The Maryland Notice of Filing of an Action Regarding a Patent or Trademark (AO 120) is a form used to notify the public that a party has initiated a legal action related to a patent or trademark. This document is typically filed with the Maryland Circuit Court and is used to establish a party’s legal rights in a case. The AO 120 form may be used for two different types of actions: 1) A Petition to Cancel a Trademark or Patent; or 2) A Petition to Correct an Error in a Trademark or Patent. The petitioner must provide the required information regarding the action, including the name of the petitioner, the name of the patent or trademark, the title of the action, and the case number. The petitioner must also provide a description of the action and the relief requested. Upon filing the AO 120 form, the court will issue a notice to the opposing party and publish a notice in a designated newspaper in the county where the action is pending. This notice informs the public of the action and provides a deadline by which any opposing party must respond. Failure to respond within the allotted time frame may result in a default judgment in favor of the petitioner.