When must a contracting authority clarify or permit correction of a tender?

Short answer

EU law normally permits, but does not generally require, a contracting authority to ask for incomplete, erroneous or apparently missing information to be submitted, supplemented, clarified or completed. Article 56(3) of Directive 2014/24 makes that power subject to equal treatment, transparency and any contrary national rule.

The authority may clarify genuine ambiguity, correct an obvious material error, or sometimes obtain a document whose content objectively existed before the deadline. It cannot let a bidder improve price or technical substance, replace a failed item, add experience or third-party capacity acquired after the deadline, or supply a document expressly required on pain of exclusion.

An express duty to seek explanations arises where a tender appears abnormally low. If the supposed defect instead rests on an unclear, undisclosed requirement, the authority cannot simply exclude the bidder on that hidden basis; regularisation may be permissible, but EU law does not thereby create a universal duty to clarify. The result depends on the procurement documents, nature of the defect, national law and whether the correction would amount to a new tender.

Article 56(3) creates a controlled power

Where information or documentation submitted by an economic operator is or appears incomplete or erroneous, or specific documents are missing, Article 56(3) permits the authority to request submission, supplementation, clarification or completion within an appropriate period. National implementation may restrict or structure that power.

The provision does not authorise free negotiation after the deadline. It operates inside the core duties of equal treatment and transparency in Article 18. The authority should ask:

1. Was the disputed content fixed before the submission deadline?
2. Is the defect objectively identifiable as ambiguity, omission or material error?
3. Would the response merely evidence or explain the original tender?
4. Could it change price, ranking, technical solution or relied-on capacity?
5. Did the procurement documents expressly make the item mandatory on pain of exclusion?
6. Are all bidders in the same position treated equivalently?

The label “clarification” does not control. The economic effect of the bidder's response does.

Clarification cannot become a new tender

In SAG ELV Slovensko, the Court accepted limited clarification and correction of obvious material errors, but not an amendment that in reality produces a new tender.

“The correction or amplification of details of a tender” is possible “on an exceptional basis”, provided the amendment does not “lead to the submission of a new tender”. — SAG ELV Slovensko, C-599/10, paragraph 40

The authority should first examine all tenders, address all unclear sections of the affected tender, and send equivalent requests to bidders in the same situation unless an objectively verifiable reason justifies different treatment. A request designed after seeing the ranking to rescue the preferred bidder is incompatible with equal treatment.

Usually permissible examples include explaining an internal cross-reference, confirming which already-submitted figure controls where the answer is objectively apparent, or correcting an obvious transcription or arithmetic error without changing the intended offer.

Usually impermissible examples include choosing a different product after testing failure, replacing the technical method, changing the bid price or delivery promise, or supplying a new undertaking that creates eligibility only after the deadline.

Missing pre-existing evidence may sometimes be completed

Manova concerned a published balance sheet omitted from an application. The Court allowed the authority to request it because its contents objectively pre-dated the application deadline and the procurement documents had not said omission required rejection.

The document must “be objectively shown to pre-date that deadline”, and the contract documents must not have required it “on pain of exclusion”. — Manova, C-336/12, paragraphs 39–40

That distinction is practical. Asking for a copy of an existing certificate can evidence a situation already fixed. Allowing a bidder to obtain a qualification, commitment or capacity after the deadline changes the competitive facts.

Authorities should retain proof of the document's date and unchanged content. A later-created document raises a different and more difficult question: the authority must distinguish evidence of a fact fixed before the deadline from an instrument that creates capacity or changes the bid after the deadline.

Express exclusion clauses sharply limit correction

Where clear procurement documents require a declaration or document by the deadline and state that omission leads to exclusion, the authority generally must apply its own rule. In Archus and Gama, the Court held that an authority could not invite submission of declarations or documents required by the specifications but omitted before the deadline.

Equal treatment precludes inviting a bidder to submit documents “whose communication was required by the tender specification” but “which have not been submitted within the time limit”. — Archus and Gama, C-131/16, operative point 1

The same judgment preserved correction of an obvious clerical error or true clarification, provided bidders in the same situation are treated equally and the result is not a new tender.

National law can sometimes mandate regularisation. But the authority cannot invent a waiver after bids are opened where its published terms promised exclusion. Tenderers priced and prepared their offers in reliance on those terms.

An undisclosed or ambiguous requirement cannot fairly cause exclusion

The opposite problem arises when the alleged requirement was not clear in the procurement documents or applicable national law. In Pizzo, a bidder was excluded for not paying a fee whose application emerged only from administrative and judicial interpretation.

The Court held that transparency and equal treatment precluded exclusion for an obligation not expressly arising from the procurement documents or national law. Allowing the bidder time to regularise was compatible with equality and proportionality.

A contracting authority must “comply strictly with the criteria which it has itself established”. — Pizzo, C-27/15, paragraph 42

Where the authority drafted an ambiguous condition, it cannot choose a hidden interpretation after submission and exclude a bidder for failing to anticipate it. Depending on the defect, a lawful response may be regularisation, consistent application of the published terms, or cancellation and retendering. Pizzo does not establish that clarification is always mandatory.

New capacity or experience is substantive, not clerical

An operator cannot use clarification to reconstruct qualification. In Esaprojekt, documents introduced after the deadline included a contract performed by another entity and that entity's new commitment to provide capacity. The Court treated this as impermissible because it was absent from the initial bid.

The new material was “a substantive and significant amendment of the initial bid”, which was “more akin to the submission of a new tender”. — Esaprojekt, C-387/14, paragraph 42

There is an important difference between proving capacity already relied on and substituting a new source of capacity. Current Directive 2014/24 contains specific rules on replacing entities subject to exclusion or failing selection criteria; those provisions should not be confused with unrestricted tender correction.

Must the authority ask?

For ordinary ambiguity, EU law generally leaves discretion under Article 56(3), exercised consistently and under national law. The Court in SAG ELV Slovensko expressly did not derive a universal duty to clarify every non-compliant tender.

A duty arises where another provision or applicable national law requires dialogue. Article 69 expressly requires the authority to seek explanations where a tender appears abnormally low. Beyond that express case:

• national legislation may make completion mandatory within the limits of EU equal-treatment rules;
• once an authority uses clarification, equivalent requests must go to bidders in the same situation unless an objectively verifiable reason justifies different treatment; and
• an undisclosed obligation cannot support exclusion, although Pizzo says regularisation is permissible rather than invariably required.

Even then, the authority cannot request a substantive rewrite. If no lawful clarification can cure the defect, rejection may be required.

A defensible clarification process

• Freeze and preserve the tender as submitted.
• Identify the exact document clause and national rule.
• Record whether content existed before the deadline.
• Explain why the response cannot alter price, substance, ranking or capacity.
• Review all tenders before selecting recipients of requests.
• Use the same deadline and question for bidders in the same position.
• Ask neutrally; do not suggest a winning answer.
• Address every material ambiguity included in the request.
• Keep the request, response and evaluation rationale in the file.
• Give review bodies enough reasoning to test equality and transparency.

Conclusion

EU procurement law allows correction to preserve genuine competition, not to give a bidder a second attempt. Pre-existing evidence, obvious clerical mistakes and limited explanations can often be addressed. Missing mandatory documents, new qualifications, replacement solutions and material commercial changes ordinarily cannot.

The dividing line is whether the authority is discovering what the bidder actually submitted by the deadline or permitting it to submit something competitively different afterwards. Clear tender documents, equivalent treatment and a contemporaneous correction record are decisive.

Sources

• Directive 2014/24/EU, consolidated version of 1 January 2026, Articles 18, 56, 63 and 69
• Court of Justice judgment in SAG ELV Slovensko, C-599/10
• Court of Justice judgment in Manova, C-336/12
• Court of Justice judgment in Pizzo, C-27/15
• Court of Justice judgment in Esaprojekt, C-387/14
• Court of Justice judgment in Archus and Gama, C-131/16