According to the Trademark Act, the exclusive licensee is entitled to take legal actions against trademark infringement as the trademark owner may take. Nonetheless, the Trademark Act also stipulates that the license cannot be cited against third parties unless the license is duly registered in Taiwan. Due to the unclear definition of the legal effect of unregistered license under the Trademark Act, it is a controversial issue whether the "unregistered" licensee is really entitled to file a civil litigation against trademark infringement or any other legal action. The Patent Act also stipulates a similar license clause governing the patent exclusive license.
The Supreme Court and some district courts or high courts used to take the view that unregistered trademark or patent licensees are not entitled to file civil litigations against infringement. Furthermore, the Fair Trademark Commission (the authority in charge of the Fair Trade Act governing unfair competitions) prohibits unregistered licensees from dispatching cease and desist letters against infringers.
Nonetheless, the Intellectual Property Court took different attitudes and held in some civil litigations against trademark infringement that the trademark exclusive licensee, no matter whether the license is registered in Taiwan or not, is entitled to file civil litigations against infringement.