This work relates to private autonomy in business contracts. The thesis is developed in two parts. The first part deals with the category of business contracts. It considers the special law of business contracts and analyses the characterizations of enterprise bargaining; it concludes by considering the business contracts as an autonomous category. The second part deals with relations between private autonomy and market regulation. It looks at private autonomy from a historical perspective and analyzes the various private autonomy limits introduced by the recent rules governing corporate contracts. The work concludes with the configuration of a new trend and with the analysis of the impact this may have in the traditional theory of contract and autonomy negotiations.