def on_partially_filled_order

The lifecycle callback method called after LumiBot observes a partial broker fill. Use it for quantity-sensitive work such as incremental hedging.

Parameters:

position (Position): The updated position after applying this fill order (Order): The order object that is being processed by the broker price (float): The filled price quantity (int): The newly observed fill quantity for this callback, not the cumulative filled quantity multiplier (int): Options multiplier

class MyStrategy(Strategy):
    def on_partially_filled_order(self, position, order, price, quantity, multiplier):
        order_id = order.identifier
        previously_processed = self.processed_fill_quantity.get(order_id, 0)
        self.processed_fill_quantity[order_id] = previously_processed + quantity
        missing = order.quantity - self.processed_fill_quantity[order_id]
        self.log_message(f"{quantity} has been filled")
        self.log_message(f"{quantity} waiting for the remaining {missing}")

The later on_filled_order callback receives the remaining delta and should reuse the same idempotency state. Live callbacks may be delayed or reconstructed after reconciliation; keep the callback short and do not require a fresh broker read before acting on the supplied order and quantity.

Reference

lumibot.strategies.strategy.Strategy.on_partially_filled_order(self, position: Position, order: Order, price: float, quantity: float | int, multiplier: float)

Use this lifecycle event to execute code when an order has been partially filled by the broker

Parameters:

• position (Position object) – The position that is being filled.

• order (Order object) – The order that is being filled.

• price (float) – The price of the fill.

• quantity (float or int) – The quantity of the fill.

• multiplier (float) – The multiplier of the fill.

Return type:

None

Example

>>> def on_partially_filled_order(self, position, order, price, quantity, multiplier):
>>>     if order.asset == "AAPL":
>>>         self.log_message(f"{quantity} shares of AAPL partially filled")
>>>         self.log_message(f"Price: {price}")