The article is devoted to the stylometric analysis of stories written by Jorge Luis Borges and Adolfo Bioy Casares under the common pseudonym Honorio Bustos Domecq. The work poses two questions: 1) Is Bustos Domecq’s style different from the writing style of Borges and Bioy Casares? 2) What is the share of influence of each of the co-authors on the formation of Bustos Domecq's style? To solve research problems, it is used Delta method, one of the most reliable stylometric tools to date; as well as the support vector machine, a common machine learning method that is used to solve classification problems. It turns out that Bustos Domecq's style differs from the style of the stories of Borges and Bioy Casares. However, in the texts of Bustos Domecq the authorial signal of Bioy Casares predominates, which is revealed on the basis of both stylometric and historical-literary analysis. The influence of Borges is more clearly manifested only in the first stories (1940s), when Bioy Caceres is a literary disciple of Borges, and in the second half of the 1960s, at a time of serious emotional upheavals for Borges, as well as his world recognition. Analysis of the topics of the stories, where Borges's authorial signal predominates, also confirms the results of stylometric experiments: the story “The Long Search for Tai An”, as well as the first texts of the collection The Chronicles of Bustos Domec “Tribute to Cesar Paladion”, “An Evening with Ramon Bonavena” and others really correspond to the poetics of Borges.