The article is devoted to one of the modern media trends in social networks – reels, short vertical explanatory videos created to inform the audience that receives information from mobile devices. The article emphasizes the popularity of this format of information provision and its demand, which is confirmed by the data from various sociological surveys. A preliminary analysis of scientific sources has shown a lack of research on media’s reels. Authors characterize the few works of scholars, mostly foreign researchers, which partially reveal this object. It was found that most of the articles about the reels were written by practitioners, particularly in the marketing field. The publication aims to analyze reels’ genre specifics and characterize the legal rules for their creation. The task is to reveal reels as a popular media video format on Instagram, their genre features, and compliance with legal norms. Adequate research methods have been used: analysis, observation, description, comparative analysis, analytical and synthetic information processing, induction, deduction, generalization, and systematization. The paper emphasizes the active use of media, particularly BBC News Ukraine, in social networks of a new genre of short vertical videos, i.e., reels that are explanatory and well-received by the audience. Reels are characterized by specific editing, with previews, information hooks at the beginning, dynamic narration against the background of rapid image changes, and encouragement of the audience to comment and go to the media’s website as their mandatory components. Captions and audio play an important role in their composition. The studied videos comply with the current international legislation on freedom of speech, particularly Article 10 of the European Convention on Human Rights. They also comply with the national norms of the laws «On Information» and «On Media», as well as with the bylaws on limiting the dissemination of information about the war. The BBC complies with copyright law when using audiovisual content from other sources. It is summarized that reels are a powerful media tool for informing the audience on Instagram and explaining complex issues, which is specific in terms of editing and composition, and it meets current legal standards. The author emphasizes the prospect of further comparative studies of media reels.