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government contracting · 5 min read

5 mistakes that can void your government contract

ref. zam-2026-003by Roland De Jesús Larios Sanjuán · Associate Attorneyapril · 2026

Contracting with the State opens opportunities, but it also exposes contractors and public entities to a strict regime. An oversight at any stage — from the bidding terms to the final settlement — can translate into the contract being voided, non-payment for work performed, or fiscal, disciplinary and even criminal liability. These are five frequent mistakes and how to prevent them.

1. Contracting under a disqualification or conflict of interest

Disqualifications and incompatibilities (inhabilidades e incompatibilidades) exist to protect the transparency of public procurement. Signing a contract while subject to one — or having one arise during execution — can void it and compromise everyone involved. Before bidding or awarding, always verify the status of the bidder and its representatives.

2. Poorly accrediting the qualifying requirements

Experience, legal capacity and financial capacity must be demonstrated exactly as the bidding terms require. Incomplete documents, certifications that do not support what is claimed, or miscalculated financial ratios are a common cause of bid rejection and, later, of disputes. Documentary precision is not a formality: it is the foundation of a solid proposal.

3. Additions and modifications without legal support

Government contracts can be modified, but not in any manner and not without limit. Additions are subject to legal caps, and every modification must be duly justified and supported. Adding beyond what is allowed, or without technical grounds, opens the door to nullity and to findings by oversight bodies.

4. Skipping planning and objective selection

The planning principle and the duty of objective selection are the backbone of the system. Deficient preliminary studies, tailored bidding terms or evaluation criteria that favor one bidder are hotbeds of litigation and investigations. A well-structured process from the start protects both the entity and the serious contractor.

5. Executing without supervision or records

The execution stage requires supervision or independent oversight (interventoría) and orderly documentary support: minutes, reports, evidence of performance. Their absence complicates the settlement, facilitates objections and leaves the contractor without evidence to defend the work performed against challenges or claims.

How to avoid them

The common denominator of these mistakes is the lack of timely legal counsel. Advice should not arrive when there is already a problem, but from the pre-contractual stage: checking disqualifications, structuring the bid, validating modifications and keeping execution in order. Preventing costs far less than litigating a nullity or answering to an oversight body.

This article is general information and does not constitute legal advice for any specific case. Every situation is different. This is an English translation of the Spanish original, provided for convenience.

Roland De Jesús Larios Sanjuán
Roland De Jesús Larios Sanjuán
associate attorney · zam abogados
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