First, please check if you already have a posted sell order for that stock. This error message appears when you attempt to post an order to sell more shares than was available in your account. 

You can check all posted orders in the following manner:

  1. Click on the TRADE menu tab followed by VIEW/MODIFY ORDER.
  2. Any posted order (whether partly filled or not) will be listed.

  3. You can filter the view option to show all Buying transactions, Selling transactions or its default to show any and all orders.

  4. You can also check the status of order details under the TRADE menu tab followed by TRADING HISTORY and clicking on Show Orders button under Order Details.

The order status posted means that the order had been received by the Exchange and is ready to be matched to sell orders at the same or better price.  Once the order finds a match, the status will update to EXECUTED or MATCHED. However, DAY orders are only valid on the same day they were posted and will automatically expire at the end of trading if unmatched.  Once expired, the order status will show CANCELLED.

To avoid this error, view your Uncommitted Shares first on your Portfolio before placing new orders. You may only post to sell the number of uncommitted shares as shown on your portfolio.  You must cancel your posted sell order first to reinstate your uncommitted share balance before attempting to post a new sell order.