Can an assignee file a patent application as the applicant?

Yes, for applications filed on or after September 16, 2012, an assignee can file a patent application as the applicant. According to MPEP § 409.05:

“An assignee or obligated assignee may file a patent application as the applicant. An assignee or obligated assignee doing so should record documentary evidence of ownership (e.g., assignment for an assignee, employment agreement for an obligated assignee) as provided for in 37 CFR part 3 no later than the date the issue fee is paid in the application.”

However, to be the sole applicant, the assignee must have been assigned the entire interest in the application.

For more information on patent applicant, visit: patent applicant.