Our preliminary work on the 2015/16 IM review began in February 2015, when we sought interested parties' views on the scope, timing and focus for the review. Our review formally commenced in June 2015, when we set out the scope, process and timing for the 2015/16 IM review.

In December 2016 we reached decisions on all IMs within the scope of the 2015/16 IM review, except for three areas:

  • we reached decisions on the Transpower Incremental Rolling Incentive Scheme (IRIS) in June 2017
  • we reached decisions on the customised price-quality path (CPP) information requirements for gas in December 2017
  • we reached decisions on the related party transaction provisions in December 2017.

Final decisions

The input methodologies (IMs) were first determined in December 2010 for specified airport services, electricity distribution and transmission, and gas pipelines. We are required to review the IMs every 7 years. We completed our review in December 2016.

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Process and consultation

The input methodologies (IMs) were first determined in December 2010 for specified airport services, electricity distribution and transmission, and gas pipelines. We are required to review the IMs every 7 years. We completed our review in December 2016.

Read more