Do substitute and continuation-in-part applications require new assignments?

Yes, substitute and continuation-in-part (CIP) applications generally require new assignments. As stated in MPEP 306: In the case of a substitute or continuation-in-part application, a prior assignment of the original application is not applied (effective) to the substitute or continuation-in-part application because the assignment recorded against the original application gives the assignee rights to only the subject matter common to both applications.

However, there is an exception for applications filed on or after September 16, 2012: Substitute or continuation-in-part applications require the recordation of a new assignment if they are to be issued to an assignee, unless the substitute or continuation-in-part application is filed on or after September 16, 2012, and the assignee is the original applicant therein.