Here is what they say about changing those: Market Delay - Because we use a 20 minute delayed datafeed, it is necessary to hold market orders for a certain time before being filled. We strongly recommend that this be set to 20. If it is not, there is a high probability that some orders may get stale quotes. Daily Volume Rule - Trades cannot exceed a certain percentage of volume for the day. The default value is 10% and this applies to both stocks and options. This prevents a thinly-traded stock from being traded in the simulator when it can't be traded in the actual markets.