Method and system are disclosed for automatically filling in external account information on a new account application. The method and system capture account-identifying information for an external account from electronic transactions involving the external account. The captured external account information may be used to automatically pre-fill new account information fields that require information about the external account. Account-identifying information for internal accounts may also be used to automatically pre-fill the new account application. Such an arrangement greatly simplifies the process of filling out new account applications.