[MRM]

In general, emails and anything else generated by an employee during employer time or using employer resources belong to the employer. If an employee creates something at home and on his own time and simply transmits it via his empoyer's email, I don't think he has lost ownership, but the employee can't complain if the information is no longer confidential and it opens the door to the argument that it was the product of corporate resources and therefore belongs to the company.