By the way, the easiest way around this latency arbitrage in simulated trading games is to have all trades occur at the published closing auction price for the

By the way, the easiest way around this latency arbitrage in simulated trading games is to have all trades occur at the published closing auction price for the next closing auction after the trade is placed. A trade for IBM.N at 09:43 America/New_York or 15:55 America/New_York occurs at that day's closing price. A trade for IBM.N at 16:05 America/New_York occurs at the next day's closing price. Disallow placing or canceling orders within 5 minutes either side of the particular equity's market close in order to prevent latency arbitrage and reduce disputes.