Quote from Sanz:
Anyone knows how OPG orders work with IB when it comes to ETFs?
As far as I understand IB OPG's do not participate at the ARCA opening auction but rather IB tries to get a fill as close to the open price as possible. What is that "open" price? Is it auction determined? Time determined? How can IB get that price? From who?
I trade with OPG and empirically I have 0-3 cents slippage (on liquid etfs and assuming the "official" opening price) but damn me if I understand what really happens at that 1-2 cent level.
Where do you get that from?
Also, where do you get your official/native opening price information? If it's the "open" field in TWS then that displays the first trade after 9:30:00 ET, can be on ARCA or any of the ECNs so it can't be used to verify. Compare your fill price with the opening price from T&S, almost always the largest block trade in the first 10 minutes after open.