If I am filled at a price that is grossly different from the trades that are being executed at the time my trade is filled, do I have any recourse?

There is a process by which an investor can challenge a trade. As we don’t place market orders, we have never challenged a fill at a disparate price. We have, however, challenged the lack of a fill when our order has been entered at the bid or ask and has sat there unexecuted while the bid and ask do not move. We use our full service brokers to make challenges, and what they normally do is print out the time and sales record to verify the claim and then contact the trading desks, etc. We rarely win. The claim is always that the market is moving too fast. We have won a few when it was clear the order was not hit when it sat there for several minutes while the bid and ask were right in line with the order. This used to happen a lot when we traded stock splits on the announcement. We had brokers who would contact us immediately on the news. We would often have orders entered before the news was widespread. The market makers caught on, however, and once they got news of the split, they would wait and see how many orders were coming in and then jack up the option prices. We have had orders in at the ask price for four minutes while the option price did not move. Then the ask was jacked up without our position being hit. Frustrating, but hard to do anything about.