On 29 April 2005 the ACCC released its decision regarding TransGrid's revenue cap application for the regulatory period 2004 to 2009.

The ACCC's decision draws on consultancy reports, submissions from interested parties and the analysis of data and information presented to the ACCC in the course of its deliberations. The decision considers regulatory issues such as the opening asset base, the weighted average cost of capital and the treatment of capital and operating expenditure.

On 2 February 2007, the AER decided to revoke and substitute TransGrid's 2004-09 revenue cap under clauses 6.2.4(d)(2) and 6.2.4(e) of the National Electricity Rules. TransGrid requested this re-opening in November 2006 on the grounds that there was a material error in setting its revenue cap in 2005.