diff --git a/ib_async/wrapper.py b/ib_async/wrapper.py
index 4b21b3f..65e1e5f 100644
--- a/ib_async/wrapper.py
+++ b/ib_async/wrapper.py
@@ -539,6 +539,7 @@ def completedOrder(self, contract: Contract, order: Order, orderState: OrderStat
         contract = Contract.create(**dataclassAsDict(contract))
         orderStatus = OrderStatus(orderId=order.orderId, status=orderState.status)
         trade = Trade(contract, order, orderStatus, [], [])
+        self._results.setdefault("completedOrders", [])
         self._results["completedOrders"].append(trade)
 
         if order.permId not in self.permId2Trade: