Fills & Settlement
A fill is the record of a matched trade between two orders. When the matching engine pairs a buy order with a sell order at an agreeable price, it creates a fill for each side. Fills are the primary output of the trading engine and the basis for settlement.
What a fill is
When your order matches against a counterparty order, the engine:
- Determines the matched quantity and clearing price
- Reduces the
workingQuantityon both orders by the matched amount - Creates a fill record on each order
Each fill records the exact terms of the trade — price, quantity, and counterparty — at the moment of matching. Fills are immutable once created. They cannot be reversed, amended, or cancelled.
Partial fills
Not every match consumes your entire order. If the best available counterparty order has a smaller quantity than yours, the engine matches what it can and leaves the remainder of your order in the queue.
For example, if you place a buy order for 10 MW at $85/MWh and the best resting sell is for 4 MW at $84/MWh:
- A fill of 4 MW occurs at $84/MWh
- Your order transitions from
workingtopartial - Your
workingQuantitydrops to 6 MW - Your
filledQuantityrises to 4 MW - The 6 MW remainder stays in the queue at $85/MWh
Additional fills can occur on the same order as further matching counterparty orders arrive.
Fill properties
Each fill record contains:
| Field | Description |
|---|---|
id | Unique identifier for this fill |
price | The price at which the trade matched ($/MWh) |
quantity | The volume matched in this fill (MW) |
orderId | The ID of your order this fill belongs to |
matchedOrderId | The ID of the counterparty order matched against |
timestamp | Unix timestamp of when the fill occurred |
tradeTime | Human-readable time of the trade in Pacific/Auckland time (HH:mm:ss.SSS) |
When fills are delivered to the front end, they include additional context for display:
| Field | Description |
|---|---|
contractCode | The contract identifier (e.g. OTA-ON-MAY25) |
node | The GXP node (OTA or BEN) |
profile | The trading period profile (ON, EP, MP, BASE, PEAK) |
aggressingSide | Which side (buy or sell) was the aggressor in the match |
counterpartyName | The entity name of your counterparty |
counterpartyTrader | The individual trader at the counterparty entity |
The Fill List pane
The Fill List pane shows all fills for your entity in a sortable, filterable table.
Filter toolbar
At the top of the pane you can filter fills by:
- Date — defaults to today (NZ time). Use the date picker to view historical fills.
- Contract — filter to a specific contract code.
- Side — filter to BUY fills or SELL fills only. Click the active filter again to clear it.
The fill count at the right of the toolbar shows how many fills are visible versus the total loaded (e.g. 12/47).
Columns
| Column | Description |
|---|---|
| Date | Trade date in DD/MM/YYYY format |
| Time | Trade time in HH:mm:ss (NZ time) |
| Side | BUY or SELL — colour-coded blue for buy, red for sell |
| Contract | Node · Profile · Contract code |
| Price | Matched price in $/MWh |
| Volume | Matched volume in MW |
| Counterparty | The entity you traded with |
| Trader | The counterparty trader's name |
| Fill ID | Unique fill identifier |
The colour of each row reflects the side of the trade: buy fills are shown in blue, sell fills in red.
Legend
The footer of the Fill List shows a colour key:
- Blue dot — Ask paid (you bought, paying the ask price)
- Red dot — Bid given (you sold, receiving the bid price)
Order quantity split
Every order tracks three quantity fields that together account for the full original order size:
| Field | Description |
|---|---|
workingQuantity | Quantity still active in the matching queue |
filledQuantity | Cumulative quantity matched across all fills |
cancelledQuantity | Quantity removed when the order was cancelled or expired |
These fields always sum to the original quantity. You can view them on individual orders in the order blotter.
Example — 10 MW buy, partially filled then cancelled:
| Field | Value |
|---|---|
Original quantity | 10 MW |
filledQuantity | 6 MW |
cancelledQuantity | 4 MW |
workingQuantity | 0 MW |
Settlement
The settlement price for a CFD contract is determined by the contract terms, referencing the underlying electricity spot price for the relevant trading period and GXP node.
Fills represent the agreed CFD trade price between you and your counterparty. The net payment on settlement is the difference between your traded price and the settlement (spot) price, applied to the total matched volume.
Settlement calculations and payment processing are handled by the exchange clearing process, not within the AEX platform itself. The Fill List gives you a complete record of your matched trades to reconcile against settlement statements.
Fills are final
Once a fill is created, it cannot be undone. There is no mechanism to cancel or reverse a matched trade within the platform. If you believe a fill occurred in error, contact the exchange operator.
Submitting an order at an unintended price can result in an immediate fill that proceeds directly to settlement. Always verify your price and volume before confirming an order submission.
Next steps
- Order Lifecycle — how order state changes as fills occur
- Held Orders — how to stage orders before exposing them to matching
- Market Sessions — when matching is active during the trading day