The core of a fiduciary institution is trust, which led fiduciaries to be initially conceived as a trustee substitution and later on it identified as a guarantee in which the performance of the entrusted function must be diligent and concentrated on the achievement of the purpose proposed by a fiducial business. This figure has been extensively developed in the legal system, especially in the Colombian legal system, which has made the personal and real elements that are found in itself to lay the foundation of the principles that must be observed in the structuring, execution and settlement of fiduciary businesses, since those were developed by a [financial] section of the banking establishment until they were developed by specialized companies, as is currently the case. Regarding the administration of public fiduciary businesses, it is observed that these are present whenever the public resources managed are contributed directly or indirectly by state entities or third parties or contractors of the state, and this makes it valid to ask whether fiduciary institutions could be classified as fiscal managers and be held liable for the failure to comply with their legal and non-delegable duty of diligence. This aspect is analyzed and developed in the research presented here, and it can be seen that fiduciary companies are liable for financial liability for gross negligence, under a parameter of liability appropriate to a good business person and not to a good head of a family as stated in Article 1243 of the Code of Commerce, and therefore does not comply with the aforementioned legal provision.