Email is by far the most widely used mode of Communication in an Organization. But it also is a major source of Data Loss. One way the data is lost is when a user puts a forwarding rule in the mail box by which his mails get forwarded to his personal account. When this setting is put, even an admin cannot see which user is forwarding his emails.
Fortunately , if you are using Office 365 , then the admin can run some commands by which he will get a display of the users and also whether any user is forwarding his emails . The image below shows the list of email users. It also shows 2 users who have forwarded their emails to other accounts;
As the next step, the admin can also stop the email forwarding for accounts. This way you can ensure that there is no data loss due to email forwarding by users.