Q&As

Can the assignment of a patent be retroactively effective?

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Produced in partnership with Joshua Marshall of Fieldfisher
Published on LexisPSL on 13/02/2018

The following IP Q&A Produced in partnership with Joshua Marshall of Fieldfisher provides comprehensive and up to date legal information covering:

  • Can the assignment of a patent be retroactively effective?

A patent or patent application is personal property that can be assigned (section 30(1) and (2) of the Patents Act 1977 (PA 1977)). In order to be effective, any assignment of patents or patent applications must be in writing and signed on behalf of the assignor (PA 1977, s 30(6)).

It is possible to retroactively assign a granted patent by, for example, entering an assignment agreement on 19 January 2018 under which the effective date from which the patent is deemed to have been assigned is 1 January 2018. As patents are personal property, a validly executed retroactive patent assignment should be effective as between the parties, but it appears that it is not effective against third parties.

In Effective dates: Roughton, Johnson and Cook: The Modern Law of Patents [10.31], it states:

‘Where the assignment of a patent is retrospective, so an agreement signed today is stated to assign the patent last week, this will only be effective between the parties and not against the world at large (and particularly not against the EPO)’, see para 3.5 of T 656/98

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