Why was my ATON transfer rejected for "Invalid Delivery Account Number"?

A "notice of unconfirmed position transfer" message is sent to you if IBKR received a delivery of securities to your account for which you have not created an inbound transfer request in Client Portal to notify us about the expected delivery.

There is nothing for you to do if you expected to receive those securities (quantity and security identifier must be accurate). However, if you did not expect the delivery of those securities you must contact Interactive Brokers immediately to reverse the transaction through the Message Center. From the…

Instructions

• Your ACATS transfer can only be completed if your account number matches your broker's required format; otherwise, the broker will reject the request. To help prevent this, if the account number you provide does not match your broker's expected format, we may delay transmission and notify you to confirm the number with your broker and update it if needed…

When initiating an ATON transfer you are required to provide your account number at your broker but the account number listed on your statement may not be the complete account number required.  

Please review the below chart with the correct Account Format for your current broker. If the account number on your statement does not match the format listed in the chart please contact your broker for the remaining "check digits"…

In order for your ISA Transfer to be completed successfully, your ISA provider must validate the account number provided on the request. If the account number is invalid, your broker will reject the request.

IBKR recommends that clients review a copy of their brokerage statement to confirm their account number. We will provide below a list of some providers and their account format, however we…