The Commerce Commission's straitjacket approach to regulating returns on Auckland International Airport's assets is strangling the country's main gateway airport from necessary expansion.
In mandatory filings lodged on Thursday, AIA said it was basically ignoring the commission's acceptable weighted average cost of capital (WACC) requirements where it believes they can't be reasonably supplied.
At the same time, the airport released its new charges for airlines and passengers using both the international and domestic terminals over the next five years, as it is required to do every three years as part of its obligations to the commission, which regulates returns on monopoly assets.
Other industries monitored by the commission include electricity, gas and telecommunications networks, ports and airports. Many in these sectors are also challenging the commission's input methodologies for determining acceptable rates of return on capital.
Ministers and the Ministry of Business, Information and Employment have been lobbied on widely perceived shortcomings in the way the commission is implementing its role.
The airport's main argument is that the commission's adherence to an inflexible WACC calculation is wrong because "a precise return cannot be calculated and ... the WACC must be considered within a range".
The airport's biggest beef is the commission's decision not to include undeveloped airport land when it considers WACC calculations, leading to a perverse discouragement to develop the airport's delayed Northern Runway project.
"Auckland Airport is concerned that the commission's methodology may not deliver commercially acceptable outcomes for the airlines in the future due to the step change in pricing implied by it," AIA's acting chief executive Simon Robertson says in the introduction to its filings.
The airport says its proposed tariff increases over the next five years are "flat in real terms", and in "the middle of the pack" at just under $30 in total costs per customer, and equate to an 8.475 per cent WACC, compared to the commission's requirement for 8.04 per cent expectation.