Input methodologies (IMs) underpin the information disclosure requirements that Auckland, Christchurch and Wellington International Airports are subject to.

The IMs cover matters like how assets are to be valued, depreciated and revalued, how we estimate the cost of capital, how tax should be treated, and how common costs should be allocated where businesses provide both regulated and unregulated services.

The IMs for airports were originally determined in 2010 and there have been amendments made to the IMs since then.

We are required to to review the IMs at least every 7 years. We completed our first review of the IMs in 2016, and you can find more information about this below.

The reasons for the current IMs for airports are captured in the reasons papers for the original IM determination and all subsequent amendment determinations – these can be found via the links below.


2023 input methodologies review

We are in the process of reviewing the current IMs. We began the review on 23 February 2022 by issuing the required notice of intention which sets out a high-level process and scope for the review. We intend to complete the review by the end of December 2023.

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Other past amendments and clarifications

These are the past decisions we have made related to input methodologies for Airports, and the process of how we got to these decisions.

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Current input methodologies for airports

These are the current input methodologies that apply to Auckland, Christchurch and Wellington International Airports.