Help needed: Partial fills of stop orders with IB

Discussion in 'Order Execution' started by Rogue, Apr 21, 2009.

  1. Rogue



    I am using IB as a broker and it happened to me quite a few times in the last days that a stop-sell order was only executed partially. I don't mean it got split up in different parts and they summed up to the total order size, but the total executed quantity did not match the order quantity. So I had remaining stock in my account whih should have been sold.

    So far I am using plain stop sell orders and I wonder how I can prevent that. I am trading ETFs with high liquidity, so that should not be a problem.

    Did you experience similar things? How do you deal with that?

    Btw, I am using odd lot sizes, as the quantity is calculated automatically risk based. I am not sure if that could be part of the problem and simply trading 100s would be easier. Allthoug today I got 221 shares of 228 filled. So not really a round number as well.

    Thank you in advance

  2. piezoe


    Try rounding your odd lots up or down to the nearest multiple of fifty shares.
  3. maxpi


    Are those NYSE or NASDAQ stocks? I guess you are using stop-market orders and not stop-limit orders?
  4. Rogue


    I use the SMART routing in IB, mostly they are routed to ARCA, I saw that the last batch was routed to ISLAND this time.

    I am not that familiar with the routing, I actually don't know what ISLAND means.

    Yes, I am using STOP MARKET orders, correct.
  5. ISLAND is INET, and many ECNs may give you fills as small as 1 share. Try to use All-or-None orders if you want to prevent partial fills, but that would worsen execution quality.

    When your order got triggered? If it was around 4:00pm and you didn't have "Fill outside RTH" option enabled, IB SmartRouter could probably just stop splitting after 4:00pm.
  6. Rogue


    No, it was in the middle of the day, around noon.

    I don't trade outside RTH, that is correct.

    When I saw the imcomplete fill a few minutes later, it was no problem to close the position with a new order (worse price and double commission, though).

    I talked to a few people and some of them said, I can EXPECT to get filled completely in liquid symbols, when I trade market. Would you agree to that?
  7. Market orders submitted during RTH shall be filled, period. IB Smart Router is a different story. Where the order in question was routed to? Use "View Audit Trail" in TWS to check the order properties (FIX msg) to verify it has right stuff, and if not, call IB.
  8. I doubt whether you should be trading at IB, if you don't know what ISLAND means. You need to learn more about order routing and execution, before you are ready to do the type of trading you are attempting to do.

    Order execution bugs, in IB's software, are more likely, for odd-lot orders, because their execution logic is more complicated than that for round-lot orders. It sounds like you may have encountered just such a bug, but if so, your lack of knowledge will add to the other inevitable barriers to getting such a problem recognized by IB.
  9. DAV

    DAV ET Sponsor

    Please check your inbox, I PMed you last week to ask for details so we could investigate and I haven't heard from you.

    If anyone else is experiencing this problem please contact me.