Installers ask this as if there were three different products. There are really two questions: who is legally allowed to create your certificates, and who ends up paying you.
The legal role: registered agent
When you sign an assignment form, you give someone the right to create STCs for your installation. To use it they must be a registered agent with the Clean Energy Regulator (or a registered person who is the system owner). That status is public and checkable. See what the REC Registry is and the assignment form.
The commercial labels
Aggregator. Pools many installers’ claims, often supplies software for photos and forms, and sells in bulk. The business model leans on volume and a margin between what it pays you and what it sells for. Some are pure software platforms; some run their own agent registration.
Direct trader. Buys certificates on its own account and trades them with retailers and other buyers. It often takes the registry risk itself.
Broker. Introduces buyers and sellers for a commission without necessarily taking title. See broker vs aggregator and what a broker is.
A business can be all three. The label tells you less than the answers to the questions below.
Questions that matter more than the label
- Who holds the registry account? If your STCs are created under someone else’s registration, their standing matters. Check it on the CER website.
- What do I get paid, and when? Ask for the rate in writing, when it is locked, and the settlement time after lodgement.
- What comes off the rate? Per-certificate fees, admin charges and registry costs should be listed. See aggregator fees.
- What happens to a failed claim? Some pass the cost back to you, some do not.
- Who checks the claim before lodgement? Pre-checks cut failures.
Aggregator vs direct trader
A direct trader tends to have shorter chains: you, the trader, the buyer. An aggregator chain may have an extra link, and each link wants paying. That is not always worse: some aggregators offer excellent software and tight compliance. The honest comparison is on net dollars per STC, days to cash and failure handling, not the title. For a worked comparison, see how to compare platforms.
What this means for installers
Judge on the numbers: a published rate, a locked rate, a stated settlement time and zero surprises. Energy Merchants is a direct, zero-fee desk backed by REC Traders, with a named account manager. See today’s rates, how it works, and the switching guide if you are comparing providers.