We undertook a review of our approach to how we determine reasonable rates of return for the businesses subject to our regulatory regime. Our review was based on wide-ranging research, regulatory best practice, economic principles and thorough analysis. We also consulted with stakeholders.
We published an updated version of the final paper in 2024 after making a few minor changes. The notice below provides more detail of these changes.
A workbook with an example of a cost of debt calculation is also available below, after the final report.