Assignment, license, or something in between
A transfer of patent ownership is usually done by assignment, and US law requires an assignment to be in writing. A license, even an exclusive one, generally leaves ownership where it was, although a sufficiently broad exclusive license can carry some ownership-like rights. The difference matters because the owner, not every licensee, is typically the party who can sue for infringement. Wording matters too: courts have treated a promise to assign in the future differently from language that transfers rights immediately. Co-ownership raises its own issue, because in the US each co-owner may generally use and license the patent without the others' consent unless an agreement says otherwise.
Chain of title and recording
Buyers should trace ownership forward from each inventor. Employment agreements, consulting contracts, and earlier assignments all need to line up, and a single missing inventor signature can leave part of the title somewhere else. Assignments should be recorded with the USPTO. Recording promptly protects a buyer against a later purchaser who had no notice of the earlier transfer, and delay can create real exposure. Check as well for security interests held by lenders, licenses already granted that survive the sale, the status of maintenance fees, and any pending challenges at the Patent Trial and Appeal Board. Foreign counterparts need their own transfers under each country's rules.
Setting up the transfer
We begin by identifying exactly which patents, applications, continuations, and foreign family members are in scope, since a vague schedule is a common source of later disputes. Then we review the inventor assignments and prior transfers, and decide whether the deal should include the right to sue for past infringement, which does not pass automatically with every assignment. Representations about ownership and known challenges deserve attention, along with what happens if a problem surfaces after closing. Bring the patent list, the inventor agreements you have, and any existing licenses. If the seller is overseas, we also check whether its home country imposes approval or registration requirements on outbound technology transfers.
