STC trading is the sale of registered certificates by the people who created them, usually installers and their agents, to the businesses that need them, mainly electricity retailers. It happens in two places: the Clean Energy Regulator’s fixed-price clearing house, and the open market where traders quote a daily rate. The difference between those two venues is the entire economics of the business.
At the time of writing the spot market has been roughly $38 to $40 per STC, while the clearing house pays a fixed $40 ex GST. That narrow gap is what you pay for speed. If you understand what the gap buys, you can judge any trader’s offer in a minute.
The market in one paragraph
Demand is set by law: retailers must surrender a number of STCs each year in proportion to the electricity they sell. Supply is whatever installers create. When supply runs ahead of demand, spot slips under $40; when it tightens, spot moves toward $40. Because the clearing house will always buy at $40, the price cannot meaningfully exceed that, and the ceiling anchors everything. See what an STC is worth in 2026.
Venue 1: the clearing house
The clearing house is run by the regulator inside the REC Registry. You list registered certificates and they are bought at $40 ex GST on a first-in, first-served basis. There is no negotiation, no fees from a trader and no price risk. The downsides are time and uncertainty: payment follows a queue, and you cannot plan around a specific day.
Venue 2: traders, brokers and agents
A trader quotes a rate, takes your registered certificates (or acts as your agent and creates them for you) and pays you. The rate is typically a little under $40. In return you get a defined settlement time and, with good traders, help with the claim. Terms differ:
| Term | What to ask |
|---|---|
| Rate | Published daily? Locked when? |
| Days to cash | One day, ten business days, “when the registry clears”? |
| Fees | Any per-claim, admin, registry or monthly fee? |
| Cancellation | Who bears the loss if certificates are cancelled later? |
| Pre-check | Is each claim reviewed before lodgement? |
The words “broker”, “aggregator” and “agent” are used loosely. The answer on aggregator vs broker sorts the language out.
Rate lock: the detail that matters
A published rate is only useful if it is held for you. Some traders quote a rate that changes before your claim is processed. Others lock it on a specific event. Ours is locked on lodgement of a complete claim. The point of a lock is to remove the price risk between the day you finish the job and the day you are paid. If the rate can move after you have lodged, you have been quoted a hope, not a price.
Compare the effect with a worked example. A 6.6 kW zone 3 job earns 45 STCs. A $1 move in the rate changes the payment by $45 per job. Across 200 jobs a year, a $1 swing is $9,000.
Settlement: what it costs you to wait
Settlement time works like interest on your own money. Take 100 jobs a month with an average of 45 STCs at $38, so $171,000 of certificate value each month. If your buyer pays on average ten business days after lodgement, you are carrying about two weeks of that volume, roughly $85,000, at any moment. If you are paid next day, the average exposure is a few thousand dollars. See how long STC payment should take.
Who is on the other side
Retailers buy through traders, agents or the clearing house. Some large installers sell direct to a retailer under a volume contract, but most small and mid-sized crews do not have the volume to negotiate that. A trader pools many installers’ certificates and sells them on, which is why scale matters in the rate card.
Fees and the “net rate”
Some traders quote a high headline rate and then take fees per claim or per certificate. Always calculate the net: rate minus fees, divided by STCs. We charge zero fees, so the published rate is what lands. The answers on STC trader fees and agent fees explained show where fees hide.
Risks worth naming
- Counterparty risk: the buyer fails to pay. Prefer buyers with a long track record and ask how long they have traded.
- Cancellation risk: certificates are later cancelled after an audit. Read the contract.
- Price risk: the market moves while you hold unsold certificates.
- Timing risk: deeming period steps and the 12-month window.
Common mistakes for new installers
Treating the clearing house as the default. It is a fine backstop, but a business that depends on a queue for cash is borrowing against an unknown date. Use it when you want the full $40 and can wait.
Assuming rates are equal because they look close. A rate card is only meaningful with its terms attached: the lock, the settlement days, the cancellation clause. Two traders can be 20 cents apart on paper and thousands apart in practice.
Ignoring the compliance step. A rejected claim has no price at all until it is fixed and relodged. A trader that pre-checks claims is selling you certainty as well as a rate. Our rejection reasons guide lists what a pre-check catches.
Forgetting the calendar. Every 1 January, the deeming period falls. A rush of jobs in December is common, and so is a wave of paperwork in January. Plan your claim capacity for it.
A simple way to compare two offers
Write down, for a standard 6.6 kW job, the net cash you receive and the day you receive it. Offer A pays $38.20 a certificate, 45 STCs, ten business days, with a $10 per-claim fee: (45 x 38.20) - 10 = $1,709 in about two weeks. Offer B pays $37.90, no fee, next day: 45 x 37.90 = $1,705.50 tomorrow. The first looks better on the rate, and it is $3.50 ahead per job, but B returns your cash twelve days sooner. If your cost of money is a bank overdraft at 12 per cent a year, twelve days on $1,700 is about $6.70. On the numbers B wins, and it has no fee surprises either.
What to do next
If you are comparing offers, use the checklist for choosing a certificate trader. Next read how STC trading works for the day-by-day mechanics, and the pillar guide for the full installer overview. Today’s rate is on the pricing page, and start trading takes you through account setup.