Is there a refund if an inter partes reexamination request is denied?

Yes, there is a partial refund available if an inter partes reexamination request is denied. According to MPEP 2648:

“After the time for petition has expired (without a petition being filed), or a petition has been filed and the decision affirms the denial of the request, a partial refund of the filing fee for the request for reexamination is made to the third party requester. 35 U.S.C. 312(c) and 37 CFR 1.26(c).”

This means that if the request is denied and either no petition is filed within the allowed time frame or a petition is filed but unsuccessful, the requester will receive a partial refund of the filing fee.

To learn more:

Topics: MPEP 2600 - Optional Inter Partes Reexamination, MPEP 2648 - Petition From Denial Of Request, Patent Law, Patent Procedure
Tags: Filing Fee, inter partes reexamination, Refund, USPTO procedures