I see, this explains the volatility in VISA 10 and 5 minutes prior to the close today. Thanks, i should have realized this myself Looks like i also need to find a way to get live access to the imbalances to understand it even better.
How do you define "impact?" - how much closing price will move if your order creates/increases imbalance by N shares?
Yeah, effectively. So the expected return from say the imbalance coming out to the close price conditional on the imbalance as a function of volume. There often are other variables like volatility to improve the model but by far for the close the most important one is simply the imbalance divided by a measure of volume (adv or just today's volume).
Have you tried CBOE's Market Close? Since they don't advertise/publish their imbalances, I would assume they don't have enough volume to make a difference. http://cdn.batstrading.com/resources/membership/Cboe_Market_Close_FAQ.pdf
I often find it helpful to split orders to execute at different times just prior to the close, as opposed to being caught in the automatic doors as the train leaves for the day. A few brokers, such as IB and TDA, offer conditional-at-time orders.
I have been away for some time so hence the late reaction. I do understand your point, however my strategy is based on closing price, even a change of lets say 0,2% in the last 10 or 15 minutes wouldn't matter much. The main reason why i like the MOC orders is scalability, even extreme volumes and extreme imbalances have minimal impact on the market. Such volume is extremely hard to trade during the day.