This legislation requires the Financial Crimes Enforcement Network (FinCEN) to develop and issue an advisory concerning the procurement of firearms and firearm accessories by homegrown violent extremists and other perpetrators of domestic terrorism . The advisory's primary goal is to help financial institutions identify and report suspicious financial activity related to how these individuals acquire weapons for lone actor or lone wolf attacks within the United States. It also seeks to address how the firearms market is exploited to facilitate gun violence. To create this advisory, FinCEN must request information from financial institutions within one year of enactment, tailoring the request based on the institution's size. Before making this request, FinCEN is mandated to consult with the Director of the FBI, the Director of the ATF, and sellers of firearms and accessories. If sufficient information is collected within 540 days, FinCEN will issue the advisory; otherwise, it must submit a detailed report to Congress explaining why the information was insufficient. Additionally, FinCEN must promulgate rules within 90 days to define key terms such as "firearm accessory" and "homegrown violent extremist."