IB has an unusual behavior with odd-lot OCA orders on NYSE stocks. For example, say we have a 40 share short position in XYZ, with a OCA order consisting of a BUY 40 XYZ @ 55.00 STOP GTC and a BUY 40 XYZ @ 52.00 LIMIT GTC. These two orders bracketed yesterday's closing price of 54.00. Today XYZ trades above 55.00 and activates the STOP order. However, the IB TWS will return an error message stating to the effect that opening odd-lot orders are not allowed. The STOP order will be subsequently cancelled, leaving only the LIMIT order active. In this example, we have an outstanding open short position in XYZ at the time, thus this behavior is not correct, in my opinion. If odd-lot OCA orders worked for closing existing NYSE positions, it would make IB's TWS much more usable in my opinion for those of us trying to scale out on odd lot sizes. In my past discussions with IB tech support, they have acknowledged this as a known behavior. If you concur that this behavior should be changed, please let IB Management know. Their e-mail address is ibmgmt@interactivebrokers.com. -- ITZ.
Similar to this problem, if you have multiple mixed-lot orders in an OCA group, I've seen a fill on one of them not decrement the number of shares in the other orders. I think the situation was something like: I'm short 55 shares of XYZ. I want to cover the 55 and go long another 100, so I have 3 orders to buy 155 shares via three ECNs at different prices, in an OCA group. One of them gets hit for 36 shares, leaving it with 119 shares remaining to buy. The other orders, though, remain at 155 instead of decrementing to 119. I want to point out that none of this odd-lot crap is intentional on my part. It's simply a fact of life when posting orders on ECNs (like Island) that don't offer odd-lot protection. Personally, I'd be happy if odd-lots were sent back to the warm place from which they came.