The dynamics of economical relations in this contemporaneous world, imposes, in turn, new needs for national juridical ordinances. Thus, granting the businesses with seriousness, security, transparency, and firmness has forced the adoption of some measures oriented towards regulating the level of juridical responsibility which the parties acquire when they are in the middle of conversations or agreements previous to the celebration of a contract. In effect, we pretend to determine, -with basis in the current regulation stipulated in Article 863 of the Commerce Statute-, the compensating and indemnifying obligation incurred by a pre-contractor in the event that, unilaterally and unjustifiably, he margins himself from the pre-contracting scenario, definitely frustrating the expectation towards the affirming of the contract. This censorable conduct of unilateral margining, certainly unrecognizing the medullar principle of good faith, fortunately, is heading the contractual constituency in Colombia.