The weighted average cost of capital (WACC) is a key input for calculating the revenue requirements and setting prices for many of the businesses we regulate. The WACC is the weighted average of debt and equity costs required for a benchmark efficient business to invest in necessary infrastructure.
If we set the WACC too high, customers would pay too much and the regulated business could be encouraged to over-invest. If we set it too low, the business’ financial viability could suffer, and it may under-invest. Neither outcome is in the long-term interest of customers.
We use a standard method to determine the WACC in our pricing reviews – the 2018 WACC method.
In addition, we publish a number of tools and information sources to assist stakeholders in replicating our WACC decisions. These include:
- Our WACC model spreadsheet
- A bi-annual update of market data used to calculate WACC in February and August of each year.
- Our Uncertainty Index model
- Our True-up calculator and model guide. Our true-up calculator contains instructions on how to calculate the true-up and how to estimate the cost of debt during the transition to the trailing average.