How are SwissAtMid orders executed?

• A. Quantity-time priority
• B. Size-based priority
• C. Random selection
• D. Price-time priority

Answer: (A)

SwissAtMid executions happen at the mid price between the current best bid and offer. Since all potential matches share the same price, the way the engine decides which orders cross first is based on size and time. The largest mid-price orders are given priority to maximize the amount traded in one cross, and if two orders are the same size, the one that arrived earlier gets priority. This helps improve overall liquidity while keeping fairness through time ordering.