PIAC responded to the AER’s consultation draft amendments for the Regulatory Investment Test for Transmission (RIT-T) and Distribution (RIT-D) application guidelines. PIAC supports the explicit obligation in the Rules for a Transmission Network Service Provider (TNSP) to reapply the RIT-T if a material change has occurred, and for the TNSP to be allowed to apply to the AER for an exemption from this in limited cases. However, it is unclear to PIAC whether there is any recourse for stakeholders to challenge a TNSP’s decision to not reapply the RIT-T, as may be appropriate when, for example, a stakeholder considers a material change has occurred which warrants reapplying the RIT-T but the TNSP has not done so. PIAC considers that the ability to challenge the TNSP’s decision is important and recommends that the AER make this ability explicit.