Contents
- What can be gap-filled, and what belongs to another instrument?
- What does gap-filling prohibit and what does it allow?
- As a contracting authority: what makes the notice defensible?
- As a tenderer: how should you respond to the notice you receive?
- Voluntary gap-filling: strategic instrument or trap?
- What may be changed during a gap-fill?
- What has changed in the past two years?
- Frequently asked questions about the gap-fill notice
Responding badly to a gap-fill notice has not meant the same thing since November 2024. The practice of the Public Procurement Arbitration Board (KDB) has narrowed the room for manoeuvre in two directions, and since 29 May 2025 Kbt. 71. § has carried a new subsection (9a) that steers invalidation onto a more proportionate track. This article works through what all of that means on the contracting-authority and the tenderer side for the next notice that lands through the EKR.
What can be gap-filled, and what belongs to another instrument?
Kbt. 71. § (1)-(11) holds three evaluation instruments together: gap-filling, a request for clarification, and correction of a calculation error. The most frequent boundary dispute is whether filling a given gap is still a document-level correction or already a substantive clarification. The table below sorts the practical dividing line along the characteristic case groups of the three instruments.
Ordering a gap-fill under Kbt. 71. § (1) is an obligation, not an option. The contracting authority cannot choose to walk past a curable gap and declare the tender invalid outright. The purpose of the instrument is that "a tenderer should not be put at a competitive disadvantage by administrative means". The technical framework for submission through the EKR is filled in by Sections 11 and 17 of Government Decree 424/2017. (XII. 19.). The same decree also governs the timing of the deadline and the opening.
| Instrument | What it covers | Typical example |
|---|---|---|
| Gap-filling | A missing document, declaration or certificate, or a formal defect in one | The specimen signature document was omitted, the company register extract is older than 60 days, the reference declaration does not state the period of performance |
| Request for clarification | Clarification of an ambiguous substantive element, with no document missing | A point in the technical description submitted can be read more than one way, and it is uncertain whether it meets the specification |
| Correction of a calculation error | An obvious arithmetical divergence, a summation or rounding error | The product of the unit prices and the quantities does not add up to the total price presented |
The doctrinal backdrop is provided by chapter VI of the Boros-Juhász-Lantos-Tátrai textbook "Közbeszerzés" (Public Procurement), but the third edition closed in 2019 and does not reflect the November 2024 and 2025 guidance amendments. The up-to-date layer comes from the guidance documents, the precedent material of Közbeszerzési Levelek (Public Procurement Letters), and recent KDB decisions.
What does gap-filling prohibit and what does it allow?
The elements of the absolute prohibition
The room for manoeuvre in gap-filling is bounded by an absolute prohibition under Kbt. 71. § (8). A gap-fill may only be directed at a non-significant, individual point of detail or a non-significant change to a tender element. It cannot touch the total tender price, the component prices subject to evaluation, or the ranking between tenderers. Under a lump-sum contract, internal rearrangement of the cost lines is permitted as an exception, provided the total price stays unchanged. The "limits of gap-filling" page of the Primer supplies the framework of principle for this: a gap-fill cannot break through the binding effect of the tender, cannot breach the equal treatment principle under Kbt. 2. §, and cannot touch the substantive content of the szakmai ajánlat, the part of the tender addressing the subject matter of the procurement and the contract conditions.
| Item | Prohibited or permitted |
|---|---|
| Changing the total tender price | Prohibited |
| Changing a component price subject to evaluation | Prohibited |
| Touching the ranking between tenderers | Prohibited |
| Internal cost-line rearrangement in a lump-sum contract with the total price unchanged | Permitted |
| Repeated gap-filling of the same gap | Prohibited (prohibition on double gap-filling) |
| A new gap-fill for a new gap not visible in the first round | Permitted |
| Supplying a specimen signature document, a company register extract or a reference declaration | Permitted |
| Changing the substantive content of the szakmai ajánlat (beyond the level of a point of detail) | Prohibited |
The prohibition on double gap-filling
The prohibition on double gap-filling is one of the most important narrowing elements in recent KDB practice. Decision D.455/2023 of the KDB records that where the permit submitted in response to a gap-fill notice was valid at the moment of submission but ceases to be in force before the gap-fill deadline expires, the contracting authority cannot launch a further notice on the same subject. The original submission becomes the basis of the evaluation under Kbt. 71. § (10). D.428/16/2021 adds that where certificates have been attached only in part, the gap-fill may be ordered solely for the missing items. The main rule, then, is this: a gap-fill may be directed at one gap only once, and a further round can only be launched where the first one brings up a new deficiency that was not visible in the first round.
What happens to a late gap-fill?
Under Kbt. 71. § (10), where the gap-fill is omitted or performed late, the evaluation continues on the basis of the original tender and invalidity does not set in automatically. The standard is not "it was not sent in, so the tenderer is out", but "it was not sent in, so the evaluation runs on the original content".
Is a "HUF 0" tender element valid?
One of the line items in the tender reads "HUF 0". At first glance this looks like a ground for invalidation under Kbt. 73. §, but validity depends on the contract construction it sits in. Under a lump-sum contract, the "HUF 0" is an internal rearrangement between items rather than a change in price, and it falls under the lump-sum exception in Kbt. 71. § (8). In a non-lump-sum construction the same thing is already a question of price content, and it can lead to invalidation.
The two relevant KDB decisions together supply the standard. D.811/15/2024 records that a tender element with a value of "0" calls for an explanation, and that if it is unexplained or several such items appear, gap-filling will not necessarily cure the defect. D.20/21/2021, by contrast, held for a lump-sum contract that a "HUF 0" cost line is not in itself unlawful and that the contracting authority must clarify the background through a gap-fill or a request for clarification before declaring the tender invalid.
The practical standard, then, is that on seeing a "HUF 0" item the contracting authority cannot invalidate at the first step. The evaluation runs in two stages: first the notice clarifying the background explanation, then the assessment of the answer. Within a lump-sum framework and with an evidenced background, the tender remains defensible.
In cases brought on the merits under Kbt. 73. §, the applicant wins in 51% of cases, the lowest success rate among the high-volume Kbt. sections. Every second challenge by an applicant against an invalidation succeeds before the KDB. If the contracting authority reads the gap-fill limits too narrowly and invalidates on that basis, it statistically faces close to even odds of a successful legal remedy against it.
As a contracting authority: what makes the notice defensible?
The substantive quality of the gap-fill notice either protects you directly or leaves you open to challenge in a remedy procedure. The minimum content of the notice comprises three elements: a specific identification of the document the gap relates to, a statement of how it is to be supplied, and direct service on the tenderer concerned with simultaneous notification of the other participants.
What is worth writing into the notice, even where it is not mandatory
The KDB laid down the clarity requirement more than a decade ago: the gap-fill notice must identify specifically, and in a way that cannot be read more than one way, which document or substantive element the gap relates to (D.81/12/2013). A vague notice is on its own a legal-remedy risk.
Kbt. 71. § (2) gives no substantive standard for an appropriate deadline. In practice it follows from the nature of the document to be supplied, the scope of the notice and the evaluation timetable taken together. A few working days is proportionate for supplying a specimen signature document, but not for a foreign official extract.
Kbt. 69. § (the scope of the participation conditions and the certificates) is the most frequently cited section in KDB decisions, appearing in 14.8% of cases decided on the merits. This is precisely what most gap-fill notices are directed at, and in remedy procedures launched under this section the applicant wins in 73.3% of cases decided on the merits. Statistically, an omitted gap-fill obligation leads to a KDB decision unfavourable to the contracting authority with close to three-in-four odds.
The elements of a good gap-fill notice
-
Specific identification of the document
The notice should name precisely which document, declaration or certificate the gap relates to. Wording at the level of "your tender is incomplete" fails the D.81/12/2013 standard.
-
Stating how it is to be supplied
A signed original, a dated new declaration, an official extract, a certified translation. The tenderer should not have to work it out.
-
Naming the statutory anchor
The notice should record which subsection of Kbt. 71. § and which section of Government Decree 424/2017. the gap-fill rests on. It protects you too in any later remedy procedure.
-
A proportionate deadline
Measured against the nature of the document. The routinely applied "5 working days" is fine for a specimen signature document, but not for a foreign official extract.
-
A short statement of reasons
Why the gap arose (for example, "the specimen signature document submitted is dated January 2024, and the 60-day validity window has expired"). The statement of reasons is part of documenting the procedure.
-
Rules of service
Through the EKR, in line with Government Decree 424/2017., addressed directly to the tenderer concerned, not as a generic message.
-
Simultaneous notification of the other participants
Part of the minimum content of the notice, not an optional formality.
For continuous professional support with evaluation control, Sugallat's advisory service for contracting authorities accompanies the procedure from the drafting of the notice through to the defensibility of the evaluation minutes before the KDB.
Typical errors and the inverse risk nobody teaches
- Vague specification
- It is not clear which document is a mandatory tender element and which is not. The tenderer does not even know precisely what has to be supplied, and can lose out even where the mistake was made in good faith (D.192/16/2019, missing specialist documentation).
- Unequal application
- A gap-fill permitted to one tenderer is refused to another on the same subject. This breaches the equal treatment principle under Kbt. 2. § and is a standalone ground for a legal remedy (D.225/15/2019, the entire substantive part missing).
- Blocking a substantive correction
- The contracting authority refuses clarification of content where it would be acceptable within the framework of Kbt. 71. §. Decision D.325/12/2019 penalised exactly this loss of proportionality in a case about changing the warranty period from 48 to 36 months.
- Unlawfully penalising system-side upload errors
- An error originating in the EKR system rather than in the tenderer's intent cannot be a ground for invalidation where it can be cured within the framework of gap-filling (D.98/16/2019, a document uploaded to the wrong stage in a two-stage procedure).
The fifth practical risk is inverse in nature: the "gap-fill that was never ordered" is itself a ground for a legal remedy. If you walk past a curable gap and declare the tender invalid outright, the omitted notice is a breach of the obligation under Kbt. 71. § (1). The practical consequence is that where curability is arguable, order the notice and assess the conduct at the point of performance rather than invalidating outright. The defensible position is "I ordered it and it was not complied with", not "I never ordered it at all". If your evaluation control needs practical professional support, Sugallat's public procurement service for contracting authorities works at exactly this intersection.
As a tenderer: how should you respond to the notice you receive?
The gap-fill notice arrives. What do you do now? In practice the notice sets a short deadline of a few working days, and the tried and tested advisory reflex is to talk it through by phone rather than by email. You have to keep two layers in view at once: the substantive requirement of the notice and the original procurement documents. If you read the notice on its own you lose the connection, and with it the opportunity.
A black-and-white game, with no second chance
The outcome of a gap-fill is black and white. If the tender does not comply even with the gap-fill, it will be invalid. No second notice can be issued for the same gap (see the "The prohibition on double gap-filling" section). Where performance is late or omitted under Kbt. 71. § (10), the original tender becomes the basis of the evaluation. So the quality of the answer and the interpretation that precedes it decide the matter together. A gap-fill is not an iterative discussion with the contracting authority: one gap, one answer. Anyone uncertain about the substantive reading of the notice consults an expert before answering, not afterwards.
The steps of a successful gap-fill
After the notice arrives, the first half hour is worth more than the following two days: this is where it is decided whether the answer stays within the context of the original tender or slips into the prohibited scope under Kbt. 71. § (8). Failure in practice usually turns not on the content of the answer but on the sequence. Anyone who starts drafting the answer straight away, before retrieving the original documents, is likely to depart from what was undertaken earlier, and the gap-fill then runs into the prohibition in Kbt. 71. § (8). The sequence is not a matter of style but a matter of validity: the correct first step is re-reading the original tender, not drafting the answer.
-
Reading through the notice
What the contracting authority is asking for, which statutory anchor it relies on, what the deadline is and how submission is to be made. Where the notice is vague, the D.81/12/2013 standard makes it worth putting a written query back to the contracting authority.
-
Retrieving the original documents
A gap-fill is to be read in the context of the tender submitted, not on its own. The earlier undertaking is a mandatory starting point, and the answer cannot depart from it.
-
Deadline analysis
Whether the deadline in the notice means actual working days, and whether foreign official processing fits inside it. If not, request an extension on the basis of the proportionality requirement in Kbt. 71. § (2). For counting the working days themselves, the current working-day calendar is the reference, including the rearranged Saturdays and rest days.
-
Mode of submission
Under Section 11 of Government Decree 424/2017., through the EKR, on the channel the notice identifies. An external email is no substitute.
To assess a specific gap-fill situation, our tenderer advisory service reviews the reading of the notice, the sequence of the answer and the form of submission together.
Received a gap-fill notice? Or do you need to issue one?
In a specific situation, the steps under Kbt. Section 71 and the arbitration-board practice are rarely obvious. Let us review the notice or the response sequence with you so the right step lands in EKR within the deadline.
Voluntary gap-filling: strategic instrument or trap?
Voluntary gap-filling is set out in Kbt. 71. § (5): while a gap-fill deadline is open for any other participant, the tenderer may, without a separate notice, cure deficiencies the contracting authority has not called upon it to address. On paper it is a flexible instrument, in practice it is narrowed from several directions.
The first limit: a gap-fill notice missed earlier cannot be made good by the voluntary route. The scope of the instrument is narrow, because Kbt. 71. § (8), discussed under the absolute prohibition, applies in full force to voluntary gap-filling as well. So the instrument can only be used to correct a non-significant, individual point of detail. A voluntary change affecting a product definition or a technical parameter typically goes beyond the limits of voluntary gap-filling.
Why does the contracting authority have to exercise heightened diligence?
The 29 May 2025 amendment of the KH guidance introduced the contracting authority's "heightened diligence" as a new requirement when assessing a voluntary gap-fill. It must be documented where the voluntary change would substantively alter the tender or would breach the principles in Kbt. 2. §, and the assessment must follow the gap-fill limits strictly. The requirement carries a documentation burden and forms part of the evaluation minutes.
| Situation | Assessment |
|---|---|
| Curing a formal defect (an error in the date of issue, a defect in the form of signature) while another tenderer's deadline is open | Can be worth it, if the defect falls within the limits of Kbt. 71. § (8) (a point of detail, with no effect on the ranking) |
| Making good a missed gap-fill notice after the event | A trap: it cannot be used for this. Under Kbt. 71. § (10) the original tender becomes the basis of the evaluation |
| A substantive change to the content of the tender (a technical parameter, the performance period undertaken) | A trap: it goes beyond the limits of Kbt. 71. § (8), and the contracting authority has to reject it |
| Changing a component price subject to evaluation or the total tender price | A trap: an absolute prohibition, whether the gap-fill is voluntary or made in response to a notice |
| A change affecting the ranking (the tenderer would overtake the competitor ahead of it) | A trap: the ranking prohibition in Kbt. 71. § (8) applies to voluntary gap-filling as well |
When is a voluntary gap-fill advisable, and when is it a trap?
Voluntary gap-filling is a narrow instrument, sized for formal points of detail. Anyone trying to push a substantive change to the tender through it takes on a double risk: the contracting authority rejects it on the basis of heightened diligence, and conduct breaching the principles in Kbt. 2. § is a standalone ground for a legal remedy. The trap usually springs not at submission but at assessment: you also lose the opportunity for the formal correction, because the version containing the voluntary change is already on the record.
What may be changed during a gap-fill?
The participant-side dimension of gap-filling runs on three subsections of Kbt. 71. §: subsection (4) governs bringing in a new capacity-providing entity or subcontractor, subsection (6) governs the limits on a further gap-fill round, and subsection (9) governs replacement of the specialist presented for evaluation. Read together, the three build strongly on one another, and since November 2024 a separate exception has been wedged in for construction procurements.
Under Kbt. 71. § (4), a new capacity-providing entity or subcontractor may only be brought in where the entity originally named falls under an exclusion ground under Kbt. 62. § (1), or under 63. § where that section has been referenced, and subsection (6) may set a separate limit on a further gap-fill round. For the related exclusion-ground background, Sugallat's article on exclusion grounds and self-cleaning provides detailed guidance.
| Subsection | What it governs | Key condition |
|---|---|---|
| Kbt. 71. § (4) | Bringing in a new capacity-providing entity or subcontractor | The entity originally named falls under an exclusion ground under Kbt. 62. § (1) or 63. § |
| Kbt. 71. § (6) | Limits on ordering a further gap-fill round | It may only be directed at a new gap that was not visible in the first round. In a state construction investment the restriction cannot be applied from 22 November 2024 |
| Kbt. 71. § (9) | Replacement of the specialist presented for evaluation | The original specialist falls under an exclusion ground under Kbt. 62. § (1), or the replacement is necessary to satisfy the suitability criteria |
Why does construction get a separate exception?
Construction is the sector with the highest applicant success rate in cases closing with a decision on the merits: 84.6% (165/195), 11.3 percentage points above the 73.3% average. That sectoral risk profile sits behind the exception, which makes bringing in a new economic operator possible on a wider basis.
When does the Kbt. allow a specialist to be replaced?
Replacement of a specialist is a tightly drawn instrument under Kbt. 71. § (9). Within a gap-fill, the specialist may only be replaced where the original falls under an exclusion ground under Kbt. 62. § (1), or where the replacement is necessary to satisfy the suitability criteria. The substitute specialist must be at least equivalent in every relevant dimension, and a higher qualification cannot raise the evaluation score.
What has changed in the past two years?
The rules on gap-filling have picked up three amendment milestones since November 2024. Explanations predating November 2024 still surface among Google results, and on some points they no longer reflect the practice in force. The chronology below picks out only the points that bear on gap-filling.
| Date | Amending guidance | What it affects | Practical effect |
|---|---|---|---|
| 22 November 2024 | Amendment of two guidance documents | The restriction under Kbt. 71. § (6) cannot be applied in public procurements falling within the scope of Act LXIX of 2023 | In construction procurements, bringing in a new economic operator is possible on a wider basis |
| 29 May 2025 | Amendment of the gap-fill guidance (part of the 2 June package of five guidance documents) | New Kbt. 71. § (9a) subsection: undertakings that still qualify for the highest score at the substantiable threshold remain valid. Heightened diligence for assessing a voluntary gap-fill | A documentation burden for the contracting authority in assessing a voluntary gap-fill, a narrower scope for invalidation for the tenderer |
| 7 October 2025 | Subcontractor guidance (AV = alvállalkozó, subcontractor) | Clarification of the procedural framework for subcontractor notification, the content of declarations, and performance checks | Feeds back into gap-filling through the evaluation chain |
What does the new subsection (9a) bring to invalidation?
Of the three amendments, the most important new provision for the tenderer is Kbt. 71. § (9a). According to the guidance of 29 May 2025: where the tenderer made a larger undertaking on the bid-opening sheet than it can substantiate with its documents, but the substantiated value still reaches the threshold for the highest score available on the given award criterion, the tender remains valid. The score is based on the substantiated value, not on the overstated undertaking.
The provision loosens the earlier, rigidly invalidating practice where the overstatement confers no actual competitive advantage over other tenderers. It produces a more proportionate evaluation outcome, but it does not save a divergence between the bid-opening sheet and the underlying document where the substantiated value falls below the threshold.
Five KDB decisions on gap-filling
Alongside the guidance amendments, the layer of recent KDB decisions is the other point of reference. The five decisions cited at various points in this article, gathered here in one place:
- D.428/16/2021: the legal fiction attaching to certificates the tenderer itself attached to the tender, and the narrowing of the scope of a gap-fill where the attachment was partial (in detail in the "The prohibition on double gap-filling" section).
- D.455/2023: confirmation of the prohibition on double gap-filling (see the "The prohibition on double gap-filling" section).
- D.811/15/2024: a more recent decision tightening the framework for invalidating "zero forint" offers in the light of Kbt. 71. § (8) (see the "HUF 0" case).
- D.20/21/2021: the duty to clarify a "HUF 0" cost line before invalidation in the case of lump-sum contracts (see the "HUF 0" case).
- D.81/12/2013: the clarity standard for the gap-fill notice, governing for more than a decade and still governing after the recent guidance amendments (details in the section on the minimum content of the notice).
How does the subcontractor guidance feed back into gap-filling?
The subcontractor guidance adopted on 7 October 2025 is not directly about gap-filling, but it feeds back into it through the evaluation chain. It clarifies the procedural framework for subcontractor notification, the content of declarations, and performance checks, and in doing so it also clarifies the application of Kbt. 71. § (4) and (6) when a new economic operator is brought in. The practical consequence is that when gap-filling subcontractor documentation, the evaluation committee has to read the subcontractor guidance together with the gap-fill guidance.
What is worth taking into 2026?
Over the eleven months between November 2024 and October 2025, the legal instrument of gap-filling received a two-way fine-tuning: it narrowed where a loss of proportionality had to be penalised, and it widened where invalidation proved excessive. At the meta level, then, this is neither a tightening nor a loosening but a finer calibration of the proportionality standard.
Anyone working from pre-2024 routine is going wrong in two directions today. On the contracting-authority side, a vague notice and an omitted gap-fill are both legal-remedy risks. On the tenderer side, the first half hour after the notice decides whether the tender will be valid or invalid. The KDB reads the recent guidance documents and the underlying decisions together, and the evaluation committee has to do the same.
Frequently asked questions about the gap-fill notice
- Can gap-filling be applied where the certificate was not submitted at all?
- No. The law draws a sharp line between incomplete submission (curable) and complete absence (not curable). If the tenderer does not submit the certificate under Kbt. 69. § (4) at all, that is a complete absence, which leads to automatic invalidity. An error and a gap can be cured, a complete absence cannot: this simple three-step distinction sets the scope of Kbt. 71. § (8).
- How many times can the same gap be gap-filled?
- Once. D.455/2023 records that a gap-fill may be directed at a given gap only once, and that a further round can only be launched where the first gap-fill brings up a new deficiency that was not visible in the first round. Details in the "The prohibition on double gap-filling" section.
- Until when can a voluntary gap-fill be made?
- While a gap-fill deadline or a clarification deadline is open for any other participant (Kbt. 71. § (5)). If no such deadline is open for any other tenderer, no voluntary gap-fill can be launched, and it cannot be used after the event to make good a missed gap-fill response either. More in the section on voluntary gap-filling.
- Can a specialist be replaced through a gap-fill?
- Only within a narrow scope. Under Kbt. 71. § (9), replacing a specialist is possible where the original specialist falls under an exclusion ground under Kbt. 62. § (1), or where the replacement is necessary to satisfy the suitability criteria. It cannot be used to rescue an unsubstantiated evaluation undertaking after the event. Details in the sub-section on replacing a specialist.
- When is a tender invalid after a gap-fill?
- Where the tender does not meet the requirements even with the gap-fill. Where performance is omitted under Kbt. 71. § (10), however, there is no automatic invalidity and the evaluation continues on the basis of the original tender. Subsection (9a) brings relief: where the substantiated value of the undertaking reaches the threshold for the highest score available on the given award criterion, the tender remains valid. Worked through in the sub-section on subsection (9a).