Competition Law and Cartel Screening Methods in Denmark

1. Introduction

Cartel screening in Denmark refers to the methods used to identify patterns suggesting collusion between competing undertakings, particularly price-fixing, market sharing, bid-rigging, output restrictions and unlawful exchange of competitively sensitive information.

The Danish framework is principally based on Section 6 of the Danish Competition Act, which prohibits agreements, decisions and concerted practices that have the object or effect of restricting competition. The provision corresponds broadly to Article 101 TFEU. Danish enforcement is undertaken principally by the Danish Competition and Consumer Authority (DCCA/Konkurrence- og Forbrugerstyrelsen), with the Competition Council and courts playing important roles.

The Danish approach is notable because it combines:

1. Economic and statistical screening;
2. Digital and computational screening of procurement data;
3. Whistleblower and leniency information;
4. Tender-level red-flag analysis;
5. Document and communication analysis;
6. Market intelligence and complaint-based detection;
7. Inspections/dawn raids and evidence gathering; and
8. Traditional legal and economic investigation after a screen produces a lead.

The DCCA has expressly developed Bid Viewer, a computational tool designed to identify suspicious bidding patterns in public procurement. The Authority describes computational screening as a means of flagging tenders or firms for subsequent traditional investigation—not as proof of an infringement by itself.

2. Legal Framework

Section 6 of the Danish Competition Act

Section 6 prohibits agreements, decisions and concerted practices that restrict competition.

Typical cartel conduct includes:

• price fixing;
• coordination of discounts;
• market or customer allocation;
• bid rigging;
• output limitation;
• exchange of strategically sensitive information;
• coordinated purchasing arrangements that eliminate competition; and
• other forms of horizontal coordination.

The Danish authority specifically identifies price fixing, market sharing and bid rigging as common forms of cartel behaviour.

For serious restrictions, particularly classical cartels, the principal analytical question is often whether the conduct has an anti-competitive object, rather than requiring detailed proof of actual market effects.

3. What Is Cartel Screening?

Cartel screening is different from proving a cartel.

A screen identifies an unusual pattern such as:

unusually similar bids → statistical anomaly → possible collusion → further investigation → documentary/electronic evidence → legal assessment.

Thus, screening is essentially an early-warning mechanism.

The Danish Authority's procurement-screening work expressly treats computational screens as the first step before a traditional case process.

Important distinction

4. Major Cartel Screening Methods in Denmark

A. Statistical Screening of Tender Prices

One of the most important Danish techniques concerns public procurement.

Authorities can examine:

• winning bid;
• losing bids;
• bid dispersion;
• price differences;
• number of bidders;
• frequency of participation;
• winning patterns;
• geographic patterns;
• tender-specific price movements.

An abnormal pattern may suggest that bidders are coordinating rather than independently competing.

Example

Suppose five companies repeatedly participate in municipal tenders:

• Company A wins Tender 1;
• Company B wins Tender 2;
• Company C wins Tender 3;
• the same firms submit unusually close bids;
• losing firms subsequently win elsewhere.

A repeated pattern can trigger additional examination.

The DCCA's Bid Viewer uses statistical indicators derived from bids and incorporates them into more sophisticated screening models.

5. Bid Rotation Screening

Bid rotation occurs where competitors effectively take turns winning contracts.

A screening system may examine:

• sequence of winners;
• frequency of victories;
• geographic allocation;
• customer allocation;
• changes in winning firms;
• relationship between winning and losing bids.

For example:

A pattern of this type is not automatically unlawful. However, if combined with unusually similar prices, communications, common documents or other evidence, it can become a significant investigative lead.

6. Bid Similarity Analysis

The DCCA identifies similarities between bids as an important warning sign.

Potential indicators include:

• identical calculations;
• identical pricing structures;
• identical formatting;
• identical documents;
• unusual identical wording;
• identical spelling mistakes;
• identical mathematical errors.

The DCCA specifically advises procurement bodies to look for highly similar bids and other common characteristics.

This method is particularly useful because a cartel may leave linguistic and technical fingerprints even when the participants attempt to conceal their coordination.

7. Metadata Screening

Modern cartel screening increasingly extends beyond the visible contents of tender documents.

Investigators may examine:

• document creation dates;
• authorship information;
• computer-generated metadata;
• document revision history;
• file properties;
• common templates;
• electronic editing records.

For example, if apparently independent bids from three competitors were created or edited by the same person or contain unusual common metadata, this may warrant further investigation.

The DCCA expressly identifies metadata anomalies as a potential bid-rigging warning sign.

8. Machine Learning and Artificial Neural Networks

Denmark has developed an advanced computational approach to cartel detection.

The DCCA explains that its procurement-screening methodology includes:

1. statistical indicators;
2. machine-learning models; and
3. artificial neural-network approaches.

These models can be trained using datasets containing known competitive and potentially collusive tenders.

The objective is not to allow an algorithm to determine liability but to identify tenders and companies that deserve closer examination.

Legal significance

Machine learning may identify:

"This tender looks unusual."

It cannot, without additional evidence, establish:

"These companies entered into an unlawful cartel."

That distinction is fundamental to due process.

9. Price-Variance Screening

Another method involves examining whether prices behave as expected in a competitive market.

Indicators may include:

• unusually small price differences;
• unusually large price differences;
• unexplained simultaneous price increases;
• identical surcharges;
• disappearance of normal competitive variation;
• abnormal price stability.

This can be particularly useful in industries where independent firms would normally be expected to have substantially different costs or pricing strategies.

10. Parallel Price-Movement Analysis

Cartel screening can also examine whether competing firms change prices in an unusually coordinated manner.

For example:

Firm A raises prices → Firm B immediately adopts the same increase → Firm C follows.

Parallel price movements alone are not sufficient proof of a cartel, because prices may move together for legitimate reasons such as common input-cost increases.

Accordingly, price screening must normally be combined with other evidence.

The Broste Copenhagen matter illustrates the importance of distinguishing ordinary parallel pricing from actual coordination: the Danish authority found evidence of coordination concerning a freight surcharge and other pricing elements.

11. Information-Exchange Screening

Cartels may operate through information exchange without an explicit written price-fixing agreement.

Screening may therefore examine:

• competitor communications;
• trade-association exchanges;
• emails;
• meeting records;
• shared pricing information;
• future pricing information;
• customer allocation information.

The HUGO BOSS Nordic/Ginsborg proceedings are an important Danish example involving exchange of information between competitors. Ginsborg subsequently applied for leniency and supplied information that enabled the authorities to establish an infringement.

12. Whistleblower and Complaint-Based Screening

Not all cartel detection is algorithmic.

The Danish system also relies on:

• employee reports;
• competitor complaints;
• customer complaints;
• procurement officials;
• anonymous tips;
• leniency applications.

The DCCA expressly allows suspected cartel activity to be reported anonymously.

This is particularly important because employees and participants may possess information that cannot be detected through economic datasets.

13. Leniency as a Cartel-Detection Mechanism

Leniency is one of the most powerful methods of uncovering secret cartels.

Under the Danish system, a qualifying first applicant can potentially obtain immunity from fines and imprisonment where the statutory conditions are satisfied, including providing information capable of enabling an inspection or establishing an infringement.

Leniency therefore performs two functions:

Detection function

It supplies evidence of a cartel.

Destabilisation function

It creates an incentive for cartel members to defect from the cartel.

The Danish Competition Act also contains mechanisms dealing with summary leniency applications where the European Commission is dealing with a cartel affecting more than three EU Member States.

14. Dawn Raids and Digital Evidence

Where preliminary information warrants further action, Danish authorities can use investigation powers including inspections.

A cartel investigation may involve examination of:

• emails;
• computers;
• mobile devices;
• documents;
• accounting information;
• internal communications;
• meeting records;
• tender files.

The DCCA describes control inspections or dawn raids as an important part of its enforcement work.

Screening therefore functions as a bridge between economic evidence and traditional investigative evidence.

15. Cross-Tender Network Analysis

A sophisticated screening approach examines relationships across multiple tenders.

Instead of asking:

"Does Tender X look suspicious?"

the authority can ask:

"Do Companies A, B, C and D exhibit repeated relationships across 500 tenders?"

Potential variables include:

• common participation;
• repeated winning relationships;
• geographic patterns;
• subcontracting relationships;
• bid withdrawal;
• repeated losing bids;
• common prices;
• common documentation.

This can reveal cartel structures that would remain invisible if each procurement exercise were examined separately.

16. Sector-Specific Screening

Cartel screening can be particularly effective where the market has:

• few competitors;
• repeated tenders;
• standardized products;
• transparent prices;
• stable customers;
• repeated interactions.

The DCCA reports that its bid-rigging investigations have included construction, demolition and plumbing industries and states that approximately 40 companies had been fined in bid-rigging cases over the preceding decade at the time of its Bid Viewer publication.

17. Six Important Danish Case Laws / Enforcement Cases

1. Christoffersen & Knudsen A/S – VVS Bid Coordination

The company was fined DKK 575,000, while a leading employee was personally fined DKK 25,000, for coordination of bids relating to VVS work on the Enebærhaven construction project.

The investigation began following a tip, demonstrating the continuing importance of human intelligence alongside statistical screening.

Another company, Fredensborg VVS-Teknik, had previously received a DKK 1 million fine concerning coordinated bids on five construction projects.

Screening significance

This case illustrates:

• whistleblower/tip-based detection;
• tender analysis;
• bid coordination;
• construction-sector cartel risks;
• transition from preliminary information to formal investigation.

2. Broste Copenhagen – Price Coordination

Broste Copenhagen admitted participation in a cartel involving coordination of prices with a competitor.

The conduct included coordination concerning a Covid-19-related freight surcharge and price increases during 2021.

The company accepted a fine of DKK 6 million, following a higher calculated amount and a reduction reflecting cooperation with the investigation.

Screening significance

The case demonstrates the importance of:

• monitoring unusual common surcharges;
• identifying coordinated price changes;
• examining competitor communications;
• distinguishing independent parallel conduct from actual coordination.

3. Hübsch – Price and Information Coordination

The Danish Competition Council found that Hübsch coordinated prices and exchanged price information with competitor Broste Copenhagen.

The coordination concerned, among other things, a Covid-19 fee and price increases.

The case was referred to the Maritime and Commercial High Court for a civil fine.

Screening significance

The case demonstrates why screening should not be restricted to final consumer prices.

Investigators should also examine:

• surcharge introduction;
• timing of price changes;
• competitor communications;
• exchange of future pricing information.

4. Ginsborg / HUGO BOSS Information-Exchange Case

The Ginsborg proceedings concerned information exchange between competitors.

Importantly, Ginsborg approached the authorities in 2018 with a leniency application and provided information that enabled the authorities to establish an infringement.

Screening significance

This is an important example of the relationship between:

internal participant evidence → leniency → investigation → enforcement.

It demonstrates that computational screening is only one component of a broader cartel-detection system.

5. ECIT Account A/S – Nightclub Cartel

In 2025, the Maritime and Commercial High Court imposed a DKK 20 million fine on ECIT Account for facilitating a long-running market-sharing arrangement involving nightclubs.

The case concerned an agreement under which nightclubs were restricted from opening establishments in one another's geographic areas. ECIT Account helped formalise and maintain the arrangement and participated in meetings where market sharing was discussed.

Screening significance

The case is particularly important because cartel screening must also detect facilitators and intermediaries, not merely the competitors receiving the economic benefit.

Potential screening indicators include:

• unusual territorial restrictions;
• customer/geographic allocation;
• common contractual documents;
• third-party involvement;
• repeated meetings concerning market allocation.

6. Tartan Pub / Danish Nightclub Cartel

Tartan Pub was among several companies sanctioned for participating in the nightclub market-sharing cartel.

The businesses received fines ranging from approximately DKK 57,000 to DKK 111,000, with the lower amounts influenced by the exceptionally low turnover during the Covid-19 closure period and cooperation in resolving the cases.

Screening significance

The case illustrates how authorities can examine:

• geographical market allocation;
• restrictions on establishment;
• relationships among competitors;
• common purchasing structures;
• repeated patterns over several years.

18. GVCO / Eurostar – Consortium and Bid Competition

The Danish litigation concerning GVCO and Eurostar is particularly relevant to cartel-screening analysis because the Competition Council considered a consortium agreement between competitors in the context of a procurement.

The underlying issue included allegations of price fixing and market division in connection with the preparation, submission and performance of bids. The Danish Supreme Court materials discuss Section 6 and the distinction between legitimate cooperation and agreements restricting competition.

Screening significance

This demonstrates an important limitation:

Not every joint bid is a cartel.

A screening system must distinguish legitimate consortium arrangements from agreements whose purpose or effect is to eliminate competition between otherwise competing firms.

19. Cartel Screening Red Flags in Danish Procurement

The Danish authority identifies a number of practical indicators.

Documentary indicators

• identical wording;
• identical spelling errors;
• identical calculations;
• identical templates;
• common formatting;
• unusual document similarities.

Metadata indicators

• same document creator;
• common editing history;
• one bidder modifying another bidder's document;
• unusual electronic links between bidders.

Pricing indicators

• identical prices;
• suspiciously close bids;
• unexplained price patterns;
• repeated price differences;
• unusual bid rotation.

Participation indicators

• competitors repeatedly declining tenders;
• firms participating only in selected geographical areas;
• predictable winner patterns;
• unexplained subcontracting relationships.

The DCCA specifically recommends examining both individual bids and patterns across several procurements.

20. Bid Viewer: Denmark's Computational Screening Model

The Danish Bid Viewer methodology is particularly significant for modern competition law.

Its basic structure can be represented as:

Procurement database

↓

Data cleaning

↓

Statistical indicators

↓

Machine-learning analysis

↓

Suspicious tender/company identified

↓

Human review

↓

Additional information gathering

↓

Traditional competition investigation

↓

Legal assessment

The DCCA expressly states that computational screening is designed to complement traditional investigative methods.

21. Evidentiary Limits of Cartel Screening

A statistical anomaly does not equal a cartel.

For example:

Three companies submit almost identical bids.

This may be suspicious, but legitimate explanations could include:

• common input prices;
• standardized tender specifications;
• common industry cost structures;
• use of the same publicly available pricing formula;
• legitimate subcontracting;
• identical technical requirements.

Therefore, screening should generally be treated as probabilistic evidence or investigative intelligence, rather than conclusive proof.

22. Screening Versus Legal Proof

A useful analytical model is:

Stage 1 — Detection

"Is something unusual happening?"

Stage 2 — Hypothesis

"Could this be explained by collusion?"

Stage 3 — Investigation

"What communications, documents or conduct exist?"

Stage 4 — Legal assessment

"Does the conduct constitute an agreement, concerted practice or other infringement?"

Stage 5 — Enforcement

"Are the evidentiary and procedural requirements satisfied?"

This distinction protects against false positives generated by purely statistical methods.

23. Relationship Between Competition Economics and Digital Forensics

Modern Danish cartel enforcement therefore combines two different evidence streams.

Economic evidence

• bid dispersion;
• price variance;
• winner rotation;
• market shares;
• tender participation;
• price movements.

Digital/documentary evidence

• emails;
• metadata;
• file creation;
• messages;
• meeting records;
• spreadsheets;
• internal pricing instructions.

The strongest cases can arise where both streams point in the same direction.

24. Role of Artificial Intelligence

AI and machine learning can significantly improve cartel detection because authorities may have access to thousands or millions of procurement observations.

Potential applications include:

• anomaly detection;
• clustering of firms;
• prediction of suspicious bid patterns;
• identification of unusual bidder relationships;
• document similarity analysis;
• network analysis;
• automated extraction of pricing patterns.

However, AI should generally be used as a screening and investigative-support tool, rather than as an autonomous legal decision-maker.

The Danish Bid Viewer experience provides a concrete example of computational methods being integrated into competition enforcement.

25. Practical Compliance Implications for Danish Businesses

Companies participating in Danish procurement should maintain:

1. independent pricing decisions;
2. documented pricing methodologies;
3. competition-law training;
4. restrictions on competitor communications;
5. controls over participation in trade associations;
6. clean tender documentation;
7. appropriate email and messaging policies;
8. procedures for responding to competitor contacts;
9. internal reporting mechanisms; and
10. a system for seeking legal advice where competitor interaction creates risk.

Particular caution is necessary regarding:

• future prices;
• discounts;
• customers;
• geographic territories;
• bid intentions;
• tender strategies;
• production capacity.

26. Overall Analytical Framework

The Danish cartel-screening system can be summarized as follows:

Complaints / Leniency / Whistleblowers

↓

Procurement and Market Data

↓

Statistical Screening

↓

Bid Similarity / Metadata Analysis

↓

Machine Learning / Neural Networks

↓

Suspicious Tender or Firm

↓

Human Review

↓

Information Requests / Interviews

↓

Digital Evidence / Dawn Raid

↓

Legal and Economic Assessment

↓

Competition Council / Court Proceedings

↓

Fine, Civil Enforcement or Other Remedy

The DCCA's current procedural guidance expressly describes competition cases as progressing from initial screening, through information gathering and analysis, to hearing of the parties, Competition Council consideration and possible court proceedings.

27. Conclusion

Denmark has developed a relatively sophisticated multi-layered cartel-screening model. Traditional tools such as complaints, leniency, interviews, document examination and dawn raids remain important, but they are increasingly supplemented by statistical analysis, procurement-data screening, machine learning, artificial neural networks, bid-similarity analysis and metadata examination.

The Danish Bid Viewer is particularly significant because it demonstrates how computational techniques can be used to identify suspicious procurement patterns at scale. At the same time, Danish enforcement practice shows that a statistical screen is only the beginning: actual enforcement requires a subsequent investigation capable of establishing the relevant agreement, concerted practice or other infringement.

The principal lesson is therefore:

Cartel screening identifies suspicious conduct; it does not itself establish cartel liability.

The most effective Danish approach combines economic anomalies + documentary/digital evidence + leniency or whistleblower information + traditional investigation + legal assessment under Section 6 of the Danish Competition Act and Article 101 TFEU.

Key cases for examination

1. Christoffersen & Knudsen A/S – VVS bid coordination
2. Broste Copenhagen – price coordination
3. Hübsch – price and information exchange
4. Ginsborg / HUGO BOSS – information exchange and leniency
5. ECIT Account A/S – nightclub market-sharing cartel
6. Tartan Pub / nightclub cartel
7. GVCO / Eurostar – consortium and procurement competition

These cases collectively illustrate the major detection channels: tips, leniency, tender screening, information-exchange analysis, market-sharing analysis, documentary evidence and computational detection.