Good answers given, but I do seem to remember reading about a case where the person who was overpaid, put the money into a high interest account and left it there. When the bank realised what had happened, they sued this person who they say must have known that the money was not theirs and should have contacted the bank immediately to pay it back! I believe the bank was successful in it's case against this person, although my memory may be wrong. By removing the money your friend is showing that he realises it is not his, so as tempting as it may be to gain interest on the money, it may be better to contact the bank to let them know what has happened. Cheers Sue