How do multiple assignees establish ownership in a patent application?

When multiple assignees seek to take action in a patent matter, each partial assignee must provide a submission under 37 CFR 3.73(c). According to the MPEP:

In each submission, the extent of each assignee’s interest must be set forth so that the Office can determine whether it has obtained action by the entirety of the right, title and interest holders (owners). 37 CFR 3.73(c)(2)(i).

Assignees have two options:

1. Specify the percentage of ownership interest for each assignee, accounting for 100% of ownership.
2. Identify all parties (including inventors) who together own the entire right, title, and interest, and state that all identified parties own the entire right, title, and interest.

The MPEP warns: “If the extent of the partial assignee’s ownership interest is not set forth in the submission under 37 CFR 3.73(c), the Office may refuse to accept the submission as an establishment of ownership interest.”