According to the Federal Circuit, the answer to this question appears to be "yes." The court reversed a district court's dismissal of a declaratory judgment action against a patent holding company (or non-practicing entity (NPE), sometimes pejoratively referred to as a patent troll). The DJ action was predicated on three letters, the first from the NPE to the DJ plaintiff, the second in reply, and the third from the NPE in reply to the second. The court held there was a sufficient "implied assertion of its rights" under the patent to support DJ jurisdiction.

Of particular note are some statements the court made regarding different rules when NPEs contact potential licensees for their patents. These include: