Tacking is a legal doctrine that allows a trademark owner to make slight alterations in a trademark, without abandoning ownership the original trademark. Changes in a trademark are often desirable to keep pace with advertising trends & societal changes. However, the doctrine applies only in exceptionally narrow circumstances.
Normally when the use of a trademark ends, the owner legally forfeits or abandons all rights in their mark (but see zombie trademarks). Tacking doctrine provides the bridge for reasonable updates over time. If a mark is properly tacked, the trademark owner can claim that the priority date of the earlier mark serves as the priority date of the latter mark, thereby avoiding the abandonment problem.
In order to tack properly, the two trademarks must create the same, continuing commercial impression. The general rule adopted has been that two marks may be tacked when the original and revised marks are “legal equivalents.” Key to this assessment is that consumers “consider both as the same mark.” This standard is hard to meet - even more difficult to meet than the material alteration standard used by the Trademark Office when deciding if an amendment to a trademark application is permissible or not.
Trademark tacking cases are obscure and thus exact parameters surrounding the right can be difficult to ascertain. For instance, in some jurisdictions the new and old versions of the trademark can co-exist (i.e. the new version commandeers the first-use date of the newer version even while the new version is still used in the marketplace). While it makes good common sense to allow for overlap at least for a commercially viable time to permit the change-over, prolonged overlap may be harder to defend, since the rationale behind allowing tacking is to allow companies to keep their marks updated, not to allow them to expand rights.
Examples of Trademark Tacking
Trademarks that have been denied tacking rights on the basis of being too dissimilar are:
DCI with dci
PRO-CUTS with PRO-KUT
CLOTHES THAT WORK with CLOTHES THAT WORK FOR THE WORK YOU DO
EGO with ALTER EGO
POLO with MARCO POLO
Trademarks that have been granted tacking rights are:
The morton salt girl images that have been updated over time