Realistic fills, not instant click-to-fill behavior
The competition is designed to reflect realistic execution rather than instant click-to-fill behavior.
Marketable orders are generally simulated as averaged execution over the next five minutes, rather than as immediate perfect fills. Limit orders are handled according to defined fill rules and are only filled when the simulated market actually reaches or trades through the order price under those rules.
Trading activity that depends excessively on ultra-short-term execution behavior may be penalized or excluded from consideration.