Market liquidity obligation

The Market Liquidity Obligation (MLO) is a market making requirement designed to facilitate transparency and liquidity in the trading of electricity futures contracts relating to a forecast reliability gap. 

The MLO commences when the Retailer Reliability Obligation (RRO) is triggered and provides a source of qualifying contracts for liable entities to purchase to help meet their RRO contracting requirements.

MLO determinations and variations are made by the AER in accordance with the Interim MLO Guidelines.

Go to the Interim MLO Guidelines

The AER facilitates an online RRO Generator Portal to streamline the provision of generator information. 

If you believe you should have access to the portal, please contact the RRO team. The AER has also published a guide to assist market participants in using the online portal. Any questions about submitting information through the portal can be directed to the RRO team at RROaer [dot] gov [dot] au (RRO[at]aer[dot]gov[dot]au).

Go to our RRO Generator Portal user guide

The National Electricity Rules require the AER to establish, maintain and publish the MLO register in accordance with the MLO Guidelines. 

Market participants that have scheduled generating units or scheduled bidirectional units in their portfolios are reminded of the requirement to update the information in the RRO portal within 10 business days in the event the details of their scheduled generating or bidirectional units change. This is to ensure the MLO register remains accurate. 

This is necessary for all participants with scheduled generating units or scheduled bidirectional units, not only those existing MLO generators and MLO groups.

If you have any questions about the MLO register, please contact the RRO team at RROaer [dot] gov [dot] au (RRO[at]aer[dot]gov[dot]au).

Latest updates to the MLO register

The MLO register was updated in July 2026. The following changes have occurred:

• New generation information including the Waratah Super Battery in NSW, and Bungama BESS and Clements Gap BESS in South Australia.
   
• Sembcorp Industries Ltd has replaced Pioneer Sail Australia Pty Limited as the controlling entity for the relevant Alinta Energy facilities in Victoria (Bairnsdale and Loy Yang B).

Go to the MLO Register - July 2026

ASX 24 is currently the only approved MLO exchange on which MLO groups and MLO generators and liable entities can trade MLO products. 

The annual review process for the MLO exchange is set out in the AER’s Interim MLO Guidelines and clause 4A.G.23(f) of the National Electricity Rules (the Rules). 

The AER completed its annual review of the MLO exchanges for 2025 in September 2025 and concluded ASX 24 would maintain its registration as a MLO exchange.

In July 2025, the AER revoked FEX Global's MLO exchange registration following its notification of resignation as a MLO exchange and because it no longer satisfied the criteria set out in clause 4A.G.23 of the Rules.