Which attribute is not mandatory for proprietary orders?

In the context of proprietary trading on platforms such as Eurex, certain attributes are essential for executing and identifying orders, while others may not be mandatory. The correct answer highlights that the Client ID as a short code is not required for proprietary orders.

When proprietary traders place orders, they are typically trading on their own behalf and not on behalf of a client. Therefore, certain identifiers that are crucial for client-related trades, like the Client ID, become less relevant. Instead, the focus shifts to ensuring that the proprietary nature of the order is flagged appropriately to distinguish it from client orders.

On the other hand, attributes like the flagging of proprietary orders, execution IDs, and investment IDs serve critical roles in order management and reporting systems. These identifiers help facilitate proper tracking, regulatory compliance, and management of the orders executed by the trading firm.

This understanding of the necessity of various identifiers in different contexts helps clarify why the Client ID as a short code is not mandatory for proprietary orders in this scenario.