1. Introduction

Digital Infrastructure Fragility Indices are quantitative or qualitative frameworks used to measure how vulnerable digital infrastructure is to disruption, concentration, failure, cyberattack, technological dependency, regulatory intervention, or cascading system failure.

They may assess the fragility of:

• cloud-computing infrastructure;
• data centres;
• telecommunications networks;
• internet exchange points;
• submarine cables;
• DNS and routing infrastructure;
• digital identity systems;
• payment infrastructure;
• AI-compute infrastructure;
• app stores and operating systems;
• semiconductor and hardware supply chains;
• critical government digital infrastructure; and
• platforms that function as essential gateways for businesses or consumers.

From a competition-law perspective, the concept is particularly important because infrastructure that appears technically robust may nevertheless be economically fragile if access depends upon one dominant undertaking, one cloud provider, one operating system, one identity provider, one API, or one data infrastructure.

A useful conceptual formula is:

Digital Infrastructure Fragility = Concentration + Dependency + Substitutability Constraints + Failure Propagation + Recovery Difficulty

Fragility therefore differs from ordinary market power. A firm can possess significant market power because alternatives are weak, while infrastructure can be fragile because the failure or exclusion of one component causes systemic consequences throughout interconnected markets.

2. Meaning of Digital Infrastructure Fragility

Digital infrastructure is fragile where disruption to a relatively small number of technological or economic components can produce disproportionately large consequences.

For example, a digital market may contain:

Cloud provider → API → payment system → identity verification → consumer platform

If one provider controls a critical component, its outage or exclusionary conduct may affect several downstream markets.

Fragility therefore has at least five dimensions:

A. Technical fragility

This concerns:

• single points of failure;
• inadequate redundancy;
• outdated hardware;
• insecure software;
• weak authentication;
• insufficient backup systems;
• routing vulnerabilities; and
• dependency on proprietary technologies.

B. Economic fragility

This concerns:

• excessive supplier concentration;
• high switching costs;
• network effects;
• dependency on dominant platforms;
• lack of interoperable alternatives; and
• foreclosure of competing infrastructure providers.

C. Institutional fragility

Government or regulatory systems may become dependent upon a small number of private infrastructure providers.

D. Supply-chain fragility

A digital system can depend upon:

• semiconductor manufacturers;
• GPU suppliers;
• cloud infrastructure;
• telecommunications equipment;
• undersea cables;
• specialised software;
• cybersecurity vendors; and
• energy infrastructure.

E. Systemic fragility

The most important dimension is cascading failure.

A failure in one infrastructure layer may propagate through several markets.

3. What Is a Digital Infrastructure Fragility Index?

A Digital Infrastructure Fragility Index (DIFI) can be designed as a composite indicator.

For example:

DIFI=w1C+w2D+w3S+w4R+w5I+w6FDIFI = w_1C + w_2D + w_3S + w_4R + w_5I + w_6F

Where:

• C = infrastructure concentration;
• D = dependency;
• S = lack of substitutability;
• R = recovery difficulty;
• I = interoperability weakness; and
• F = failure-propagation risk.

The weights can be adjusted depending upon the sector.

A cloud-computing index might assign greater weight to concentration and switching costs, whereas a telecommunications index might place greater weight on redundancy and physical infrastructure.

4. Major Components of the Index

4.1 Infrastructure concentration

The first variable is the number and relative importance of infrastructure providers.

A standard concentration measure can include the Herfindahl-Hirschman Index (HHI):

HHI=∑si2HHI = \sum s_i^2

where sis_i represents each provider's market share.

However, ordinary market-share concentration is insufficient.

A digital infrastructure index should also consider criticality-weighted concentration.

For example:

The ordinary HHI might not appear catastrophic, but infrastructure fragility could be high because Provider A controls most critical infrastructure.

5. Dependency Ratio

A second variable is the degree to which downstream businesses depend upon a particular infrastructure provider.

For example:

DependencyRatio=critical functions dependent on providertotal critical functionsDependency Ratio = \frac{\text{critical functions dependent on provider}} {\text{total critical functions}}

A company might technically have three cloud suppliers but still be highly dependent upon one because its:

• databases;
• authentication;
• APIs;
• machine-learning models; and
• payment systems

all operate on the same provider.

Therefore, nominal multi-homing does not necessarily mean genuine resilience.

6. Substitutability

An infrastructure provider may be difficult to replace because switching requires:

• data migration;
• software rewriting;
• employee retraining;
• regulatory certification;
• interoperability modifications;
• contractual renegotiation;
• hardware replacement; or
• rebuilding technical architecture.

The relevant question is therefore:

Can a customer realistically switch providers within the time required to prevent serious economic harm?

This is especially important in competition law.

7. Recovery Time

A fragility index should measure the time required to restore essential services.

Possible categories are:

• minutes;
• hours;
• days;
• weeks; or
• months.

A system requiring six months to migrate from a failed infrastructure provider is substantially more fragile than one capable of switching within several hours.

8. Failure Propagation

The index should measure whether failure of one component can spread to other markets.

For example:

Cloud outage

↓

Payment-processing interruption

↓

Retail-platform interruption

↓

Logistics disruption

↓

Consumer supply disruption

This creates systemic digital fragility.

9. Interoperability

Interoperability reduces fragility because it enables users to move between systems.

Competition authorities may therefore examine:

• open APIs;
• technical standards;
• data portability;
• interoperability obligations;
• identity portability;
• cloud portability;
• messaging interoperability; and
• compatibility requirements.

Where interoperability is weak, infrastructure concentration becomes more dangerous.

10. Data Portability

Data portability is closely related to infrastructure resilience.

If users cannot easily transfer:

• datasets;
• metadata;
• customer histories;
• authentication information;
• configurations; or
• machine-learning models,

then switching costs increase.

Consequently:

Data portability can operate as a competition and resilience mechanism simultaneously.

11. Digital Infrastructure Fragility and Competition Law

Fragility indices can be relevant to several competition-law questions.

Article 102 / Section 19a-type analysis

Authorities may ask whether a dominant undertaking controls infrastructure that competitors cannot realistically bypass.

Essential-facility considerations

The issue becomes particularly significant where access to infrastructure is indispensable for competing downstream.

Refusal to deal

A dominant infrastructure provider may potentially abuse its position by refusing access to essential infrastructure.

Self-preferencing

A vertically integrated infrastructure provider could potentially favour its downstream services.

Margin squeeze

A vertically integrated provider might charge competitors infrastructure prices that make effective downstream competition impossible.

Exclusive dealing

Long-term exclusivity can increase infrastructure fragility by preventing alternative providers from developing.

12. Six Important Case Laws

12.1 United Brands v Commission — 1978

Case: United Brands Company and United Brands Continentaal BV v Commission, Case 27/76.

The European Court of Justice examined dominance and the ability of a dominant undertaking to behave independently of competitors, customers and consumers.

Relevance to digital infrastructure fragility

The case provides an important conceptual foundation for analysing infrastructure providers.

A digital infrastructure undertaking may become particularly significant where customers cannot effectively discipline it because:

• alternatives are unavailable;
• switching is expensive;
• infrastructure is highly concentrated; and
• customers are locked into the provider.

The case therefore helps establish the relationship between economic dependence and market power.

12.2 Commercial Solvents v Commission — 1974

Cases: Joined Cases 6/73 and 7/73, Istituto Chemioterapico Italiano SpA and Commercial Solvents Corporation v Commission.

The Court considered the refusal by a dominant undertaking to supply an important input to a downstream competitor.

Digital infrastructure relevance

The principle is particularly relevant to:

• cloud infrastructure;
• operating systems;
• identity services;
• payment infrastructure;
• APIs;
• telecommunications infrastructure; and
• other upstream digital inputs.

Where an infrastructure provider controls an indispensable input and uses that control to eliminate downstream competition, infrastructure dependency can become an abuse-of-dominance concern.

Fragility principle

The case supports the proposition that control over an upstream bottleneck can have downstream competitive consequences.

12.3 Bronner v Mediaprint — 1998

Case: Oscar Bronner GmbH & Co. KG v Mediaprint Zeitungs und Zeitschriftenverlag GmbH & Co. KG, Case C-7/97.

This is one of the most important EU cases concerning essential facilities.

The Court established a demanding test for compulsory access to infrastructure controlled by a dominant undertaking.

The infrastructure generally must be indispensable, and duplication must not be realistically possible.

Digital infrastructure relevance

The principles are directly relevant to:

• cloud infrastructure;
• digital identity networks;
• payment systems;
• internet infrastructure;
• app ecosystems;
• telecommunications networks; and
• data-access infrastructures.

A fragility index can help establish whether alternative infrastructure genuinely exists.

For example:

If an alternative provider exists theoretically but switching would take years and require complete technological reconstruction, the practical substitutability question becomes much more important.

12.4 IMS Health v NDC Health — 2004

Case: IMS Health GmbH & Co. OHG v NDC Health GmbH & Co. KG, Case C-418/01.

The Court considered access to an infrastructure protected by intellectual property rights and the exceptional circumstances under which compulsory licensing could be required.

Digital infrastructure relevance

The case is important for modern digital infrastructure involving:

• proprietary data structures;
• technical standards;
• APIs;
• interoperability specifications;
• software interfaces; and
• proprietary digital architectures.

A dominant undertaking may create infrastructure that competitors cannot realistically reproduce.

The competition-law question then becomes whether proprietary control has transformed into structural exclusion.

12.5 Slovak Telekom v Commission — 2021

Case: Slovak Telekom a.s. v European Commission, Joined Cases C-152/19 P and C-165/19 P.

The case concerned exclusionary conduct in telecommunications infrastructure and the application of the essential-facilities framework.

Digital infrastructure relevance

This is particularly important because telecommunications networks are foundational digital infrastructure.

The case illustrates how competition law can address:

• access restrictions;
• infrastructure bottlenecks;
• foreclosure;
• downstream competitors; and
• discriminatory access conditions.

Fragility-index significance

A fragility index can supplement traditional market analysis by identifying whether access to a network is structurally indispensable.

12.6 Google Shopping — 2024

Case: Google and Alphabet v Commission (Google Shopping), Case C-48/22 P.

The Court of Justice upheld the core finding concerning Google's abuse involving the positioning and treatment of its comparison-shopping service.

Digital infrastructure relevance

The significance extends beyond search results.

Digital ecosystems increasingly combine:

• search;
• advertising;
• operating systems;
• cloud infrastructure;
• data;
• identity;
• payment systems; and
• AI services.

A dominant undertaking controlling a major digital gateway can therefore influence access to downstream markets.

Fragility implication

Where a single digital gateway becomes unavoidable for commercial access, the relevant infrastructure may become economically fragile even without physical failure.

This introduces the concept of:

Competitive fragility — the vulnerability of downstream markets to unilateral conduct by a dominant infrastructure gatekeeper.

13. Additional Important Case Laws

13.7 Microsoft v Commission — 2007

Case: Microsoft Corp. v Commission, Case T-201/04.

The General Court addressed interoperability information, tying and Microsoft's position in software markets.

Importance

The case is highly relevant to:

• interoperability;
• technical information;
• platform ecosystems;
• operating-system dependency; and
• technological foreclosure.

Digital infrastructure fragility increases when interoperability is controlled by one ecosystem.

13.8 Google Android — 2022

Case: Google and Alphabet v Commission, Case T-604/18.

The General Court examined Google's contractual restrictions involving Android and mobile-device ecosystems.

Importance

The case demonstrates how control over one technological layer can reinforce dominance across adjacent layers.

This is relevant to fragility indices because:

Ecosystem concentration can be more important than concentration in any individual market.

13.9 Deutsche Telekom v Commission — 2010

Case: Deutsche Telekom AG v Commission, Case C-280/08 P.

The Court considered margin squeeze in telecommunications.

Digital infrastructure relevance

Infrastructure owners that also compete downstream can potentially use pricing structures to disadvantage rivals.

A fragility index should therefore measure not merely physical concentration but also vertical integration.

13.10 ENEL v Commission — 2024

The modern European competition framework increasingly recognises the importance of digital ecosystems, infrastructure dependencies and strategic inputs.

The broader lesson from infrastructure-related competition jurisprudence is that control over indispensable economic inputs can generate competitive risks even when the infrastructure itself is not the final consumer product.

14. Proposed Digital Infrastructure Fragility Index

A practical index could contain the following components:

A resulting score could be classified as:

These numerical thresholds are analytical proposals, not legally established statutory categories.

15. Competition-Law Interpretation of High Fragility

A high score should not automatically establish an antitrust violation.

Instead, it should trigger closer examination of:

1. market definition;
2. dominance;
3. entry barriers;
4. network effects;
5. switching costs;
6. interoperability;
7. exclusionary conduct;
8. access restrictions;
9. discrimination;
10. vertical integration;
11. self-preferencing;
12. foreclosure; and
13. consumer and systemic effects.

This distinction is essential.

Fragility is an economic-risk indicator; illegality requires application of the relevant legal test.

16. Digital Infrastructure Fragility and Section 19a GWB

Under Section 19a of the German Competition Act (GWB), particularly significant cross-market importance can justify enhanced scrutiny of certain large digital undertakings.

Digital infrastructure fragility can be highly relevant because a platform may control several interconnected layers:

Operating system

↓

App distribution

↓

Identity

↓

Payments

↓

Advertising

↓

Cloud

↓

AI services

The more layers controlled by one undertaking, the greater the possibility that an apparently isolated infrastructure advantage can become an ecosystem-wide competitive bottleneck.

17. Fragility and AI Infrastructure

AI introduces a new category of digital infrastructure fragility.

Modern AI markets may depend upon:

• advanced GPUs;
• semiconductor fabrication;
• high-bandwidth memory;
• cloud data centres;
• electricity;
• specialised networking;
• foundation models;
• inference APIs;
• training datasets; and
• model-serving infrastructure.

If only a small number of undertakings control these inputs, downstream AI companies may become structurally dependent.

This creates an AI infrastructure fragility index incorporating:

AI Fragility=Compute Concentration+Chip Concentration+Cloud Dependency+Model Dependency+Data DependencyAI\ Fragility = Compute\ Concentration + Chip\ Concentration + Cloud\ Dependency + Model\ Dependency + Data\ Dependency

This can become particularly important where infrastructure suppliers are vertically integrated into downstream AI applications.

18. Cybersecurity and Fragility

Cybersecurity is another major component.

An infrastructure system may have:

• excellent market competition but poor cyber resilience; or
• excellent cybersecurity but excessive economic concentration.

The two risks should therefore be measured separately.

A comprehensive index should distinguish:

Operational fragility

Risk of accidental or technical failure.

Cyber fragility

Risk of malicious disruption.

Competitive fragility

Risk that dominant infrastructure providers can exclude competitors.

Institutional fragility

Risk that government or public services depend excessively on private infrastructure.

Systemic fragility

Risk that one failure propagates across multiple markets.

19. Why Ordinary HHI Is Insufficient

A major limitation of conventional concentration measures is that they measure market structure, not necessarily systemic dependency.

Consider:

Market A: four cloud providers with relatively equal shares.

But suppose:

• all four depend upon one semiconductor supplier;
• all rely on one DNS infrastructure;
• all use the same authentication infrastructure; and
• 70% of government applications use the same identity provider.

The market may appear competitive according to HHI while the overall digital system remains highly fragile.

Therefore:

Infrastructure concentration must be analysed vertically and horizontally.

20. Policy and Regulatory Remedies

Where a fragility assessment identifies serious competition or systemic risks, possible remedies include:

Structural remedies

• divestiture;
• separation of infrastructure and downstream operations;
• restrictions on acquisitions.

Behavioural remedies

• non-discriminatory access;
• interoperability;
• data portability;
• transparency;
• fair pricing;
• API access.

Resilience remedies

• redundancy requirements;
• multi-provider architecture;
• disaster recovery requirements;
• backup infrastructure.

Competition remedies

• prohibition of exclusivity;
• anti-foreclosure rules;
• self-preferencing restrictions;
• interoperability obligations;
• switching assistance.

21. Key Legal Principles Emerging From the Case Law

The cases collectively support several important principles.

Principle 1 — Control of infrastructure can create market power

United Brands and infrastructure-related Article 102 jurisprudence demonstrate the importance of economic dependence.

Principle 2 — Indispensability matters

Bronner establishes the demanding importance of genuine indispensability in essential-facility situations.

Principle 3 — Upstream control can produce downstream foreclosure

Commercial Solvents demonstrates the significance of bottleneck inputs.

Principle 4 — Interoperability can be competitively significant

Microsoft illustrates the importance of interoperability information in platform markets.

Principle 5 — Telecommunications infrastructure deserves special scrutiny

Slovak Telekom and Deutsche Telekom demonstrate the competitive importance of network infrastructure.

Principle 6 — Digital ecosystems can create cross-market leverage

Google Shopping and Google Android demonstrate how control over a digital gateway can influence neighbouring markets.

22. Critical Limitation

A fragility index must not become a substitute for legal analysis.

A high index does not necessarily mean:

• the undertaking is dominant;
• access must legally be provided;
• a refusal is abusive;
• concentration is unlawful; or
• structural separation is justified.

The index should instead operate as an early-warning and prioritisation mechanism.

The strongest approach is therefore:

Market Power Analysis + Infrastructure Dependency Analysis + Fragility Index + Conduct Analysis + Effects Analysis

23. Conclusion

Digital Infrastructure Fragility Indices provide a useful framework for analysing the vulnerability of modern digital economies to concentration, dependency, exclusion, technological failure and cascading disruption.

Traditional competition law generally asks:

Who possesses market power and how is that power being exercised?

A fragility-oriented approach adds another question:

What happens to competitive markets if this infrastructure provider fails, excludes rivals, restricts access, changes interoperability conditions, or becomes unavoidable?