Fees are where trader comparisons get murky, because three different things get called fees. Separate them and the comparison becomes simple arithmetic.
The four ways intermediaries earn
1. The spread. The gap between what the buyer at the other end pays and what you receive. It is rarely labelled, but it is usually the largest cost. See why trader prices differ from spot.
2. Per-certificate fees. A fixed amount per STC deducted from payment or invoiced. Fees of this kind are often described as covering processing, compliance or registry costs.
3. Admin or subscription fees. Monthly platform charges, per-claim fees, minimum volumes or fees for resubmitting failed claims.
4. Registry costs. The CER charges a creation fee per STC to whoever creates them, about 47 cents at the time of writing for rooftop solar, with the first 250 free for a system owner. An agent may pass this through. See what registering costs.
How to compare
Take one realistic job. A 6.6 kW system in a zone 3 city with a 5-year deeming period creates 6.6 x 1.382 x 5, about 45 STCs. Ask each provider what lands in your account for those 45 certificates on a given day, after everything. If two quotes differ by 50 cents per STC, that is about $22 a job, and over 500 jobs a year about $11,000.
Then check the other variables:
- When is the rate locked: at lodgement, at validation, or when paid?
- What are the failed-claim rules?
- How long between lodgement and money?
- Are there cut-off times? See trader cut-off times.
Aggregator vs broker fees
A broker usually charges a commission built into the price. An aggregator more often pairs a spread with software or admin charges. Neither is wrong if the net rate is good. See broker vs aggregator and what a broker is.
What this means for installers
Ask every provider for a one-line statement: rate, lock point, deductions, settlement time. Ours is on pricing: a published daily rate, locked on lodgement of a complete claim, zero fees, and 24-hour settlement for established partners (48 to 72 hours on a first claim). For the wider field see the STC trading pillar, how it works, and the switch guide.
A note on minimums and exits
Before signing, check for minimum monthly volumes, notice periods and charges for leaving. A provider confident in its service has little reason to lock you in. The easier it is to leave, the more the provider has to earn your next claim.