Amendments to the Gas Input Methodologies (IMs) – WACC Percentile Adjustment

This page contains documents relating to amendments to the gas input methodologies arising from a High Court decision on the WACC percentile adjustment in August 2026.

The High Court has issued orders requiring amendments to the Gas Distribution Services Input Methodologies and Gas Transmission Services Input Methodologies in relation to the WACC percentile adjustment.

The amendments are set out in the Court's orders. To support transparency and accountability, we have also published the Court's judgment and Consistency Accountability Statements for the gas distribution and gas transmission input methodologies.