Abstract
The concept of Company in our mercantile legislation was conceived under the contractualist thesis, which requires the participation of two or more persons in its formation (art. 98 C. Co.). However, the issuance of Decree 4463 of 2006, which regulates Article 22 of Law 1014 of 2006, allowed the incorporation of sole proprietorships, creating a scenario of debate regarding their existence and legality; a rule that was sued before the Council of State, which, through a ruling of January 20, 2011, declared the nullity regarding the category of "sole proprietorships", ratifying plurality as an essential requirement of the partnership contract. Even so, the high court did not modulate the scope against the companies that were constituted while the norm was in force. The present initiative shows that the ex tunc effect of the annulled act resulted in the fact that it never existed and never produced effects, which puts in a legal limbo the single-member companies formed on the basis of that rule, vitiating even the subsequent actions. In order to measure the consequences of this scenario, in a geographical context, the number of affected societies was established in two cities of the Atlantic coast with a high index of commercial development, considering legal options that support the legalization of their existence; this study can be extended to other regions of the country.