What is required for a U.S. application to be eligible for the PPH of another U.S. application?

To be eligible for the Patent Prosecution Highway (PPH) in relation to another U.S. application, the requirement that one application must claim priority and have at least one allowable claim is essential. The PPH is designed to expedite the examination process for related applications. For a U.S. application to enter PPH based on another application, it needs to show that it has been examined and that at least one of its claims has been found allowable by the examination office of the previous, or "parent", application.

The allowance of at least one claim is critical as it indicates that the claims have been evaluated and deemed to have patentable merit. This forms the basis of the expedited processing in the second application. Claiming priority backs up the relationship between the two applications, allowing for this expedited treatment based on prior favorable examination results.

Other factors, such as issues of ownership or similarity between the applications, while potentially relevant in broader contexts, are not required for eligibility in the specific context of PPH. Therefore, the requirement that one application claims priority and has an allowable claim distinctly lays out the necessary criteria for leveraging the benefits of the PPH process effectively.