def, Thx. I didn't ask the names of the staffs who answered any calls. In the first call, a female officer told me that the order *might be* submitted several times. But in the 2nd call, a male officer said the order was submitted *only once* and the delay was totally due to HKFE (it's about 5 o'clock in the afternoon, and seems he's hurry to getting off). He's also *not sure* that MKT orders are offset by 0.3% to current price. I'm confused here. If simulated MKT STOP is 0.3% offset to current price, which is more than 80 points these days. I am definitely sure that during that 3-second delay, the price didn't fall more than 15 points. Why the LMT order was not executed immediately if my ASK price was more than 65 points lower than the best BID? Why does IB server need to submit the order several times? So there must be something wrong in the above logic. Either the 0.3% offset is not true or IB's MKT orders are totally unreliable.