How to spot corruption

Corruption is rarely announced. It hides in routine paperwork: a tender, a grant application, a change to a contract, a company registered in a distant jurisdiction. But the schemes that investigators uncover tend to leave similar traces, and many of those traces are visible to anyone who knows where to look.

Specialists call these traces red flags. A red flag is an indicator that a process deserves a closer look. It is not proof that a crime was committed, and there are often innocent explanations. A study carried out for the European Commission and the European Anti-Fraud Office (OLAF) catalogued dozens of such indicators in public procurement alone, and OLAF has published its own collection of red flags and best practices for fraud in public procurement. In 2024 the Open Contracting Partnership published a guide to using procurement data to detect them at scale.

This page explains the most common patterns, in plain language, and what to do if you notice one. It is written for citizens, journalists, civil servants and business owners, not only for auditors.

Public procurement, where governments buy goods, works and services, is one of the areas most exposed to corruption because it involves large sums and discretionary decisions. The patterns behind the warning signs above are usually one of the following.

• Bid rigging. Bidders agree in advance who will win. They may submit “cover bids” that are deliberately too high, take turns winning, or withdraw at the last moment.
• Kickbacks. An official favours a supplier in exchange for money or other benefits. The inflated price of the contract often pays for the bribe.
• Tailored rules. The technical requirements are written so that only one company can meet them, or the evaluation criteria are changed after the offers have been opened.
• Conflict of interest. The person who prepares or approves the tender has a hidden personal or financial link with a bidder.

Much of the evidence is public. In the EU, tenders above certain thresholds must be published in the Tenders Electronic Daily (TED) database, and many countries operate national portals that show who won, for how much and with how many bidders. Researchers use the share of contracts that attract only one bidder as a proxy for market access being restricted, and a persistently high share in a region or institution is a reason to ask questions.

A practical routine: read the notice, check how long bidders had to prepare, see how many offers were received, compare the final price with the estimate, and look at whether the contract was later amended. If several of these look unusual at once, the case is worth following.

Not all corruption involves cash. A decision can be corrupted by a relationship: an official who awards a grant to a company owned by a relative, a minister who regulates the sector in which they recently worked, or a manager who holds shares in a supplier without declaring them. Such conflicts of interest are not always illegal, but undeclared ones are a classic red flag.

Watch for unexplained links between decision-makers and beneficiaries: the same names appearing in company records and in public office, newly founded companies winning large contracts, or firms with no staff and no track record receiving money for “consultancy”. Asset and interest declarations of public officials, where they are published, are a useful starting point.

Ownership structures can also hide the real beneficiary. A chain of companies in several countries, nominee directors or an address shared by hundreds of firms make it hard to see who profits. Registers of beneficial owners exist across the EU, but how much of them the public can see varies by country, so access is part of the story.

To see how red flags combine, consider an invented example. A municipality announces a tender for renovating a school. The notice appears only on a local website, and offers must be submitted within a week. The technical specification requires a particular brand of windows that only one local firm supplies. Only that firm bids. It wins at a price 30% above the municipality’s own estimate.

Three months later the contract is amended to add “unforeseen” work, and the price increases again. The owner of the winning firm turns out to be a cousin of a member of the evaluation committee, who did not declare the relationship. None of these facts proves a crime on its own. A short deadline can be an honest mistake, a specific brand can be justified, and a family tie is not itself illegal. But five signs at once, and an undeclared relationship, are exactly the kind of picture that auditors flag for further review.

This is how most real cases begin: not with a confession or a smoking gun, but with a pattern that someone noticed and was willing to question.

Money from the EU budget is spent in two ways: directly by EU institutions, and, for the most part, through national and regional authorities. Both routes attract fraud. The European Public Prosecutor’s Office (EPPO) reported 981 active VAT and customs fraud cases at the end of 2025, with estimated damage of EUR 45 billion, and 2,450 cases of fraud against EU expenditure with estimated damage of EUR 18.67 billion. It was also handling 512 cases linked to the Recovery and Resilience Facility.

Common patterns in grant and subsidy fraud include inflated or invented costs, activities that were never carried out, the same expense claimed from several funding programmes, and “consultancies” that exist only on paper. For VAT, a typical scheme involves a chain of companies in different countries in which one of them collects VAT and disappears, while others claim it back. The invoices circulate, the goods may be real or not, and the budget loses money.

Warning signs for the public include projects that are announced but never visibly progress, very similar applications submitted by connected companies, and firms that appear shortly before a funding call and vanish afterwards. If you want to see how such schemes look in practice, the Calculator’s case archive describes concrete investigations, with sources.

Corruption also appears at a smaller scale, in daily contact with the state. A request for an “extra fee” for a service that should be free, pressure to skip paperwork in exchange for money, a permit that moves quickly only after a personal favour, or an official whose lifestyle does not match their salary: these are all warning signs.

The 2024 Eurobarometer found that 27% of Europeans feel personally affected by corruption in their daily lives. Not every case will be criminal, but a pattern of “unofficial payments” is a sign that something in the system does not work.

You do not need access to secret files to ask useful questions. Here are some that journalists, researchers and engaged citizens use when looking at public spending.

• How many companies bid, and how did the winning price compare with the estimate?
• Were the requirements objectively necessary, or do they describe one particular product?
• How much time did bidders have, and where was the tender advertised?
• Was the contract changed after the award, and by how much?
• Who owns the winning company, and does any owner or manager have ties to the awarding body?
• Does the same company win repeatedly from the same institution?
• Is there evidence that the work was actually delivered, and does it match what was paid for?

Asking these questions is legitimate. In many countries you can request public documents under access-to-information laws, and public bodies have a duty to explain how they spend public money. A clear and quick answer is a good sign, and evasive answers are another signal worth noting.

Several open resources make it possible to check things yourself. The EU’s Tenders Electronic Daily publishes notices and awards for public contracts above the thresholds set by EU rules. Many Member States run national procurement portals with data on bids and winners, and some publish data in open formats that researchers can analyse in bulk, as the Open Contracting Partnership encourages. Company registers show owners and directors, subject to national rules, and many officials publish asset and interest declarations.

Data alone does not prove corruption, and automated indicators produce false alarms. The best results come from combining data with local knowledge: someone who knows the market, the institution and the people can tell the difference between an oddity and a pattern. If you work with data, document your method, report your findings with caution and give the parties concerned the chance to respond.

If you notice a pattern that worries you, a few steps are sensible. Write down what you saw, with dates, names of institutions and the documents where it appears. Keep copies of public documents. Check whether the information is already public, for example in a procurement portal or a company register. Avoid confronting the people involved, and do not spread allegations that you cannot support.

Then report your concerns to the right body. Where to go, and how EU law protects people who raise a concern in good faith, is explained on our page Reporting corruption without fear.