Short answer
Separate four warning signs. An apparently abnormally low price requires explanation and inter partes assessment under Article 69 of Directive 2014/24. If unlawful environmental, social or labour savings cause the low price, rejection is mandatory; other established breaches may support non-award or exclusion under national transposition.
Under Regulation 2022/2560, tenderers notify or declare foreign financial contributions through the authority, while the Commission decides distortion. Suspicion alone cannot become an abnormally-low finding.
For suspected collusion, plausible indications may support exclusion, but affiliation or parallel pricing is insufficient alone. Examine evidence, bid autonomy, explanations and self-cleaning, then give a proportionate reasoned decision. Document each route separately.
The investigation file should identify the objective trigger, the rule and national option relied on, the evidence requested, who has decision-making power, and why the outcome is necessary. Tenderer participation, confidentiality and equal treatment apply throughout; a general sense that a bid is risky cannot replace the relevant statutory test.
Start with the trigger, not the desired outcome
A low price can reflect efficiency, unlawful savings, State aid, a foreign subsidy or coordination. Record the indicator, legal route, evidence and decision-maker.
Equal treatment, transparency and proportionality under Article 18(1) govern every route. Apply the same methodology to comparable tenders, protect confidential information and preserve an audit trail. National transposition remains essential because Member States implement Article 57's optional grounds and procedural rules.
An apparently abnormally low tender must be explained
EU law does not impose one universal mathematical threshold for identifying an abnormally low tender. A national formula or procurement-document method can flag a tender, but it cannot replace the substantive assessment of price or cost in relation to the works, supplies or services.
Article 69(1) states:
“Contracting authorities shall require economic operators to explain the price or costs proposed in the tender where tenders appear to be abnormally low in relation to the works, supplies or services.” —
The request should identify doubtful components clearly enough for a meaningful response. Article 69(2) covers economics, technical solutions, favourable conditions, originality, legal and subcontracting compliance, and possible State aid.
The authority must consult the tenderer and assess the evidence. It may reject only where the explanation does not satisfactorily account for the low price or cost. Test quantities, staffing, wages, productivity, supplies and risk against the technical offer. A low margin is not automatically unlawful if performance and compliance are credible.
Earlier cases support the dialogue now stated in Article 69. SAG ELV Slovensko, Case C-599/10, rejected a supposed freedom to skip clarification. Veridos, Case C-669/20, applying the parallel defence-procurement rule, confirmed that suspicion requires verification using relevant tender and contract material.
Two 2025 General Court judgments sharpen that process for EU-body procurement. NTT Data Belgique, T-161/24, describes a prima-facie trigger followed by detailed examination, effective tenderer explanation and a decision giving the broad outlines of the analysis. UniSystems Luxembourg, T-750/22, applied the same two-stage approach where compliance with Member State minimum-wage rules was disputed. They concern EU institutional rules, but reinforce the Article 69 sequence; they do not create a new national-procurement exclusion ground.
Labour, social and environmental compliance changes the result
Article 18(2) requires Member States to ensure compliance during contract performance:
“Member States shall take appropriate measures to ensure that in the performance of public contracts economic operators comply with applicable obligations in the fields of environmental, social and labour law established by Union law, national law, collective agreements or by the international environmental, social and labour law provisions listed in Annex X.” —
Identify the applicable obligation precisely, such as a statutory wage, binding collective agreement, working-time rule or listed convention. Test staffing and subcontracting against it rather than relying on a general impression that labour costs look low.
The consequences differ by stage:
- under Article 69(3), the authority must reject a tender established to be abnormally low because of Article 18(2) non-compliance;
- under Article 56(1), it may decide not to award the most economically advantageous tender where it has established non-compliance;
- Article 57(4)(a), as implemented nationally, permits or may require exclusion where the authority demonstrates a violation by appropriate means;
- Articles 70 and 71 support disclosed performance conditions and oversight of subcontractors.
Exclusion still requires the applicable national rule, a fair factual inquiry and proportionality. In TIM, Case C-395/18, the Court held that Article 57 could cover a breach by a named subcontractor, but precluded automatic exclusion of the tenderer without an individual assessment and the Article 57(6) reliability mechanism. Evidence of corrective action may therefore matter unless a binding final exclusion prevents self-cleaning.
State aid and foreign subsidies are not the same inquiry
Article 69(4) addresses State aid granted by an EU Member State. A tender found abnormally low because of State aid may be rejected on that ground alone only after consultation and where the tenderer cannot prove the aid compatible with the internal market within a sufficient time. The authority must inform the Commission if it rejects on that basis.
Financial support from a non-EU country is governed separately by the Foreign Subsidies Regulation, Regulation (EU) 2022/2560 (FSR). A foreign financial contribution is not automatically a foreign subsidy, and a subsidy is not automatically distortive. The Commission, not the contracting authority, performs that assessment.
Prior notification applies where the contract or framework is at least EUR 250 million and the tenderer, relevant group, main subcontractors and main suppliers received at least EUR 4 million per third country over three years. Lots add a EUR 125 million threshold. Otherwise the operator declares contributions non-notifiable. Regulation 2023/1441 supplies the forms.
The authority must state the filing obligation, receive the notification or declaration and transfer it to the Commission without delay. It may request a missing document within ten working days; an ultimately missing filing makes the tender irregular. If it suspects a subsidy despite a declaration, Article 29(7) requires an alert to the Commission and sets this boundary:
“the contracting authority or contracting entity shall not perform an assessment of whether a tender is abnormally low where such an assessment would be initiated on the suspicions indicating a possible presence of foreign subsidies alone.” —
The Commission may require ad hoc notification below thresholds. Preliminary review normally lasts 20 working days, extendable by ten; in-depth review up to 110, extendable by 20. Article 32's award standstill applies. The Commission may clear, accept commitments or prohibit award; prohibition requires rejection.
Suspected collusion requires evidence, inquiry and independence
Article 57(4)(d) permits exclusion, or requires it where national law so provides, where there are “sufficiently plausible indications” that an operator entered agreements aimed at distorting competition. A final competition-law infringement decision is not always required. In Landkreis Aichach-Friedberg, Case C-416/21, the Court confirmed that the ground covers, but is not limited to, agreements prohibited by Article 101 TFEU.
Identical unusual errors, bid rotation, coordinated pricing, shared preparation or suspicious subcontracting can be warning signs, not proof. Corporate links likewise do not justify automatic exclusion.
In Specializuotas transportas, Case C-531/16, the Court stated the operational duty:
“the contracting authority, when it has evidence that calls into question the autonomous and independent character of the tenders submitted by certain tenderers, is obliged to verify, requesting, where appropriate, additional information from those tenderers, whether their offers are in fact autonomous and independent.” —
Objective and consistent indicia can prove coordination; direct evidence is not indispensable. But the authority should give affected operators a fair opportunity to address the evidence without disclosing competitors' confidential material. If bids were influenced by their relationship and were not autonomous, they cannot receive the award. If an exclusion ground is established, Article 57(6) requires assessment of admissible self-cleaning evidence. Vossloh Laeis, Case C-124/17, confirms that proportionate cooperation with the contracting authority may be required to assess restored reliability.
A defensible investigation file
For each suspect tender:
- Record the objective trigger and separate Article 69, Article 18(2), FSR and collusion questions.
- Identify the EU rule, national transposition and competent authority.
- Request focused explanations and test documents, calculations, staffing, subcontracting and corporate links consistently.
- Send FSR filings and suspicions to the Commission and coordinate lawfully with other competent bodies.
- Consider proportionality and admissible self-cleaning evidence.
- Give reasons without exposing protected information, preserving the record for review and monitoring.
Conclusion
EU procurement law does not authorise a single discretionary “suspicious bid” rejection. An apparently abnormally low tender requires explanation and evidence-based consultation. An unlawful labour, social or environmental saving can make rejection mandatory. Foreign subsidy concerns belong to the FSR notification and Commission-review process, while suspected collusion requires sufficiently plausible indications and verification that bids are autonomous.
Use separate legal routes, coordinated evidence gathering, tenderer participation, correct decision-making authority and a proportionate written outcome.
Sources
This article provides general legal information, not advice for a specific matter. Laws, facts and procedural deadlines may change the result. Follow the linked primary sources and obtain local advice before acting.