On 26 May 2026 the AER released the final determination for the Default market offer for 2026–27 (DMO 8).

ACIL Allen supported us in the design of a forecasting approach for wholesale and environmental costs. The report Wholesale energy and environment cost estimates for DMO 8 final determination by ACIL Allen was published alongside the final determination on 26 May 2026.

We have published a spreadsheet of ACIL Allen’s modelling data for the cost of energy for interested stakeholders to understand its forecasts. The information contained in the modelling data is also set out in the ACIL Allen report for our final determination.

On 26 May 2026 the AER released its model for calculating DMO tariff caps and prices for 2026−27.

As set out in the DMO 8 final determination, the AER uses a cost build-up approach to calculate the DMO tariff caps, taking into account costs for wholesale electricity, network, environmental and retail costs, and applying a retail margin. We have assigned recovery of fixed costs to the daily supply charge and recovery of variable costs to the usage charges in the DMO tariffs.

The information contained in the model is set out in the DMO 8 final determination, and we have published the model to provide stakeholders with additional transparency on how we have calculated the DMO tariff caps and prices for 2026–27.

We requested AEMO to provide the interval meter data used to simulate the load profiles. This data has been published as supporting information alongside the DMO 8 determination. The data provided is at 30-minute intervals with both customer types aggregated (residential and small business), by DMO region. This provides transparency regarding a key input to our wholesale energy cost modelling, allowing stakeholders to consider inputs in more detail.

Additionally, to forecast the controlled load profiles for DMO 8, we requested interval meter controlled load profile data from distribution network service providers in each DMO region. This data has also been published alongside the DMO 8 determination.

The DMO 8 assumed patterns of supply were published in Excel format as part of the non-market sensitive update on 15 May 2026.

The AER and Australian Competition and Consumer Commission (ACCC) have published a joint compliance bulletin to help electricity retailers understand and comply with certain obligations following changes to the Electricity Retail Code.

We have prepared an information kit to help explain the elements of the Final DMO 2026-27.

On 26 May 2026 we published an updated version of the Solar Sharer Offer fact sheet originally published in March 2026, to explain the new SSO framework and design.