality should not automatically be equated with dominance.

A highly central firm may still face:

• multi-homing;
• low switching costs;
• competitive alternatives;
• interoperability;
• potential entry;
• countervailing buyer power.

4. Network Effects and Centrality

Network effects occur when the value of a product or service changes as the number of users changes.

Direct network effects

The value of a service increases as more users join.

Example:

Messaging platform

More users → more people available to communicate with → greater value.

Indirect network effects

More users on one side attract participants on another side.

Example:

Marketplace

More consumers → more sellers → more product variety → more consumers.

This can create a feedback loop:

Users↑→Sellers↑→Variety↑→Users↑Users \uparrow \rightarrow Sellers \uparrow \rightarrow Variety \uparrow \rightarrow Users \uparrow

A central platform can therefore become increasingly difficult to displace.

5. Network Centrality and Market Power

Centrality can contribute to market power through several mechanisms.

5.1 Bottleneck control

A central intermediary may control access between otherwise disconnected participants.

5.2 Switching costs

Users may hesitate to leave because abandoning the central platform means losing:

• contacts;
• data;
• reputation;
• transaction history;
• applications;
• customers;
• interoperability.

5.3 Network effects

A large network can reinforce the position of an incumbent.

5.4 Data advantages

A central platform may receive data from multiple sides of the network.

This can create:

Data accumulation → improved service → more users → more data

5.5 Ecosystem leverage

Centrality in one market may permit expansion into another.

For example:

Operating system → app store → payments → advertising → cloud services

The competition concern is not merely size, but the ability to use one central position to influence adjacent markets.

6. Network Centrality in Relevant-Market Definition

Network analysis can supplement conventional market definition.

Competition authorities may examine:

• user flows;
• transaction flows;
• data flows;
• payment flows;
• switching patterns;
• interoperability;
• platform dependencies;
• geographic network structures.

Example

Suppose a payment platform connects:

10,000 merchants ↔ 20 banks ↔ 5 million consumers.

A simple market-share calculation might not fully capture the platform's competitive significance.

A centrality analysis may reveal that the platform is the principal intermediary through which competitors must reach customers.

7. Network Centrality and Dominance

Centrality can be relevant to determining whether market power exists under dominance provisions.

Important indicators include:

Structural indicators

• market share;
• number of connected users;
• transaction volume;
• network coverage;
• number of business relationships.

Dependency indicators

• percentage of transactions routed through the platform;
• number of commercially viable alternatives;
• switching costs;
• interoperability barriers.

Dynamic indicators

• rate of user growth;
• ability of competitors to attract users;
• network expansion;
• data accumulation;
• technological lock-in.

8. Network Centrality and Exclusionary Conduct

A central firm may engage in conduct designed to prevent competitors from reaching the network.

Potential theories include:

A. Refusal to deal

A dominant intermediary may deny access to a network or infrastructure.

B. Interoperability restrictions

A platform may deliberately make its system incompatible with rival systems.

C. Self-preferencing

A central platform may give preferential treatment to its own downstream services.

D. Exclusive dealing

A platform may require participants to deal exclusively with it.

E. Tying and bundling

The central service may be tied to an adjacent product.

F. Data foreclosure

A central platform may prevent competitors from obtaining commercially important data.

G. Predatory or strategic pricing

A platform may sacrifice short-term profits to expand network centrality and subsequently exploit increased market power.

9. Network Centrality and Essential-Facility Analysis

Network centrality has a particularly close relationship with the essential-facilities doctrine.

A facility becomes competitively significant where competitors cannot realistically operate without access to it.

However:

Centrality ≠ automatic essential facility.

Competition law generally requires additional legal conditions.

Relevant considerations may include:

1. indispensability;
2. absence of realistic alternatives;
3. technical feasibility of access;
4. ability to duplicate the facility;
5. economic viability of duplication;
6. effect of refusal on competition;
7. justification for the refusal.

10. Network Centrality and Digital Platforms

Digital platforms are particularly susceptible to centrality effects.

Search engines

Users → Search engine → Websites/advertisers

App stores

Developers → App store → Consumers

Marketplaces

Sellers → Marketplace → Consumers

Payment platforms

Merchants → Payment network → Banks/consumers

Social networks

Users → Social network → Advertisers/content providers

The platform can become the central node connecting multiple groups.

11. Important Case Laws

Case 1: United States v. Microsoft Corp. (2001)

Court: U.S. Court of Appeals for the District of Columbia Circuit

Microsoft involved the competitive significance of the Windows operating-system platform.

Relevance to network centrality

Windows occupied a central position in the PC software ecosystem.

The operating system connected:

• computer manufacturers;
• consumers;
• application developers;
• browsers;
• software products.

The court considered Microsoft's conduct toward browser competition, including contractual restrictions and other practices that protected the Windows platform.

Competition-law significance

The case illustrates how control over a central platform can enable a firm to restrict competitive threats in adjacent markets.

It is particularly relevant to:

• platform power;
• entry barriers;
• network effects;
• interoperability;
• exclusionary conduct;
• leveraging.

12. Case 2: United States v. Terminal Railroad Association of St. Louis (1912)

Court: U.S. Supreme Court

The Terminal Railroad Association controlled essential railroad terminal facilities in St. Louis.

Network-centrality dimension

The terminal system occupied a strategically central position in the regional railroad network.

Competing railroads needed access to the terminal infrastructure to reach important destinations.

Consequently, control over the central infrastructure could affect competition among downstream railroad operators.

Principle

The case is a foundational example of how control over a strategically central network facility can create competitive concerns when competitors cannot realistically bypass it.

Relevance

It provides an early foundation for analysing:

• bottleneck infrastructure;
• access discrimination;
• network foreclosure;
• essential facilities;
• refusal to deal.

13. Case 3: Aspen Skiing Co. v. Aspen Highlands Skiing Corp. (1985)

Court: U.S. Supreme Court

The dispute concerned four major ski areas in Aspen, where competitors had previously participated in a common multi-area ticket system.

Aspen Skiing subsequently discontinued cooperation with the smaller rival.

Network-centrality dimension

The common ticket arrangement connected multiple ski areas into a broader consumer network.

The ability to participate in the network increased the attractiveness of the ski product.

Competition significance

The case is relevant to the principle that a dominant firm may face antitrust scrutiny when it terminates a commercially meaningful cooperative relationship under circumstances indicating exclusionary conduct.

Network lesson

A firm can obtain competitive advantages by controlling participation in an interconnected network.

14. Case 4: Ohio v. American Express Co. (2018)

Court: U.S. Supreme Court

American Express operates a two-sided payment network connecting:

• cardholders; and
• merchants.

Network-centrality dimension

The payment network functions as an intermediary connecting two groups whose participation affects the value of the network to the other side.

This makes the case highly relevant to network economics.

Key principle

For certain two-sided transaction platforms, competition analysis must consider the interdependent relationship between both sides of the platform rather than treating them as completely separate markets.

Importance

The case demonstrates that:

Network structure can influence how antitrust markets and competitive effects are analysed.

15. Case 5: United States v. Visa U.S.A., Inc. and MasterCard International Inc. (2001)

The U.S. Department of Justice challenged restrictions imposed by Visa and MasterCard on member banks' participation in competing payment networks.

Network-centrality dimension

Payment-card networks possess significant network characteristics:

Cardholders ↔ Banks ↔ Merchants ↔ Payment networks

The more participants a network contains, the more valuable participation can become.

Competition issue

The challenged rules could make it more difficult for competing networks to obtain issuing-bank relationships.

Network significance

The case demonstrates how contractual restrictions can protect the position of a central network by limiting participants' ability to connect with competing networks.

16. Case 6: European Commission v. Google Android (2018)

Authority: European Commission

The Commission examined Google's contractual arrangements concerning Android devices, including:

• Google Search;
• Google Play Store;
• Chrome;
• Android operating systems.

Network-centrality dimension

Android formed a central layer connecting:

Device manufacturers → developers → consumers → applications → search services

The Commission considered whether contractual practices strengthened Google's position in search and related markets.

Competition significance

The case illustrates ecosystem centrality and leveraging.

A platform may use its central position in one layer of a digital ecosystem to reinforce its position in another.

17. Case 7: Google Search (Shopping) — European Commission (2017)

The European Commission found that Google had abused its dominant position by giving more favourable positioning to its own comparison-shopping service in general search results.

Network-centrality dimension

Search engines can function as central gateways between:

Consumers ↔ Websites ↔ Online merchants

Control over visibility at the gateway can materially affect traffic reaching competing services.

Competition significance

The case demonstrates the importance of gateway position.

Even when competing websites remain technically accessible, a central intermediary may influence whether consumers actually reach them.

Network lesson

Access to the network is not enough; control over routing within the network may itself have competitive significance.

18. Case 8: Bronner v. Mediaprint (1998)

Court: Court of Justice of the European Union

The case concerned access to a newspaper-delivery system.

Network-centrality dimension

The established delivery network provided an infrastructure through which newspapers could reach customers.

The applicant sought access to that system.

Competition significance

The CJEU applied a demanding test for compulsory access to infrastructure under Article 102 TFEU.

The case is important because it demonstrates that:

A highly central infrastructure does not automatically generate a duty to provide access.

Indispensability and the absence of realistic alternatives remain critical.

19. Case 9: IMS Health v NDC Health (2004)

Court: Court of Justice of the European Union

The case concerned access to a data structure used in the pharmaceutical information industry.

Network-centrality dimension

The relevant information architecture had become highly significant to pharmaceutical-market information services.

Access to the established structure could therefore affect competitors' ability to operate.

Importance

The case developed the European approach to refusal-to-license/refusal-to-deal situations involving intellectual property and market access.

It is particularly useful for analysing:

• data infrastructure;
• interoperability;
• network standards;
• market entry;
• indispensability.

20. Case 10: Slovak Telekom v Commission (2021)

Court: Court of Justice of the European Union

The case concerned access to telecommunications infrastructure controlled by a dominant operator.

Network-centrality dimension

Telecommunications infrastructure is inherently network-based.

The incumbent's control over infrastructure could influence competitors' ability to reach customers.

Competition significance

The case illustrates the interaction between:

• dominance;
• access obligations;
• infrastructure control;
• foreclosure;
• regulatory and competition-law frameworks.

It is especially relevant to network bottleneck analysis.

21. Case-Law Synthesis

22. Network Centrality and Multi-Sided Markets

A particularly important application is the multi-sided platform.

Suppose:

Consumers↔Platform↔SellersConsumers \leftrightarrow Platform \leftrightarrow Sellers

The platform may simultaneously possess:

• high user centrality;
• high seller centrality;
• transaction centrality;
• data centrality.

Its competitive significance can therefore exceed what a single-sided market-share measurement suggests.

Example

If 80% of consumers use a platform but sellers can easily reach consumers through four competing platforms, centrality may be less durable.

Conversely, if consumers use multiple platforms but sellers depend upon one platform because it controls access to a critical customer group, the network structure may generate substantial bargaining power.

23. Multi-Homing and Centrality

Multi-homing occurs when users participate in multiple networks simultaneously.

For example:

A consumer may use:

• Platform A;
• Platform B;
• Platform C.

Multi-homing can reduce the power of a central platform.

Antitrust questions

Authorities may examine:

1. How many users multi-home?
2. How costly is multi-homing?
3. Do suppliers multi-home?
4. Are users locked into one network?
5. Are data and reputation portable?
6. Can competitors interoperate?

Thus:

High Centrality+Low Switching CostsHigh\ Centrality + Low\ Switching\ Costs

does not necessarily equal durable dominance.

Whereas:

High Centrality+Strong Network Effects+High Switching CostsHigh\ Centrality + Strong\ Network\ Effects + High\ Switching\ Costs

can create significantly stronger barriers to entry.

24. Centrality and Data Power

Data can itself form a network.

For example:

More Users→More Data→Better Algorithms→Better Product→More UsersMore\ Users \rightarrow More\ Data \rightarrow Better\ Algorithms \rightarrow Better\ Product \rightarrow More\ Users

A central platform may therefore benefit from a data-network effect.

Competition authorities may investigate:

• exclusive data access;
• refusal to provide data portability;
• discriminatory API access;
• preferential access to platform-generated data;
• combining datasets across services;
• restrictions on data interoperability.

25. Centrality and Algorithmic Competition

Algorithmic systems can strengthen network centrality.

A platform may use algorithms to determine:

• search rankings;
• recommendations;
• seller visibility;
• advertising placement;
• prices;
• customer matching.

The centrality concern arises when the intermediary controls the algorithm through which market participants obtain access to one another.

Therefore:

Algorithmic control can become a form of network-routing power.

26. Centrality and Self-Preferencing

Self-preferencing becomes particularly significant where the platform controls a central gateway.

The structure is:

Platform → controls gateway → operates competing downstream service

The platform may potentially:

• rank its own service more prominently;
• reduce competitors' visibility;
• provide superior access to data;
• impose discriminatory terms;
• give its own products preferential technical integration.

The competition analysis should distinguish between:

• legitimate product improvement;
• neutral ranking;
• objectively justified integration; and
• conduct that materially disadvantages competitors using the central gateway.

27. Centrality and Mergers

Network centrality is increasingly relevant to merger control.

A transaction may increase centrality by combining:

• two major user networks;
• two payment systems;
• a platform and a critical data provider;
• a marketplace and logistics infrastructure;
• a cloud platform and software ecosystem.

Important merger questions

1. Will the merger increase network concentration?
2. Will it eliminate an important alternative network?
3. Will interoperability decrease?
4. Will switching costs increase?
5. Will data advantages increase?
6. Will competitors lose access to important users?
7. Will the merged firm become a critical gateway?

28. Centrality and Nascent Competition

A smaller company may have a small current market share but occupy an important strategic position.

For example:

Emerging platform → innovative technology → rapidly growing user network

An acquisition of such a company could remove a potential competitive constraint.

Thus, network analysis may examine:

• growth trajectory;
• user engagement;
• interoperability;
• technology;
• switching;
• network expansion;
• strategic importance.

This complements conventional market-share analysis.

29. Centrality and Interoperability Remedies

Where centrality creates competitive problems, authorities may consider remedies such as:

Structural remedies

• divestiture;
• separation of business units;
• removal of vertical integration.

Behavioural remedies

• non-discriminatory access;
• interoperability;
• API access;
• data portability;
• ranking transparency;
• prohibition of exclusive arrangements.

Network-oriented remedies

The objective is often to prevent the dominant intermediary from becoming an unavoidable bottleneck.

30. Analytical Framework for Competition Authorities

A useful network-centrality framework can be structured as follows:

Step 1 — Identify the network

Determine:

• nodes;
• connections;
• intermediary relationships;
• network boundaries.

Step 2 — Identify the central firm

Measure:

• degree centrality;
• betweenness;
• eigenvector centrality;
• transaction centrality.

Step 3 — Examine network effects

Determine whether additional users increase network value.

Step 4 — Examine dependency

Ask:

• Can participants bypass the firm?
• Are alternatives commercially viable?
• Is switching costly?

Step 5 — Examine conduct

Investigate:

• exclusion;
• tying;
• bundling;
• self-preferencing;
• discriminatory access;
• exclusive dealing;
• refusal to deal.

Step 6 — Examine competitive effects

Determine whether the conduct:

• forecloses rivals;
• raises entry barriers;
• reduces innovation;
• increases switching costs;
• increases prices;
• reduces quality;
• reduces consumer choice.

Step 7 — Examine efficiencies and justification

A central platform may have legitimate reasons for:

• security restrictions;
• technical integration;
• fraud prevention;
• quality control;
• privacy protection.

Step 8 — Select appropriate remedy

Potential remedies include:

• access;
• interoperability;
• data portability;
• non-discrimination;
• structural separation.

31. Network Centrality vs Traditional Market Share

The two approaches should generally be complementary rather than mutually exclusive.

32. Limitations of Network-Centrality Analysis

Centrality should not be treated as a substitute for legal analysis.

A. Centrality does not equal dominance

A highly connected firm may face vigorous competition.

B. Network structure can change rapidly

Digital markets may experience rapid technological disruption.

C. Measurement difficulties

Different definitions of nodes and edges can produce different centrality results.

D. False positives

A central platform may be central because it provides an efficient service rather than because it engages in exclusionary conduct.

E. Regulation may explain centrality

A firm's central position may result from legitimate technical standards or regulatory architecture.

F. Network effects may be reversible

New technologies, interoperability, or multi-homing can weaken incumbent network advantages.

33. Competition-Law Test

A concise analytical test can be formulated as:

Centrality → Dependency → Market Power → Conduct → Foreclosure → Competitive Harm → Justification → Remedy

Centrality

Is the firm an important intermediary?

↓

Dependency

Do customers or competitors depend upon it?

↓

Market power

Can the firm materially influence competitive conditions?

↓

Conduct

Has it restricted access, interoperability, ranking, data, or participation?

↓

Foreclosure

Are competitors prevented or disadvantaged from reaching customers?

↓

Harm

Does the conduct reduce competition, innovation, quality, or consumer choice?

↓

Justification

Is there a legitimate and proportionate explanation?

↓

Remedy

What intervention, if any, is appropriate?

34. Indian Competition-Law Relevance

Under the Competition Act, 2002, network centrality can be relevant particularly to the assessment of:

• relevant market;
• dominance;
• entry barriers;
• consumer dependence;
• access to infrastructure;
• refusal to deal;
• discriminatory conditions;
• tying and bundling;
• leveraging;
• combinations involving digital ecosystems.

Section 4 analysis of dominance is particularly compatible with examining factors such as:

• economic strength;
• size and importance;
• entry barriers;
• consumer dependence;
• market structure;
• vertical integration.

Network centrality can therefore serve as an economic evidentiary tool supporting the broader statutory analysis, rather than replacing the statutory tests.

35. Key Takeaways

1. Network centrality measures a firm's structural importance within an economic network.
2. Central firms may function as gatekeepers or bottlenecks.
3. Betweenness centrality is particularly relevant to access and intermediary power.
4. Network effects can reinforce centrality through positive feedback loops.
5. Centrality can strengthen entry barriers and switching costs.
6. Multi-sided platforms require analysis of interconnected user groups.
7. Self-preferencing can be especially significant when a firm controls a central gateway.
8. Refusal to deal and essential-facility cases provide important historical foundations.
9. Digital ecosystems make data, APIs, interoperability, and ranking systems central competition issues.
10. Centrality does not by itself establish dominance or unlawful conduct.
11. Competition authorities must connect network position to market power, conduct, foreclosure, and competitive effects.
12. The most useful framework is:

Centrality → Dependency → Power → Conduct → Foreclosure → Harm\boxed{\text{Centrality → Dependency → Power → Conduct → Foreclosure → Harm}}

Conclusion

Network centrality provides competition law with a structural lens for analysing markets in which economic relationships depend upon interconnected platforms, infrastructure, data, or intermediaries. Traditional market shares remain important, but they may not fully capture the competitive significance of a firm that controls a critical connection between large groups of market participants.