Suspected business cartels are difficult to investigate because the visible result—similar prices, repeated winners or unusually stable market shares—can have innocent explanations. A defensible investigation therefore starts with a narrow hypothesis and tests it against public evidence. It does not treat parallel conduct as proof of an agreement.
In competition law, cartel conduct commonly includes price fixing, bid rigging, market or customer sharing, and agreements to restrict output. The European Commission’s antitrust and cartels overview explains the legal framework, while the UK Competition and Markets Authority describes the principal types of anti-competitive activity. Those definitions should determine the research question before documents are collected.
Define the market and allegation
First identify the product or service, geographic market, time period and suspected mechanism. “Several companies charge the same price” is too broad. A testable question is whether named suppliers coordinated bids for a defined class of public contracts between specific dates.
Create a chronology of tenders, price changes, ownership events, trade-association meetings and personnel movements. Preserve the original files and URLs, record retrieval dates and separate confirmed facts from allegations. Trider’s guide to data triangulation in beneficial-ownership investigations explains why no single registry should be treated as conclusive.
Collect comparable data
For procurement research, download tender notices, specifications, bidder lists, bid values, award decisions, contract amendments and delivery records. Standardise names and currencies before comparing results. For private markets, use published price lists, archived websites, annual reports, market studies and regulator decisions.
Look for patterns such as bid rotation, losing bids clustered just above the winner, identical errors or formatting, unexplained subcontracting between rivals, geographic allocation, sudden withdrawal from customers, or prices moving together without a corresponding cost shock. Trider’s framework for investigating procurement deals can help organise the documentary trail.
Test innocent explanations
Market structure can produce parallel behaviour without collusion. Rivals may face the same energy, labour, tax or currency movements; use a common price index; sell standardised products; or independently follow a transparent market leader. The US Department of Justice’s Antitrust Division resource manual cautions that identical prices alone are not evidence of a conspiracy.
Compare the suspected pattern with costs, demand, capacity and regulatory changes. Test whether it persists across products and regions, whether new entrants behave differently, and whether the pattern changes after meetings or communications. A strong finding survives plausible alternative explanations.
Seek evidence of coordination
Structural screens identify where to look; they rarely establish an agreement. Stronger evidence may include communications between competitors, meeting records, shared bid documents, instructions to accommodate a rival, or testimony corroborated by records. Public investigators may have compulsory powers that journalists and private researchers do not. Researchers should never impersonate officials, trespass, obtain data unlawfully or alert suspected parties in ways that could endanger sources or evidence.
Public-procurement reporting can supply leads but must be labelled carefully. For example, Malta News Online’s reporting on Malta Gaming Authority direct orders provides procurement context; the existence of direct awards or concerns about them does not by itself establish cartel conduct.
Build an evidence matrix
For every proposition, record the source, date, reliability, corroboration and alternative explanation. A useful matrix distinguishes:
- Market indicators: concentration, barriers to entry and transparency.
- Behavioural indicators: bid rotation, pricing patterns or customer allocation.
- Communication evidence: meetings, messages or shared documents.
- Contrary evidence: cost changes, independent strategy or data gaps.
Where leaked or confidential material is involved, authenticate it and understand its limits. The same discipline described in assessing leaked compliance documents applies: metadata, provenance and independent corroboration matter more than a dramatic excerpt.
Report findings proportionately
Before publication, send precise questions and allow meaningful time for replies. Distinguish evidence of suspicious patterns from proof of an unlawful agreement. Avoid declaring criminal or civil liability unless a competent authority or court has done so, and link to the underlying decisions where possible.
A credible cartel investigation is reproducible. Another researcher should be able to follow the dataset, understand the assumptions and see why alternative explanations were accepted or rejected. That transparency makes the work useful to regulators, affected customers and the public without overstating what the evidence can prove.