The book "Price Regulation and Risk" by Michael Hierzenberger offers a comprehensive analysis of the challenges associated with price regulation in natural monopolies. It highlights the necessity of controlling companies in monopolistic positions regarding their pricing, as they do not adhere to competition-based market principles. The author examines the effects of changes in the regulatory regime on future equity costs and their significance for conducting capital market-oriented corporate valuations. By applying the Principal-Agent problem, the topic is explored in depth. Two studies, one an international secondary analysis and the other a primary analysis of Austrian regulatory policy in the energy sector, demonstrate that the transition from revenue regulation to incentive regulation leads to a significant increase in systematic risk.