Economic regulation in energy activities is motivated by the need to control the activities of "natural monopolies" which are essential for the development of market competition and the protection of the interests of end customers. Regulated energy activity of gas distribution is one of such concession-type monopolies. The regulator, with the given criteria and methodologies, ensures the incentive service price to the end customers, and at the same time provides the distributors with a return on investment from regulated assets, i.e. assets used for performing regulated activity. The main goal of the research of this specialist post-graduate work is to analyze the existing model and determine the relationship between the regulated assets of the company, connection to the operations of the gas distributor and the impact of the regulator. The research methods in this work were classification, analysis and synthesis, and finally the method of comparison of publicly available data from the business operations of regulated entities in gas distribution as well as regulatory decisions and data related to the subject of research. There are several models of economic regulation in force, but the incentive regulation of maximum allowed revenue using CAPM model is the most used and important and in all EU countries. The paper covers two regulatory periods and the regulated assets of gas distributors in the Republic of Croatia, and it was established that the success of their business performance is directly correlated with the amount of regulated assets. In addition to the return on the regulated assets, significant importance of the allowed operating costs determined by the regulator was determined. It is concluded that in the case allowed operating costs are low or in conditions of major inflationary disturbances in the market, simultaneously with a drop in distributed gas volumes without the possibility of flexible changes in tariff items, the business of gas distributors will not be satisfactory even with possible adequate returns on regulated assets. At the same time, the work provides projections of future business and proposals for measures to improve the performance of gas distributors.