Partial Execution Creates Multiple Trades
At this point, the reported price is $11 set by the most recent recorded trade.
The book currently contains:
- one bid with no matching ask
- no asks
Stage 1. A Larger Ask Arrives at a New Price
Event: At a seller submits an order to sell 5 apples at $14 each.
The order is recorded in the asks ledger.
No trade occurs.
There is no bid priced at $14 or higher, so the new ask does not overlap with any existing buy order.
The reported price remains $11 because no trade has occurred and nothing has been added to the trade tape.
Stage 2. A Smaller Buy Order Arrives
Event: At a buyer submits an order to buy 2 apples at $14 each.
The order is recorded in the bids ledger.
The incoming buy order overlaps with the existing ask priced at $14
Because the prices overlap and quantities exist on both sides, a trade can occur.
Stage 3. Trade Execution
Two apples are exchanged at $14 per apple.
As part of this execution:
- A - the trade is written to the trade tape at and
- B - the matched sell order is reduced from 5 apples to 3 apples, and
- C - the matched buy order is removed.
What Happens After Partial Execution
The buy order is fully executed and removed.
The sell order is only partially executed, so it remains open with a smaller remaining quantity:
- the remaining amount is 3 apples
- the price remains $14
- the arrival time remains
No other orders are affected.
Conclusion
Partial execution occurs when the quantities on the two sides of a match do not fully offset each other.
In this case:
- the buy order was fully consumed,
- the sell order remained open with reduced quantity,
- the trade was recorded only for the executed quantity.
Each execution creates its own entry in the trade tape.
A single order can therefore produce multiple trades over time.
Trades are recorded per execution, not per order.