The topic of the paper is the company's own shares. Own shares are shares held by the issuing company. As there is a specific legal situation with own shares where membership in the company is not held by a third natural or legal person, but the company itself could exercise these rights and obligations, it is necessary to regulate in detail the conditions under which the company may acquire its own shares. Otherwise, there could be a potential abuse of that institute. Acquiring own shares may have certain advantages but their acquisition contrary to legal rules and principles of market practice may represent risks and legal consequences for the company. Therefore, the acquisition of own shares is prohibited in law. However, the company is still allowed to acquire its own shares in specified cases based on the law or based on the decision of the general assembly. When acquiring one's own shares, we distinguish between two legal transactions, the obligatory legal transaction that assumes the obligation to transfer shares (titulus) and the legal transaction of transferring shares (modus). When the company acquires its own shares contrary to legal rules, the legal deed (titulus) is void because they do not fulfill the prerequisites for acquisition, but the company will still validly acquire shares if the legal deed of share transfer (modus) is valid. The legal consequences that occur during the illegal acquisition of shares are the alienation or withdrawal of the shares within a certain period, and potentially the responsibility of the board members, that is, the executive directors for such an acquisition.