Introduction
Contractor liability in Turkish public procurement contracts is one of the most important legal issues for companies performing public contracts in Turkey. Contractors, suppliers, service providers, construction companies, subcontractors, consultants and foreign companies may face serious liability if they fail to perform public procurement contracts in accordance with the tender documents, technical specifications, administrative specifications and the signed contract.
Public procurement contracts in Turkey are mainly governed by Public Procurement Contracts Law No. 4735. This law applies to contracts signed after tenders conducted under Public Procurement Law No. 4734. Law No. 4735 states that contracts cannot contain provisions contrary to tender documents, that contract provisions cannot be changed except in legally permitted cases, and that the parties have equal rights and obligations in the implementation of public procurement contracts.
Contractor liability may arise from many different situations: late delivery, defective goods, non-compliant services, faulty construction, use of fraudulent materials, breach of technical standards, failure to complete the work, unauthorized assignment, failure to comply with occupational health and safety obligations, damage to the administration, prohibited acts, false documents, force majeure disputes, failure to pay tax or social security debts, and post-acceptance defects.
For companies, the key point is clear: winning a public tender is not the end of legal risk. In many cases, the real liability begins after contract signing.
Legal Framework of Contractor Liability
The main source of contractor liability is Law No. 4735. Article 7 requires public procurement contracts to include mandatory provisions such as the contract price, payment terms, performance bond, warranty obligations, delivery and acceptance conditions, delay penalties, force majeure, inspection and acceptance procedures, termination conditions, personnel responsibilities, occupational health and safety obligations and dispute resolution clauses.
This means contractor liability must be analysed through a combination of statutory law and contract documents. The signed contract, administrative specification, technical specification, tender notice, standard forms, project documents, progress payment records, inspection reports and acceptance minutes may all become relevant.
Public procurement contracts are stricter than ordinary private contracts. A contractor usually cannot rely on informal negotiations, oral instructions or commercial flexibility unless they are properly documented and legally permitted. Under Law No. 4735, post-signing contract amendments are limited, and additional contracts cannot generally be executed except in cases allowed by law.
Main Types of Contractor Liability
Contractor liability in Turkish public procurement contracts can be grouped into several categories.
The first category is performance liability. The contractor must perform the goods, services or works exactly as required by the contract and tender documents.
The second category is delay liability. If the contractor fails to complete the work or deliver the goods or services on time, delay penalties may apply.
The third category is defective performance liability. The contractor may be liable for defective goods, faulty services, poor workmanship, non-compliant materials or technical defects.
The fourth category is financial liability. This includes performance bond forfeiture, additional performance bond obligations, compensation claims and deductions from progress payments.
The fifth category is administrative sanction liability. Serious breaches may lead to debarment from public tenders.
The sixth category is criminal liability. If the contractor’s conduct constitutes a criminal offence, criminal complaints may be filed.
The seventh category is post-acceptance liability, especially in construction works, where liability may continue for many years after final acceptance.
Liability for Performing the Contract in Accordance With Tender Documents
The contractor’s primary obligation is to perform the contract in accordance with the tender documents and the signed contract. This obligation covers quality, quantity, timing, technical standards, delivery method, personnel requirements, equipment, materials, reporting obligations and acceptance conditions.
Article 20 of Law No. 4735 provides that if the contractor fails to fulfil its commitment according to the tender documents and contract provisions, or fails to complete the work on time, and the same situation continues despite a written warning of at least ten days, the administration terminates the contract. In such a case, the performance bond and any additional performance bond are recorded as revenue, and the account is liquidated according to general rules.
This is one of the strongest forms of contractor liability. A contractor may lose the contract, lose its guarantees and face further compensation or debarment risk. Therefore, every contractor should treat written warnings from the administration as urgent legal documents.
Delay Liability and Delay Penalties
Delay is one of the most common liability grounds in public procurement contracts. The contract and tender documents usually specify the delivery period, work completion date, service period or project milestones. They also state delay penalties.
Article 7 of Law No. 4735 requires public procurement contracts to include penalties to be applied in case of delay. If the contractor fails to perform on time and cannot rely on an accepted time extension, force majeure or administrative delay, the administration may impose delay penalties.
Delay liability is particularly important in construction works, medical device supply, software implementation, maintenance services, catering, security, transportation and infrastructure contracts. In some cases, delay penalties may accumulate and make the contract financially unsustainable.
The contractor should not wait until penalties are deducted from progress payments. If the delay is caused by the administration, force majeure, late site delivery, project change, permit delay or another non-contractor reason, the contractor should immediately request a time extension in writing and preserve evidence.
Performance Bond Liability
Performance bonds are central to public procurement liability. The performance bond secures proper performance of the contract. If the contractor defaults, fails to perform, requests termination due to financial incapacity or engages in prohibited acts, the performance bond may be recorded as revenue.
Article 12 of Law No. 4735 also regulates additional performance bond. Where price difference is paid and this creates an increase in the contract amount, an additional performance bond equal to 6% of the increase is taken; this may also be deducted from progress payments.
Article 13 regulates return of performance bonds. The bond is returned only after the contractor performs according to the contract and tender documents, has no debt to the administration, and satisfies social security and acceptance-related conditions. In construction works, half of the bond may be returned after approval of the provisional acceptance minutes and correction of defects, while the remaining part is returned after final acceptance and social security clearance.
This means performance bond liability may continue even after physical completion. Contractors should manage acceptance, social security clearance, warranty obligations and debt issues carefully.
Liability for Tax, Social Security and Other Debts
Contractor liability is not limited to technical performance. Article 13 of Law No. 4735 provides that if the contractor’s debts to the administration or Social Security Institution, or legal tax deductions from wages and wage-like payments, are not paid by the final acceptance date in construction works or by the acceptance or warranty expiry date in other works, the performance bond may be converted into cash without protest or court judgment and set off against those debts.
This is a major risk in labour-intensive service contracts and construction works. Even if the contractor performs the main work, unpaid social security or tax-related liabilities may delay or prevent return of the performance bond.
Contractors should therefore maintain clean tax, payroll and social security records throughout the contract period. Waiting until final acceptance to resolve these issues may create serious cash-flow and guarantee problems.
Defective Goods, Services and Works
Defective performance is a major source of liability. In goods procurement, defects may include non-compliant products, missing certificates, wrong models, inadequate warranty, defective materials or failure to meet technical specifications. In service contracts, defects may include incomplete service, insufficient personnel, poor quality, failure to meet service levels, unsuitable materials or non-compliance with reporting obligations. In construction contracts, defects may include faulty workmanship, defective materials, non-compliance with project documents or violations of engineering rules.
Article 11 of Law No. 4735 provides that inspection and acceptance procedures for delivered goods, services, works or completed jobs are carried out by inspection and acceptance commissions established by the administration, consisting of at least three persons. Acceptance procedures cannot be conducted before the goods or work are delivered.
This means formal acceptance is legally important. A contractor should not rely only on informal statements that the work is “acceptable.” Written acceptance records, inspection minutes, test reports and delivery documents are essential.
Prohibited Acts During Contract Performance
Article 25 of Law No. 4735 lists prohibited acts during contract performance. These include interfering with contract-related procedures through fraud, promise, threat, influence, benefit, agreement, corruption or bribery; preparing or using false documents; using fraudulent materials, tools or methods; performing defective or faulty works contrary to technical rules; damaging the administration; using knowledge and experience against the administration; failing to perform the commitment outside force majeure; and assigning or taking over the contract contrary to Article 16.
These prohibited acts create severe liability. They may lead to contract termination, forfeiture of guarantees, debarment and criminal complaints. They also create reputational damage and may affect future tender participation.
Companies should implement compliance controls for every public contract. False certificates, manipulated test reports, unauthorized material changes, informal side agreements, bribery risks and defective workmanship must be prevented through internal audit, technical supervision and legal review.
Debarment Liability
Article 26 of Law No. 4735 provides that persons found to have committed prohibited acts listed in Article 25 may be prohibited from participating in public tenders for a period of not less than one year and up to two years, including tenders of all public institutions and organizations covered by the relevant scope. The debarment decision may also extend to partners of legal entities depending on the company type and ownership structure.
Debarment is one of the most serious consequences of contractor liability. It can prevent a company from participating in future public tenders and may affect group companies, majority shareholders or partners.
For foreign companies, debarment may destroy future Turkish public-sector opportunities. For Turkish companies, it may affect ongoing business strategy, bank relationships, reputation and eligibility for future projects.
Criminal Liability of Contractors
Article 27 of Law No. 4735 regulates criminal liability. It provides that even if discovered after completion and acceptance, where acts listed in Article 25 constitute offences under the Turkish Penal Code, a criminal complaint is filed with the competent public prosecutor against the relevant real or legal persons and their partners or representatives. In addition to criminal penalties, court-ordered debarment may apply after the administrative debarment period.
This provision is particularly important for cases involving forged documents, fraudulent materials, bribery, collusion, corruption, intentional defective works or conduct causing public damage.
Contractors should understand that public procurement liability may move from administrative law into criminal law. Internal compliance systems should therefore include anti-bribery controls, document authenticity checks, procurement ethics training and strict approval procedures for technical submissions.
Liability of Construction Contractors and Subcontractors
Construction contractors and subcontractors face special long-term liability. Article 30 of Law No. 4735 provides that in construction works, contractors and subcontractors are jointly liable for damages caused by failure to construct according to engineering and technical rules, use of fraudulent materials and similar reasons. This liability covers the entire structure from the start date until final acceptance and continues jointly for fifteen years from the approval date of final acceptance.
This is one of the strongest liability regimes under Law No. 4735. It means that construction liability does not end with provisional acceptance or even final acceptance. If defects later appear due to poor workmanship, fraudulent materials or non-compliance with technical rules, the contractor and subcontractors may remain liable for many years.
Construction contractors should maintain detailed project records, material certificates, test reports, site diaries, inspection minutes, photographs, subcontractor files and correspondence. These documents may become critical years later.
Supplier Liability
Article 33 of Law No. 4735 regulates supplier liability. Suppliers are directly responsible for damages arising from defective or non-standard materials being provided or used, failure to perform commitments according to the contract and specifications, and similar causes. The damage is completed and compensated by the supplier according to general provisions, and Article 27 may also apply where relevant.
This is important for goods procurement. A supplier cannot defend itself merely by stating that it delivered something. The goods must comply with the contract, technical specification, standards, warranty obligations and acceptance requirements.
Supplier liability may continue through warranty periods, after-sales service obligations, spare part commitments and defect correction duties. In medical devices, industrial equipment, vehicles, laboratory systems and software-related goods, technical compliance and documentation are especially important.
Service Provider Liability
Article 34 of Law No. 4735 regulates service provider liability. Service providers are directly responsible for damages caused by defective or non-standard material selection, provision or use, design errors, implementation errors, inspection deficiencies, failure to perform according to contract and specification provisions, and similar causes.
Service providers should pay particular attention to personnel, equipment, reporting, service continuity, materials, occupational health and safety, data security, quality control and documentation.
In cleaning, security, catering, maintenance, transportation, call centre, software support and facility management contracts, service provider liability may arise from daily operational failures. Therefore, contractors should create performance logs, personnel attendance records, monthly reports, service level reports, incident records and correspondence with the administration.
Consultant Liability
Article 32 of Law No. 4735 regulates consultant liability. In consultancy services, service providers are directly responsible for damages caused by design errors, implementation mistakes, inspection deficiencies, incorrect approximate cost determination, failure to perform works in accordance with applicable legislation, conduct contrary to professional ethics, failure to use knowledge and experience in the administration’s interest and similar reasons. If the consultancy service involves construction supervision, the consultant may be jointly liable with the construction contractor and subcontractors for fifteen years.
This is especially important in design, engineering, project management, supervision and technical consultancy contracts. A consultant’s mistake may cause major public losses, defective construction, wrong procurement decisions or project delays.
Consultants should maintain professional liability insurance where appropriate, document technical decisions and ensure that all design, supervision and reporting obligations are performed in writing.
Unauthorized Assignment Liability
Article 16 of Law No. 4735 states that a public procurement contract may be assigned only in compulsory cases and with written approval of the contracting officer. The assignee must satisfy the original tender conditions. Unauthorized assignment or violation of the three-year assignment restriction leads to termination, and Articles 20, 22 and 26 apply to the assignor and assignee.
This creates major liability in corporate restructurings, mergers, group-company transfers, subcontractor arrangements and foreign investor projects. Public contracts cannot be transferred like ordinary private contracts.
A contractor should obtain legal review before any transfer of contract, change of performing entity, restructuring or operational handover. Unauthorized assignment may lead to termination, forfeiture of guarantees and debarment.
Financial Incapacity and Contractor-Initiated Termination
Article 19 of Law No. 4735 regulates the contractor’s written notification that it cannot fulfil its commitment due to financial incapacity, except in force majeure cases. In such a situation, the performance bond and any additional performance bond are recorded as revenue, the contract is terminated without further protest and the account is liquidated according to general provisions.
This rule shows that financial difficulty is generally a contractor risk. Inflation, exchange-rate losses, financing problems or supplier price increases do not automatically excuse performance unless a specific price difference, temporary statutory mechanism or force majeure rule applies.
A contractor should not send a financial incapacity notice without understanding its consequences. It may trigger termination, loss of guarantees, compensation liability and debarment risk.
Damages Liability After Termination
Article 22 of Law No. 4735 provides that in terminations under Articles 19, 20 and 21, performance bonds and additional performance bonds are updated from the date they were received until the date they are recorded as revenue according to the monthly wholesale price index, and the difference is collected from the contractor. It also provides that forfeited guarantees cannot be set off against the contractor’s debt, and that damages suffered by the administration due to termination are compensated by the contractor.
This is a severe liability regime. The contractor may lose the bond, pay the updated difference, compensate administrative damages and face debarment.
Therefore, contractors should treat termination risk as a major financial exposure. A public procurement contract should not be priced only according to expected profit; the contractor should also calculate default, bond and damage risks.
Force Majeure as a Defence Against Liability
Force majeure may protect the contractor from liability where the statutory conditions are met. Article 10 of Law No. 4735 lists natural disasters, lawful strikes, general epidemics, partial or general mobilization and similar cases determined by the Public Procurement Authority as possible force majeure events. However, for the administration to accept the event as force majeure, it must not arise from the contractor’s fault, must prevent performance, must be beyond the contractor’s power to remove, must be notified in writing within twenty days and must be documented by competent authorities.
Force majeure is not automatic. Commercial hardship, increased costs or supplier inconvenience are not enough by themselves. The contractor must prove causation and inability to perform.
If force majeure is accepted and the contract is terminated due to force majeure, Article 23 provides that the account is liquidated according to general provisions and the performance bond and additional performance bond are returned.
Electronic Guarantees and Modern Liability Risks
Contractor liability also includes compliance with modern electronic guarantee mechanisms. The Public Procurement Authority announced that, from 5 January 2026, contract-stage guarantees such as additional performance, advance payment, final account and provisional acceptance deficiency guarantees could be submitted through Takasbank, with the administration identifying the contractor on EKAP and the contractor obtaining a reference number through EKAP before applying to the bank or insurance company.
The Authority also announced that for tenders under Law No. 4734 with announcement or invitation dates on or after 1 April 2026, contract-stage guarantee letters and surety bonds for additional performance, advance payment, final account and provisional acceptance deficiency guarantees will be issued electronically through EKAP-Takasbank integration.
This creates a new compliance layer. A contractor may face liability not only for physical performance but also for failure to provide required electronic guarantees at the correct stage of the contract.
Liability in Additional Works, Work Decrease and Liquidation
Article 24 of Law No. 4735 regulates additional works, work decrease and liquidation. In goods, services and construction contracts, additional works may be performed by the same contractor within legal limits if unforeseeable circumstances make the increase necessary, the additional work remains within the main project and separating it from the original work is technically or economically impossible without burdening the administration. The limit is generally 10% for turnkey lump-sum construction contracts and 20% for unit price goods, services and works contracts.
This provision also creates contractor liability. If the contractor refuses to perform lawful additional works within the statutory and contractual limits, or fails to complete the contract despite a lawful work decrease, disputes may arise.
At the same time, the contractor should not perform additional works based only on oral instructions. Written administrative approval and legal basis are essential.
Post-Acceptance Liability
Contractor liability may continue after acceptance. This is most obvious in construction works because Article 30 provides for fifteen-year joint liability from final acceptance approval for damages caused by non-compliance with engineering and technical rules, fraudulent materials and similar reasons.
But post-acceptance liability may also arise in goods and services where warranty, maintenance, after-sales support, spare parts, software updates or defect correction obligations are included in the contract.
Contractors should not close their project file immediately after acceptance. They should preserve records until all warranty, final account, guarantee return and limitation-related risks are resolved.
Practical Checklist for Contractors
A contractor performing a Turkish public procurement contract should follow a structured liability checklist.
First, review the signed contract and all tender documents. Second, identify delivery dates, performance milestones, technical standards, warranty obligations and delay penalties. Third, maintain written records of all performance steps. Fourth, preserve material certificates, test reports, service logs, site diaries, delivery notes and acceptance records. Fifth, respond immediately to administrative warnings. Sixth, request time extension in writing where delay is not attributable to the contractor. Seventh, notify force majeure within twenty days and document it through competent authorities. Eighth, avoid unauthorized assignment or informal subcontracting. Ninth, maintain tax and social security compliance. Tenth, monitor performance bond and additional performance bond obligations. Eleventh, document all defects and corrections. Twelfth, seek legal advice before termination, financial incapacity notification or contract transfer.
Common Mistakes by Contractors
The first common mistake is treating a public procurement contract like a private commercial contract. Public contracts are stricter and more formal.
The second mistake is relying on oral approvals from administration personnel.
The third mistake is ignoring written warnings.
The fourth mistake is failing to document performance.
The fifth mistake is assuming that financial difficulty excuses non-performance.
The sixth mistake is missing the twenty-day force majeure notice period.
The seventh mistake is using substitute materials without written approval.
The eighth mistake is assigning performance to another entity without legal permission.
The ninth mistake is failing to maintain tax and social security records.
The tenth mistake is closing the project file before guarantee and post-acceptance obligations end.
Legal Remedies in Contractor Liability Disputes
Contractor liability disputes may involve delay penalties, defective performance allegations, performance bond forfeiture, termination, debarment, damages claims, final account disputes, acceptance refusal or criminal complaints.
The correct remedy depends on the dispute. The contractor may need to submit written objections, request time extension, challenge progress payment deductions, file administrative or judicial proceedings, seek return of guarantees, contest debarment, or defend against damages claims.
A strong defence requires evidence. The contractor should preserve the contract, tender documents, correspondence, EKAP records, site reports, inspection minutes, acceptance documents, photographs, test results, payroll and social security records, invoices and technical reports.
Frequently Asked Questions
What law governs contractor liability in Turkish public procurement contracts?
Contractor liability is mainly governed by Public Procurement Contracts Law No. 4735, together with the signed contract, tender documents, administrative specification, technical specification and relevant secondary legislation.
Can the administration terminate the contract for non-performance?
Yes. If the contractor fails to perform according to the tender documents and contract or fails to complete on time, and the situation continues despite a written warning of at least ten days, the administration terminates the contract and records the guarantees as revenue.
What happens to the performance bond after contractor default?
In termination under Articles 19, 20 and 21, the performance bond and additional performance bond are recorded as revenue, updated according to the statutory index mechanism and the difference may be collected from the contractor.
Can defective construction create long-term liability?
Yes. In construction works, contractors and subcontractors are jointly liable for damages caused by non-compliance with engineering and technical rules, fraudulent materials and similar reasons, including a fifteen-year liability period after final acceptance approval.
Can suppliers and service providers be directly liable?
Yes. Suppliers are directly liable for damages caused by defective or non-standard materials and failure to perform according to the contract and specifications. Service providers are directly liable for damages caused by defective materials, design errors, implementation mistakes, inspection deficiencies and non-compliant performance.
Can prohibited acts lead to debarment?
Yes. Article 26 provides that persons who commit prohibited acts under Article 25 may be prohibited from participating in public tenders for at least one year and up to two years.
Can force majeure protect the contractor?
Yes, but only if the Article 10 conditions are satisfied: the event must not arise from contractor fault, must prevent performance, must be beyond the contractor’s ability to remove, must be notified in writing within twenty days and must be documented by competent authorities.
Conclusion
Contractor liability in Turkish public procurement contracts is broad, strict and multi-layered. It includes performance liability, delay liability, defective performance liability, financial liability, guarantee liability, administrative sanction risk, criminal liability and post-acceptance responsibility.
Law No. 4735 creates a detailed framework. Contractors must perform exactly according to the tender documents and contract. Failure may lead to delay penalties, termination, performance bond forfeiture, compensation claims and debarment. Prohibited acts may also trigger criminal complaints. In construction works, liability may continue for fifteen years after final acceptance approval.
For contractors, the safest strategy is disciplined contract management. Every instruction, delay, delivery, inspection, defect, correction, force majeure event and acceptance step should be documented in writing. Public procurement contracts are won with price and technical capacity, but they are safely completed with legal compliance, evidence and careful risk management.
For Turkish and foreign companies alike, contractor liability is not a secondary issue. It is one of the central legal risks of doing business with Turkish public authorities. A contractor that understands its obligations before signing and manages performance with proper documentation can reduce liability, protect its guarantees and preserve future public tender eligibility.
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