The present title is based on the study of the fiduciary alienation contracts in guarantee of movable assets and application of the theory of substantial performance, since the judgment of REsp 1,622,555 in 2017, remained because it caused legal instability in the banking law, since it declared such theory inadmissible in the contractual specimen discussed here. The objective is to verify the applicability of the institute of the substantial amendment to this type of contract, analyzing the principle guiding contribution of such applicability, as well as to ascertain whether the judgment is in line with the general principles implicit in the legal system and the external circumstances of influencing the judgment, by means of the economic analysis of the law, legal hermeneutics, in addition to the procedural analysis on the repetitive demands, identifying the theoretical and practical elements essential to the matter and their application in Brazilian law. With a critical contribution, it will be analyzed the importance given to the consumer in the referred judgment, the compatibility of the rule of procedural law and material law.