Changing quantity on a partially filled limit order!


After I get a partial fill on my limit order, if I change the 'quantity' of this order, am I changing the pending quantity or the overall quantity?
  • unoffocial
    Taking care of partial orders is one of the edge case scenarios in my automation system, and would appreciate an answer. Testing the API call from my end will require huge effort to set-up the partial-trade in live trading.
  • sujith
    If you are modifying partially filled order's quantity then you are modifying overall quantity.
    If you modify quantity more than total order quantity then your order will be canceled.
    Consider a scenario wherein you placed an order for quantity 1000 and 300 is executed and now if you edit your quantity to 300 then order will be canceled and if you modify it to 400 then your total order quantity becomes 400.
  • sujith
    If you increase quantity to more than original order quantity then order will be canceled.
  • unoffocial
    Great! Thanks a lot for the answer.

    I'll summarise, please correct me if I'm wrong.
    If I get a partial fill of 300 out of 1000:

    A: If I modify quantity to 300, then the order is closed. No further execution.
    B: If I modify it to 400, the order quantity is adjusted and waits for another 100 shares fill.

  • sujith
    Yes, you are right that is the expected behavior.
  • rs1914
    Hi @sujith, I think there is a bug in order modification.
    I came across this scenario:
    I put a limit sell order for 50 quantity with disclosed quantity as 6. After a while 48 got filled. With 2 quantity remaining, I tried to modify the limit price of the order (without quantity and disclosed quantity in order to keep it unchanged) but received an error "Disclosed quantity should be greater than 10% of total order quantity for NSE."

    What is wrong here?
  • sujith
    Can you paste the exact params you sent here?

    BTW you can send only a new price, there is no need to send everything.
  • KNR
    Hi, suppose I have placed an order for 1000 quantity but at a moment only 300 filled. (700 unfilled at the moment)
    Now can I modify the order quantity to 1200? So that it has 900 unfilled at the moment. My system would wait for order to complete. Is it allowed to increase overall quantity of a partially filled order?

  • sujith
    Yes, you can modify the quantity of a partially filled order.
Sign In or Register to comment.