The ACH ABA number, or routing transit number, is a nine-digit number that identifies each bank. This number, which may be obtained from the receiving bank, is necessary in order to complete a domestic bank-to-bank electronic transfer, which is how TransferWise sends out all USD payments.
For these payments, we can only accept electronic routing number (we cannot accept wire, or any other routing numbers even though they are visually very similar). Occasionally, banks will use the same ABA for ACH and wire payments, but when inquiring about an electronic funds transfer, be sure to specify that you intend to send the transfer via ACH.
To be sure which number your recipient has, you can check our FAQ on how to find the right number here.
If the incorrect number is used the payment will not be lost, but will eventually bounce back to us so we can either re-send or refund you. This can, however, take time and can cause avoidable delays to your payment, so it's best to get it right first time!