The diversity of legal forms of companies and their legal nature determines the different approach of a legislator to the regulation of rights of those company members. Nevertheless, the dominant determination related to organization of the form of partnerships (general partnership and limited partnership) is dispositive nature of the regulation, which enables those company members to deviate from these rules in the organization of company rights in the constitutive acts, of their own free will, and to adapt them to their interests (deviation from the proportionality principle of share in the company right). The same applies to a good extent to a limited liability company, although it is of mixed legal nature of both partnership and corporation. On the other hand, the regulation of joint stock companies (especially open – public and mostly of those closed – non-public) is mostly mandatory, reducing party autonomy in regulating the rights of shareholders to the maximum possible extent down to the level of exception. This paper discusses the issue of possible limits to party autonomy of members of partnerships, as well as members of limited liability companies, in regulating some management, property, and special rights, such as the clauses created by the so-called good business practice (leonine clauses). In addition to that, considering that constitutive acts of companies and limited liability companies are also of contractual nature (which is exclusive at the moment of establishment), along with dispositive legal basis, the consideration is taken related to the question of the application of some general institutes of the contract law in the field of limiting the principle of freedom of contract, such as public order, good (business) customs, conscientiousness and honesty, abuse of rights, creation and exploitation of a monopoly in the market, equivalence of performance, equality of contracting parties, duty of care, etc. Finally, despite the identical nature of constitutive acts of the joint-stock company, given that they have a dominantly mandatory legal basis, which narrows or excludes the freedom of contract in the regulation of some rights of shareholders in the company, the issue of special legal institutes is also considered enriching the lack or narrowing of the freedom of contract of shareholders with special legal institutes which, by the will of the law (to a lesser extent by the free will of the company shareholders – e.g. voting contracts, special shareholder benefits) adapt this form of a company to the interests of shareholders (while preserving the principle of equal treatment of shareholders or equal treatment of shareholders of the same class).