Keywords: Big Data; Regulation; Lex Mercatoria; Privacy.
Big Data is the object of this legal discourse. The Author wonders whether and how this massive data collection disrupts the traditional legal categories and how to design new rea¬sonable paradigms for Big Data. In particular, the "lex mercatoria" and privacy in the relation¬ship with Big Data are taken into consideration. As for the "lex mercatoria", the types of antitrust offenses if they maintain their constituent elements - markets and abusive of power - be¬come empty skeletons because they will not be able to grasp the new dominances in the data drive markets. Instead, the Author proposes to make the "lex mercatoria" porous to the changes of the technique and inclusive of the "abuses 4.0" committed by the Web Giants. Privacy has also been strained by the eruption of the phenomenon under consideration, which has rendered the original protection based on informed consent unnecessary. On the contrary, the essay opens up to unprecedented methods of protection: the visibility of algorithms within the limits of intelligibility and their submission to a strict judicial review for the predictive analyzes harmful to citizens. The argumentative path ends with a proposal for regulation, suitable of protecting the rights against the technical risks, but also capable of following up the tension of classical constitutionalism towards the substantial equality.