in my iron condor on SPY,April 24th, 211.5C 212.5C, 207p 206p, l had tried to close it at prices which were the best bid at the time,(in IB have to select BID to close and ASK to open) yet they didnt execute. eventually l entered a price of -0.39 and it did get executed, when the mid price was a superior , -0.37. kindly see attachments. can anyone explain this?
Those prices might have been from different exchanges with some customer orders that no mm wanted to match.
In the first screenshot both bid and ask are at -0.38 which is strange. Stale quotes? As for not getting a fill at the bid, I've never experienced that, but I have not been filled at the Ask many times with flies. I've watched price move to match my buy order, stay there a while and then move away without filling my order. I just figured it was because 1 leg couldn't execute, which is probably the case with your order. The times I'll always get a fill for complex spreads is when the market trades through my price.