A U.S. answer.

In the US there is nothing about this that automatically makes the patent invalid. They listed all the inventors as required.

How did they handle not having a signed declaration from you? If they forged your signature that can be fraud on the office. Alternatively they could have said you had some agreement with them that justified them saying they tried to reach you but couldn’t (sometimes ok under the AIA law but not earlier) and therefore filed without your signature.

However, depending on the details, you might want to help them fix that up in retrospect and enjoy being exactly equal co-owners with ABC Ptd Ltd.

In the U.S. all rights flow from the inventors and the default is they can each make, sell, import, etc, and can each license with no consulting or accounting to each other, a horrible arrangement. This puts them in a horrible position and they might give you much to agree to a different arrangement.

In the rest of the world the applicant is often more important than the inventors do this is a U.S. only answer.

A U.S. answer.

In the US there is nothing about this that automatically makes the patent invalid. They listed all the inventors as required.

How did they handle not having a signed declaration from you? If they forged your signature that can be fraud on the office. Alternatively they could have said you had some agreement with them that justified them saying they tried to reach you but couldn’t (sometimes ok under the AIA law but not earlier) and therefore filed without your signature.

However, depending on the details, you might want to help them fix that up in retrospect and enjoy being exactly equal co-owners with ABC Ptd Ltd.

In the U.S. all rights flow from the inventors and the default is they can each make, sell, import, etc, and can each license with no consulting or accounting to each other, a horrible arrangement. This puts them in a bad position commercially and they might give you much money or royalty stream for you to agree to a different arrangement.

In the rest of the world the applicant is often more important than the inventors so this is a U.S. only answer.