The subject of the study is to find ways to improve the usefulness of accounting data for its owners. The article highlights the interpretation of the concept of «owner of the organization»: the owners of all units of property, only the holders of the right to vote; only shareholder. It is concluded that financial statements are both a mandatory and a voluntary source of information for transactions on the transfer of ownership of a share and share. The situations of using accounting data on a mandatory basis are highlighted: to calculate the actual value of a share when a participant leaves the company or is expelled from it, and on a voluntary basis: to determine the transaction price when buying and selling shares or shares when it is impossible to evaluate the enterprise as a business. The author proved that the principle of conservatism does not allow to calculate the adequate property value of a share or share according to the organization’s financial statements.It is concluded that the calculation of the actual value of the participant’s share should be based on the assessment of the value of the enterprise as a business. The necessity of harmonization of normative documents regulating the procedure for the functioning of legal entities and the procedure for the formation of financial statements is substantiated.