Guarantees: the money that answers for the contract
The LCSP (Ley 9/2017, Spain's public procurement act) structures guarantees around three figures:
| Guarantee | Amount | When required |
|---|---|---|
| Garantía provisional (bid guarantee) | Up to 3% of the base budget (excluding VAT) | Exceptional: only where the tender documents justify it |
| Garantía definitiva (performance guarantee) | 5% of the final offered price (excluding VAT) | General rule, before award |
| Garantía complementaria (additional guarantee) | Up to a further 5% | Special cases, typically bids initially flagged as abnormally low |
The bid guarantee secures the seriousness of the offer: it answers for the bidder maintaining its proposal until award. It is exceptional today; most tender documents do not require it. The performance guarantee is the heart of the system: 5 per cent of the offered price, answering for penalties, damages for breach and defects during the warranty period. It can be lodged in cash, through a bank guarantee or a surety insurance policy, and in works contracts the documents may allow retention from the price. A bid with an aggressive discount initially caught by the abnormality presumption can trigger an additional guarantee of up to another 5 per cent, raising the total to 10 per cent: a financing cost worth factoring into the discount decision. Lodging, bank guarantees and release are detailed in the article on bid and performance guarantees.
Release closes the cycle: the performance guarantee is cancelled once the warranty period has expired and the final account is approved, provided no liabilities remain outstanding. For a contractor running several public works at once, the stock of live bank guarantees is a credit line that consumes financing capacity; claiming release as soon as the conditions are met, rather than waiting for the administration to act of its own motion, is treasury management as real as collecting a progress certificate.
The special review: challenging without going to court
Against the most significant decisions of a tender, the LCSP offers a fast, free challenge route prior to the courts: the recurso especial en materia de contratación (special procurement review), decided by independent administrative tribunals (the TACRC at state level and its regional equivalents). Its scope and deadlines are defined and worth knowing before they are needed.
Its scope is fixed by law: for works, contracts with an estimated value above 3,000,000 euros. Challengeable acts include the notices, the tender documents, exclusion decisions and, above all, the award. The deadline is fifteen working days, and a review lodged against the award automatically suspends contract signature, which gives the remedy real teeth: the administration cannot consummate the award while the tribunal decides.
For an excluded or second-ranked bidder, the special review is often the only practical chance of reversing a badly decided tender. Its requirements, deadlines and strategy are developed in the article on the special procurement review.
Transparency: everything is published
The LCSP made publicity the general rule with no value-based exceptions. The perfil de contratante (contracting authority's profile), hosted on Spain's public procurement platform or the regional equivalents, publishes the tender notices, the complete tender documents, the composition of the evaluation committees, the scoring minutes, the awards with their reasoning, the signatures and the modifications.
For bidders, that transparency has two practical uses. Before bidding, it allows the contracting authority's track record to be studied: what discounts have won similar tenders, how it scores technical submissions, how often it modifies its contracts. After the tender, it allows the evaluation to be scrutinised: the published minutes and technical reports are the raw material of any challenge. The only boundary is the confidentiality of bids: technical or commercial secrets designated by each bidder remain outside access, though the designation must be selective and justified, not blanket.
A system that rewards the informed bidder
Guarantees, remedies and transparency carry a single message: public works is a formalistic market where rights exist but do not enforce themselves. The bidder who prices the financing cost of its guarantees before setting the discount, reviews the published minutes after every lost tender and knows the special review deadlines turns regulation into competitive advantage.
Note: the amounts, time limits and legal references cited reflect Spanish legislation in force in 2026 (Ley 9/2017). Always check the tender documents and the rules applicable to each specific procedure.