“Who sets the STC price” and “who determines the STC spot price” are asked as though a single body issues a number each morning. There is no such body. There are two prices, and each has a different owner.
The fixed price: the government
The Clearing House price of $40 excluding GST is set in regulation and administered by the Clean Energy Regulator. That price does not move with the market. It is the ceiling in practice, because a buyer who can always get a certificate at $40 will not pay more on the open market. We explain this in why the price is capped at $40.
The spot price: buyers and sellers
The spot price is simply the price at which certificates actually change hands on the open market. Participants include:
- Certificate traders and brokers, who buy from installers and agents and sell to retailers.
- Liable entities, mostly electricity retailers, who need certificates to meet their quarterly obligation.
- Large installers and aggregators with enough volume to deal directly.
Brokers then publish a daily or weekly reference price based on the trades they see. Those figures are indicative, which is why two sources can differ by several cents on the same day. At the time of writing the spot market has been roughly $38 to $40.
The rate you actually get: your trader
The price an installer receives is neither the Clearing House price nor the broker’s spot print. It is the rate your trader publishes, minus whatever the trader charges, locked at a time you can verify. Energy Merchants publishes its rate daily on the pricing page, locks it when a complete claim is lodged, and charges no fees. Other traders vary in how and when they lock, so read the contract. Our trader contract terms checklist shows what to look for.
Why the spot price sits where it does
Because the ceiling is fixed, the spot price is really a measure of how far below $40 the market is willing to go. That gap reflects supply, how long it takes to sell, and how much risk buyers carry. We cover the drivers in what drives STC prices.
What does not set the price
Customer rebate quotes, state schemes and solar retailers do not set the STC price. Retailers quoting an STC “value” on a solar quote are simply applying their own assumption, often an estimate close to the ceiling. See how STC prices appear on quotes for why they differ from what you receive.
What this means for installers
You are a price taker but not a price victim. The market is competitive, the ceiling protects you from a collapse in practice, and a published, locked rate lets you quote with confidence. Compare traders on locked rate and settlement time, and see how STC trading works and what an STC is worth in 2026 for context.